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Glossary



To locate the definition of a word pertaining to infertility and/or fertility medications, please select the first letter of the word from the below list:
A|B|C|D|E|F|G|H|I|K|L|M|O|P|R|S|T|U|V|W|X|Y|Z|

Ablation: Separation or detachment; extirpation; eradication. 2. removal or destruction of a part, expecially by cutting. Ablation of endometriomas.

Abortion: The premature ending of a pregnancy either spontaneously or by surgical intervention.

ACTH: A hormone produced by the pituitary gland to stimulate the adrenal glands. Excessive levels of this hormone may lead to fertility complications.

Adhesion: Scar tissue found in the fallopian tubes, abdominal cavity or within the uterus. Adhesions can interfere with egg transportation and uterine implantation of the embryo.

Adhesion: The sticking together of surfaces in the body by fibrous tissue; often as a result of infections or surgery. Adhesions over the ovary may interfere with ovulation. Adhesions can sometimes be removed using laser surgery.

Adrenal androgens: Male hormones produced by the adrenal gland that, when found in excess, may lead to fertility problems in both men and women. Excess androgens in the woman may lead to the formation of male secondary sex characteristics and the suppression of LH and FSH production by the pituitary gland. Elevated levels of androgens may be found in women with polycystic ovaries, or with a tumor in the ovary, adrenal gland or pituitary gland. Adrenal androgens can also be associated with excess prolactin levels.

Adverse Outcome: A pregnancy that does not result in a live birth. The adverse outcomes reported for ART procedures are miscarriages, ectopic (tubal) pregnancies, induced abortions, and stillbirths.

Agglutination: When sperm stick together - usually associated with antibodies which are part of the bodies fight against foreign cells -because the genetic makeup of the sperm nucleus is different from other cells in the body.

Agonist (Analog Agonist): A compound which competes for the receptor sites in the pituitary and after initial stimulation brings about a reduction in the secretion of FSH and LH - referred to as down regulation. See also analogues & antagonist.

Alpha fetoprotein test (AFT): A blood test performed to evaluate the development of the fetus and to look for fetal abnormalities.

Amenorrhea: Refers to a woman who has never had a period.

Amenorrhoea: Absence of menstruation.

American Society for Reproductive Medicine (ASRM): A professional society whose affiliate organization, the Society for Assisted Reproductive Technology (SART), reports annual fertility clinic data to the Centers for Disease Control and Prevention (CDC).

Amniocentesis: A test at 18 weeks where a small amount of fluid around the fetus is extracted to test for Down's Syndrome.

Analogs: A parallel or similar thing - often used to refer to drugs which have a similar effect to GNRH and which compete for the receptor sites in the gonadotropin secretory cells of the pituitary - e.g. Leuprolide, which suppress (down regulate) the pituitary.

Androgen: Male sex hormone responsible for male characteristics, e.g. voice, sperm production .

Andrologist: A physician-scientist who performs laboratory evaluations of male fertility. May hold a Ph.D. degree instead of an M.D. Usually affiliated with a fertility treatment center working on in vitro fertilization.

Anovulation: Absence of ovulation even though menstruation (periods) may continue.

Antagonist: A compound which blocks the production of gonadotropins (FSH & LH) in the pituitary –(ie. Ganirelix Acetate, Cetrotide). See also Analog Agonist.

Antibody (ies): Proteins produced by the body's fight against infection. Antibodies challenge foreign cells and substances.

Anticardiolipin Antibodies (ACA): An antibody directed against cardiolipin. These are one of the antiphospholipid group of antibodies. They are the most widely accepted and tested for immune factor. Approximately 80% of patients who have an antiphospholipid antibody problem will test positive for anticardiolipin antibodies, but the remaining 20% will test positive for one of the other six antiphospholipid antibodies.

Antisperm Antibodies (ASA): Antibodies are produced by the immune system to fight off foreign substances,like bacteria. Antisperm antibodies attach themselves to sperm and inhibit movement and their ability to fertilize. Either the man or the woman may produce sperm antibodies.

ART (Assisted Reproductive Technology): All treatments or procedures that involve surgically removing eggs from a woman's ovaries and combining the eggs with sperm to help a woman become pregnant. The types of ART are in vitro fertilization, gamete intrafallopian transfer, and zygote intrafallopian transfer.

ART Cycle: A process in which 1) an ART procedure is carried out, 2) a woman has undergone ovarian stimulation or monitoring with the intent of having an ART procedure, or 3) frozen embryos have been thawed with the intent of transferring them to a woman. A cycle begins when a woman begins taking fertility drugs or having her ovaries monitored for follicle production.

Artificial insemination: The depositing of sperm in the vagina near the cervix or directly into the uterus, with the use of a syringe instead of by coitus. This technique is used to overcome sexual performance problems, to circumvent sperm-mucus interaction problems, to maximize the potential for poor semen, and for using donor sperm. See also Artificial Insemination Donor; Artificial Insemination Homologous.

Artificial insemination donor: Artificial insemination with donor sperm. A fresh donor semen specimen or a thawed frozen specimen is injected next to the woman's cervix.

Artificial Insemination Homologous: Artificial insemination with the husband's sperm. The sperm may be washed and injected directly into the wife's uterus (IAIH). Often used with poor semen or to overcome sperm-mucus problems.

Artificial Spermatocoele: An artificial, surgically created pouch used to collect sperm from men with irreversible tubal blockage.

Asherman's Syndrome: A condition where the uterine walls adhere to one another. Usually caused by uterine inflammation.

Aspermia: The absence of sperm and semen.

Aspiration Cycle: An initiated ART cycle in which one or more follicles are punctured and aspirated irrespective of whether or not oocytes are retrieved.

Assisted Hatching: An in vitro procedure in which the zona pellucida of an embryo (usually at eight-cell stage or a blastocyst) is perforated by chemical, mechanical, or laser-assisted methods to assist separation of the blastocyst from the zona pellucida.

Asthenozoospermia: Poor motility (movement or swimming) of sperm in the seminal fluid.

Azoospermia: An absence of sperm in the seminal fluid.

Baby Aspirin: Low dose aspirin (80-100 mg) used in infertility treatment to increase blood flow to the uterus. Often used in conjunction with Heparin in patients with immune problems.

Bacterial Vaginosis: It occurs when the normal balance of bacteria in the vagina changes and an overgrowth of some bacteria normally found in the vagina occurs. It is associated with infertility, miscarriage, pre-term birth, and low-birth weight babies.

Balanced Translocation (BT): Is when a person has the correct number of chromosomes, but the pieces are joined up incorrectly. The problem can be inherited from one parent and then balanced out by the other. If both partners have similar problems, recurrent miscarriage may occur.

Basal Body Temperature (BBT): Your body temperature when taken at its lowest point, usually in the morning before getting out of bed. Charting BBT is used to predict ovulation. BBTs are not very reliable while taking fertility medications. Biphasic: A BBT pattern consistent with ovulation and the formation of the corpus luteum, which secretes progesterone. This hormone will elevate the basal body temperature about one-half degree during the latter half of the menstrual cycle. Monophasic: An anovulatory BBT pattern where the temperature remains relatively constant throughout the cycle. Triphasic: Similar to a biphasic BBT pattern, but adds a jump to a third level of temperatures around the time implantation should occur and may indicate pregnancy.

Beta HCG Test: A blood test used to detect very early pregnancies and to evaluate embryonic development. A beta test usually refers to a quantitative hCG in which the units of hCG are counted, but it sometimes refers to a qualitative (yes/no) test that reads to an hCG level under 50 (level is lab dependent).

Bicornuate Uterus: An abnormality of the uterus that occurs before birth. A partial or complete division of the body of the uterus. Bicornuate means, "two - horned".

Biopsy: Taking small pieces of tissue for microscopic study.

Blastocyst: An embryo that may have developed five days after fertilization.

Blastocyst Culture and Transfer: Fertilized eggs that have developed into a highly cellular embryo are transferred to the uterus when ready for implantation, usually at day 5.

Blastomere: A cell produced during cleavage of a fertilized egg.

Blighted Ovum: Fertilized ovum that fails to develop into an embryo leading to a miscarriage.

Caesarean Section: The surgical operation to remove the fetus and placenta by excising the abdominal wall and the lower segment of the uterus.

Cancelled Cycle: An ART cycle in which ovarian stimulation was carried out but which was stopped before eggs were retrieved, or in the case of frozen embryo cycles, before embryos were transferred.

Candida: A minor infection of genital tract causing minor irritation.

Capacitation: A process that occurs as sperm as pass through the female genital tract which gives them the ability to penetrate and fertilize the ovum. (This can be mimicked in culture medium).

Catheter: A hollow flexible tube used to aspirate or inject fluids (e.g. sperm or embryos into the uterine cavity).

Catheter: A thin tube for inserting materials into spaces.

Centers for Disease Control and Prevention (CDC): A government agency within the U.S. Department of Health and Human Services responsible for publishing annual fertility clinic success rates.

Cervical Smear: A sample of the cervical mucus examined microscopically to assess the presence of estrogen (ferning) and white blood cells, indicating possible infection.

Cervical Stenosis: A blockage of the cervical canal from a congenital defect or from complications of surgical procedures.

Cervix: The opening between the uterus and the vagina. The cervical mucus plugs the cervical canal and normally prevents foreign materials from entering the reproductive tract. The cervix remains closed during pregnancy and dilates during labor and delivery to allow the baby to be born.

Chemical Pregnancy: A pregnancy where hCG levels are detected, but the pregnancy is lost before a heartbeat is seen on an ultrasound. This is a very early miscarriage -- often before the woman misses a period.

Chlamydia: A common bacterial sexually transmitted disease that can lead to Pelvic Inflammatory Disease.

Chocolate Cyst: A cyst in the ovary that is filled with old blood; endometrioma. Occurring when endometriosis invades an ovary, it causes the ovary to swell. Frequently, patients with large endometriomas do not have any symptoms. If the cyst ruptures or the ovary containing the cyst twists, emergency surgery may be necessary. Usually treatment can be carried out through the laparoscope.

Chorionic Villus Sampling (CVS): An alternative to amniocentesis that can be done earlier in the pregnancy. It is a biopsy of the placenta that is used to check for genetic abnormalities in the fetus.

Chromosome - Chromosomal abnormalities: The chromosomes are thread-like structures within the nucleus which contain the hereditary material DNA. Mistakes in either chromosome numbers (46 in humans) or in structure can occur.

Chromotubation/Chromopertubation: This test is usually done in combination with a diagnostic laparoscopy. It involves injecting colored liquid through the fallopian tubes and watching the ends of the tubes for the dye. Spillage of dye indicates patent (open) tubes.

Cilia: Hairlike projections from cells which have the ability to move. Those in fallopian tubes assist with the movement of the ova (eggs) and sperm, in the lungs they help to sweep out mucus and dust particles.

Clinical abortion: The termination of a clinical pregnancy within the first 20 weeks of the gestational period.

Clomid: A brand name of clomiphene citrate.

Clomiphene Citrate (Clomid, Serophene): A fertility drug that stimulates ovulation through the release of gonadotropins from the pituitary gland.

Coitus: Sexual relations; making love; intercourse.

Colposcopy: Use of a scope to examine the cervix for abnormal cells.

Conception: The fertilization of an egg by sperm that leads to the creation of a new being.

Conceptus: The product of fusion of the male and female gametes.

Condom: Contraceptive sheath; prophylactic, rubber.

Continuing Infertile: Someone who has gone through primary infertility, successfully given birth, and is trying for another child.

Controlled Ovarian Hyperstimulation (COH): Using fertility medications to stimulate the growth of multiple follicles for ovulation. Also called Superovulation.

Corpus Luteum: The yellow-pigmented glandular structure that forms from the ovarian follicle following ovulation. The gland produces progesterone, which is responsible for preparing and supporting the uterine lining for implantation. Progesterone also causes the half-degree or more basal temperature elevation noted after ovulation. If the corpus luteum functions poorly, the uterine lining may not support a pregnancy. If the egg is fertilized, a corpus luteum of pregnancy forms to maintain the endometrial bed and support the implanted embryo. A deficiency in the amount of progesterone produced (or the length of time it is produced) by the corpus luteum can mean the endometrium is unable to sustain a pregnancy. This is called Luteal Phase Defect (LPD)

Corticosteroids: The aim is to suppress the immune system and reduce the antibody production.

Counseling: A process which enables people to explore their feelings, and to consider the consequences of taking certain decisions or accepting certain treatments.

Count: (Or Density) ) refers to the number of sperm present as millions per ml. e.g. 20 x 106.

Cryopreservation: Freezing quickly and then storing, as in sperm, embryos, and, more recently, unfertilized eggs.

Cryopreservation: Freezing tissues and storing them in liquid nitrogen at -196C / -320.8F. (sperm, eggs & embryos).

Cryptorchism: Undescended testis.

Culture Medium: This is the physiological salt solution which mimics the natural conditions under which fertilization and embryonic growth occur (in vitro).

Cycle Day: The day of a woman's menstrual cycle. The first day (day 1) is when full flow starts before mid-afternoon.

Cytoplasmic Transfer: An extension of in vitro fertilization which takes the genetic material from a mother's egg and combines it with the cytoplasma of a donor egg. Two methods of cytoplasm transfer were developed, one which transfers a small amount of cytoplasm by tiny needle from the donor to the recipient egg, the other transfers a larger amount of cytoplasm which is then fused to the recipient cytoplasm with electricity.

D & C: "Dilation & Curettage" a widening of the cervical canal to allow sampling of the lining of the womb - a diagnostic procedure. Often used to remove products of incomplete abortion or where the embryo has died at an early stage after IVF and embryo transfer.

Day 1: The first day of a woman's cycle with menses in full flow (not just spotting). Flow should begin before mid-afternoon or the next day would be considered Day 1.

Days Post-Ovulation (DPO): The number of days a woman is past ovulation. Counting begins the day after ovulation, so if ovulation is on Wednesday, Saturday would be 3 DPO.

Days Post-Transfer (DPT): The number of days a woman is past embryo transfer. Counting begins the day after transfer, so if is on Monday, Friday would be 4 DPO.

Differentiation: The point at which cells in the embryo become different from each other - i.e. become destined to be different parts of the body.

Dilation & Evacuation (D&E): A procedure in which the cervix is dilated and the baby and placenta are removed. D&E is used to describe two different procedures. One is similar to a D&C and uses more suction than scraping, and is performed on first trimester pregnancies. A D&E can also be used to describe a surgical removal of a fetus between 14-20 weeks gestation as an alternative to induced labor.

Dilation and Curettage (D&C): A procedure used to dilate (expand) the cervical canal and scrape out the lining and contents of the uterus. The procedure can be used to diagnose or treat the cause of abnormal bleeding and to terminate an unwanted pregnancy.

Direct Intra-peritoneal Insemination (DIPI, IPI): Injection of sperm into the peritoneal cavity. A form or artificial insemination that may be used with low sperm counts and motility.

Direct Oocyte-Sperm Transfer (DOST): Involves transvaginal retrieval of eggs from the stimulated ovary, just as in standard IVF. However, following retrieval, instead of inseminating the eggs with sperm and placing them into the incubator, the eggs are inseminated and transferred directly into the uterus nonsurgically two hours later. This allows the eggs to fertilize within the uterus, making it acceptable for women with damaged, nonfunctional or absent fallopian tubes, just as in IVF.

DNA: Deoxyribonucleic Acid. The double helix molecule responsible for hereditary and the molecule which controls cell function.

Donor Egg: Eggs donated by one woman to another.

Donor egg cycle (Egg Donation): An embryo formed from the egg of one woman (the donor) and then transferred to another woman who is unable to conceive with her own eggs (the recipient). The donor relinquishes all parental rights to any resulting offspring.

Donor Insemination: Artificial insemination with donor sperm. See Artificial Insemination, Intrauterine Insemination.

Doxycycline: A tetracycline derivative; an antibiotic that inhibits many of the microorganisms infecting the reproductive tract. Often used for treating ureaplasma infections. Many physicians find routine treatment with this antibiotic more cost-effective than performing multiple cultures on both the husband and wife looking for infection.

Dysmenorrhea: Painful menstruation.

Dysmenorrhoea: Painful menstruation.

Dyspareunia: Difficult or painful coitus.

Dyspareunia: Painful intercourse.

Ectopic Pregnancy: A pregnancy located outside of the uterus, usually in a fallopian tube. Such a pregnancy can rarely be sustained, and often leads to decreased or complete loss of function in the affected tube. Treatment is usually laparoscopic removal of the embryo or use of the chemotherapy drug Methotrexate that attacks fast growing cells and may dissolve the pregnancy without causing major damage to the tube.

Ectopic pregnancy: A pregnancy in which the fertilized egg implants in a location outside of the uterus usually in the fallopian tube, the ovary, or the abdominal cavity. Ectopic pregnancy is a dangerous condition that must receive prompt treatment.

Egg: A female reproductive cell, also called an oocyte or ovum.

Egg Donation: The act of donating eggs to someone else for use in attempting pregnancy through in vitro fertilization.

Egg Donor: A women who contracts to donate eggs to an infertile couple for in vitro fertilization.

Egg Retrieval: A procedure used to obtain eggs from ovarian follicles for use in several ARTs including in vitro fertilization, GIFT, and ZIFT. The procedure may be performed during laparoscopy or by using a long needle and ultrasound to locate the follicle in the ovary.

Egg transfer (also called oocyte transfer): A procedure to collect the eggs contained in the ovarian follicles. The procedure is performed by using a needle and ultrasound to locate the follicle in the ovary.

Ejaculate: The seminal fluid ejaculated from the penis: during male orgasm. Either as a result of intercourse or masturbation.

Elective Abortion: The voluntary termination of a pregnancy for non-medical reasons.

Electrocautery: Heat is used by surgeons to stop bleeding from small blood vessels.

Embryo: The early products of conception; the undifferentiated beginnings of a baby; the conceptus.

Embryo biopsy: Taking one or more cells (blastomeres) from an embryo (often at the 8 cells stage but can now with laser techniques be at the blastocyst stage) for genetic or sex analysis. DNA hybridization (amplification technique) allows analysis in a very short time. Enables good embryos without screenable genetic abnormalities to be chosen.

Embryo Toxic Factor (ETF): An immune response against a woman may have against her own fetus in a pregnancy that may result in the loss of the pregnancy. Treatment is high doses of progesterone until the 16th week of pregnancy.

Embryo Toxicity Assay (ETA): A combination of two procedures. The first involves maternal cell (lymphocyte) culture which is aimed at stimulating the lymphocytes using components of the human embryo (trophoblast) cell line, and the second is an embryo culture. These procedures are used to measure if the patient's lymphocytes secrete anything that be toxic to the embryo (test utilizes two-cell stage mouse embryos). Women who have been sensitized in the course of their earlier pregnancies or in any other mode, could amass an immune response against their own fetus in the following pregnancy, and end up losing it (in the implantation process or later in the first trimester).

Embryo Transfer (ET): Placing an egg fertilized outside the womb into a woman's uterus or fallopian tube.

Embryologist: Scientist with training and skills in handling sperm, eggs, embryos in the laboratory.

Endocrine: Endocrine glands produce hormones which are passed into the bloodstream and affect parts of the body which are often distant from the gland itself.

Endocrine Gland: An organ that produces hormones.

Endocrine System: System of glands including the hypothalamus, pituitary, thyroid, adrenals and testicles or ovaries.

Endocrinologist: A doctor / scientist who specializes in disorders of the endocrine glands and the study of hormones.

Endogenous: Naturally occurring hormones - as opposed to exogenous (added hormones or drugs by injection or inhalation.

Endometrial Ablation: The womb lining is destroyed e.g. by laser. This is an alternative treatment to hysterectomy.

Endometrial biopsy: A procedure during which a sample of the uterine lining is collected for microscopic analysis.

Endometrial Biopsy (EB, Ebx, EMB): A test to check for Luteal Phase Defect or Hyperplasia. A procedure during which a sample of the uterine lining is collected for microscopic analysis. The biopsy results will confirm ovulation and the proper preparation of the endometrium by estrogen and progesterone stimulation.

Endometriosis: Growth of endometrial tissue outside the uterus. The tissue may attach itself to the reproductive organs or to other organs in the abdominal cavity. Each month the endometrial tissue inbreeds with the onset of menses. The resultant irritation causes adhesions in the abdominal cavity and in the fallopian tubes. Endometriosis may also interfere with ovulation and with the implantation of the embryo.

Endometriosis: A medical condition involving the presence of tissue similar to the uterine lining in locations outside of the uterus, such as the ovaries, fallopian tubes, and abdominal cavity.

Endometritis: An inflammation of the endometrium.

Endometrium: The lining of the womb which develops in response to estrogen and progesterone stimulation at the beginning of each cycle so that it is ready to receive a fertilised egg. If there is no embryo then the endometrium breaks down and menstruation begins.

Endorphins: Natural narcotics manufactured in the brain to reduce sensitivity to pain and stress. May contribute to stress-related fertility problems.

Endoscopy: The visualization of the interior of the body using instruments such as the laparoscope, culdoscope or hysteroscope.

Epididymis: A coiled, tubular organ attached to and lying on the testicle. Within this organ the developing sperm complete their maturation and develop their powerful swimming capabilities. The matured sperm leave the epididymis through the vas deferens.

Estimated Due Date (EDD): An approximate date for when a baby is due to be born. It is generally calculated based on LMP, when LMP is two weeks before ovulation. To figure the due date, take your LMP and add 9 months plus one week. To figure EDD based on ovulation, add 9 months and subtract one week. When using ARTs, one would consider the day of insemination to be ovulation, and the day of egg retrieval to be ovulation.

Estradiol (E2): The principal estrogen produced by the ovary. Responsible for formation of the female secondary sex characteristics such as large breasts; supports the growth of the follicle and the development of the uterine lining. At midcycle the peak estrogen level triggers the release of the LH spike from the pituitary gland. The LH spike is necessary for the release of the ovum from the follicle. Fat cells in both obese men and women can also manufacture estrogen from androgens and interfere with fertility. The blood test to monitor estradiol is E2 -- Rapid Assay. Women on injectable fertility drugs have routine E2 monitoring.

Estrogens: The female sex hormones. First recognized around 1915, estrogen is responsible for the development of the secondary feminine sex characteristics, which include breasts, rounded hips, and pubic hair. Together with progesterone, another female hormone made by the ovaries, estrogen regulates the changes that occur with each monthly period and prepares the uterus for pregnancy. See Estradiol.

Ethics committee: A body of independent people representing a wide range of disciplines, with a high lay representation which can advise or rule on ethical matters - can be local (i.e. considering matters for a local hospital or clinic or national.

Exogenous: Something applied from out side (ex) - usually drugs or hormones.

Fallopian Tubes: Ducts through which eggs travel to the uterus once released from the follicle. Sperm normally meet the egg in the fallopian tube, the site at which fertilization usually occurs. The fallopian tube is divided anatomically into a few regions: closest to the uterus and within the uterine wall is the "interstitium" (where interstitial pregnancies develop), next is the "isthmus" (immediately outside the uterine wall) then the "ampulla" (midsection of the tube) and then the "infundibular or fimbrial portion" (adjacent to the ovary at the end of the tube).

Falloscopy: Falloposcopy is the visual examination of the inside of the fallopian tube. A tiny flexible catheter is inserted through the cervical canal and uterine cavity into the fallopian tube. A small flexible fiber optic endoscope is threaded through the catheter into the fallopian tube. A camera at the end of the falloscope transfers images of the inside of the tube to a monitor so the surgeon can thoroughly visualize and examine the inside of the tube. If problems are found, surgical repairs can be made at the same time.

Fasting Blood Glucose (FBG): Blood glucose levels taken after not eating or drinking anything other than water overnight. A normal level is under 110, over 110 shows impaired glucose tolerance or insulin resistance, and over 126 is diabetic. Its ratio in comparison to fasting insulin can also indicate insulin resistance.

Fasting Blood Insulin: Insulin levels taken after not eating or drinking anything other than water overnight. Insulin is a hormone released to break down sugar. Its ratio in comparison to fasting blood glucose can indicate insulin resistance.

Fecundity: The ability to conceive a pregnancy and carry it to term.

Fertile Mucus: Mucus that allows sperm to thrive and makes its way into the cervical canal into the uterus and tubes. It resembles raw egg whites and is both stretchy and watery. Non-fertile mucus blocks sperm from entering the cervix.

Fertility: The ability to conceive a pregnancy.

Fertility Microscope: A small microscope women can purchase to view saliva or cervical mucus as a low-tech way of predicting ovulation.

Fertility Treatment: Any method or procedure used to enhance fertility or increase the likelihood of pregnancy, such as ovulation induction treatment, varicocoele repair, and microsurgery to repair damaged fallopian tubes. The goal of fertility treatment is to help couples have a child.

Fertilization: The combining of the genetic material carried by sperm and egg to create an embryo. Normally occurs inside the fallopian tube (in vivo) but may also occur in a petri dish (in vitro). See also In Vitro Fertilization.

Fetus: A term used to refer to a baby during the period of gestation between eight weeks and term.

Fetus: The unborn offspring from the eighth week after conception to the moment of birth.

Follicle: Structure in the ovaries that contains a developing egg.

Follicle Aspiration, Sperm Injection and Assisted Rupture (FASIAR): A procedure involving the use of ultrasound for guidance to remove eggs from their follicles. Sperm and eggs are mixed inside the syringe and then injected back into the patient. If the woman develops too many eggs, the physician can remove some and reduce the risk of multiple pregnancy.

Follicle Stimulating Hormone (FSH): A pituitary hormone that stimulates spermatogenesis and follicular development. In the man FSH stimulates the Sertoli cells in the testicles and supports sperm production. In the woman FSH stimulates the growth of the ovarian follicle and production of estrogen. Elevated FSH levels are indicative of gonadal failure in both men and woman, and is an indicator of menopause.

Follicle Tracking: A series of ultrasound scans which monitor the growth of the follicle/s in the ovary. Used to confirm ovulation and monitor treatment with gonadotropin therapy.

Follicular Fluid: The fluid inside the follicle that cushions and nourishes the ovum. When released during ovulation, the fluid stimulates the fimbria to grasp the ovary and coax the egg into the fallopian tube.

Follicular Phase: The pre-ovulatory portion of a woman's cycle during which a follicle grows and high levels of estrogen cause the lining of the uterus to proliferate. Normally takes between 12 and 14 days.

Follistim: Recombinant FSH injectable fertility medication used for superovulation.

Fresh eggs, sperm, or embryos: Eggs, sperm, or embryos that have not been frozen. However, fresh embryos may have been conceived using fresh or frozen sperm.

Frozen cycle (cryopreservation): A cycle in which embryos are preserved through freezing (cryopreservation) for transfer at a later date.

Frozen Embryo Transfer (FET): A procedure where frozen embryos are thawed and then placed into the uterus.

Fundus: The upper portion of the uterus.

Gametes: Male and female reproductive cells - see sperm and ova.

Genes: Parts of the chromosomes that control the inheritance of specific hereditary characteristics.

Genetic: Inherited hereditary characteristics.

Genome: All the genetic material within the cells of an individual.

Gestation: The period of time from conception to birth.

Gestational carrier (also called a gestational surrogate): A woman who carries an embryo that was formed from the egg of another woman. The gestational carrier usually has a contractual obligation to return the infant to its intended parents.

Gestational sac: A fluid-filled structure that develops within the uterus early in pregnancy. In a normal pregnancy, a gestational sac contains a developing fetus.

GIFT (gamete intrafallopian transfer): An ART procedure that involves removing eggs from the woman's ovary, combining them with sperm, and using a laparoscope to place the unfertilized eggs and sperm into the woman's fallopian tube through small incisions in her abdomen.

GNRH: Gonadotropin Releasing Hormone is secreted by the hypothalamus, is responsible for the pituitary initiating the production of gonadotropin hormones (FSH & LH).

Habitual abortion: A condition in which a woman has had three or more miscarriages.

Hatching: The process by which the blastocyst emerges from the zona pellucida before implantation.

Hostility Factor: This is used to describe a poor interaction between cervical mucus and sperm. This can be due to poor timing of test, ovulation problems, poor quality sperm, infection in either partner or antibody production.

HRT - Hormone Replacement Therapy: Also called Hormone Therapy: Substitute for the female hormones estrogen and progesterone, given when levels fall due to menopause.

Human Chorionic Gonadotropin (HCG): The hormone produced by placental cells (afterbirth) in pregnancy. Detection of this hormone in blood or urine is the basis of pregnancy testing. This hormone mimics the Luteinizing Hormone (LH) normally produced by a woman at ovulation time. Preparations for this are used to stimulate ovulation and sometimes given following procedures like IVF or GIFT to help the embryo implant.

Hydrocele: A swelling of the scrotum caused by an accumulation of fluid.

Hydrosalpinx: A fluid filled swelling of the outer ends of one or both fallopian tubes.

Hyperplasia: An abnormal enlargement of tissues or organs in the body.

Hypothalamus: A part of the brain that serves as a link between the higher centers of the brain and the pituitary gland. It controls the activity of the pituitary gland.

Hysterectomy: Removal of the uterus.

Hysterosalpinogram (HSG): An x-ray of the pelvic organs in which a radio-opaque fluid is injected through the cervix into the uterus and fallopian tubes. This test checks for malformations of the uterus and blockage of the fallopian tubes. Sometimes called “tubogram”.

Hysteroscopy: Diagnostic procedure in which a lighted scope (hysteroscope) is inserted through the cervix into the uterus to enable to the physician to view the inside of the ut Hysteroscopic myomectomy: A procedure in which the doctor removes a uterine fibroid while using a hysteroscope.

Hysterotomy: An opening of the uterus to perform a surgical procedure.

ICSI (intracytoplasmic sperm injection): A procedure in which a single sperm is injected directly into an egg; this procedure is most commonly used to overcome male infertility problems. Induced or therapeutic abortion A surgical or other medical procedure used to end a pregnancy.

Immunological Response: The formation of antibodies. In infertility, this usually refers to antibodies produced by the man or woman that affects sperm quality or the sperm’s ability to function.

Impaired Fecundity: Difficulty conceiving or carrying a pregnancy to term, including situations in which pregnancy has been deemed medically risky for the woman and/or her offspring.

Implantation: The embedding of a fertilized ovum in the endometrium of the uterus - Blastocyst , The embryo proper (the inner cell mass) is the group of cells at the bottom of the blue 'cyst' The cells around the outside of the blastocyst (the trophoblast cells) will form the placenta linking up with the rapidly developing blood vessels in the endometrium.

Impotence: The inability to achieve or maintain an erection for successful intercourse. Can be caused by emotional or physical problems, or both.

Incomplete abortion: A term referring to when some tissue remains inside the uterus after an abortion. To remove the tissue and prevent complications, a D&C is typically performed.

Infertility: Difficulty achieving conception. In many studies, infertilty is defined as the failure of a couple to cenceive, despite unprotected intercourse, after a certain amount of time (usually 6 - 12 months). Can be described as primary or secondary infertility.

Inhibin: A hormone produced by the ovaries and testes. Inhibin B is produced by the dominant follicle and results in the suppression of FSH secretion from the pituitary.

Interstitial Cells: The cells between the seminiferous tubules of the testes (Leydig cells) that produce the male hormone.

Intrauterine Device (IUCD) -Contraceptive: Used as a contraceptive.

IUI (intrauterine insemination): A medical procedure that involves placing sperm into a woman's uterus to facilitate fertilization. IUI is not considered an ART procedure because it does not involve the manipulation of eggs.

IVF (in vitro fertilization): An ART procedure that involves removing eggs from a woman's ovaries and fertilizing them outside her body. The resulting embryos are then transferred into the woman's uterus through the cervix.

Kleinfelter's syndrome: A congenital abnormality syndrome in men - one X chromosome too many - men are sterile.

Lamina flow hood: A semi enclosed space in the laboratory where a flow of filtered sterile air flows across the working surface keeping cells and embryos in a clean environment.

Laparoscopic myomectomy: Removal of a uterine fibroid by using a laparoscope, a small telescope that can be inserted into a hole in the abdominal wall for viewing the internal organs. A laparoscope can be used to diagnose and treat a number of fertility problems including endometriosis, abdominal adhesions, and polycystic ovaries.

Laparoscopy: A surgical procedure in which a fiber optic instrument (a laparoscope) is inserted through a small incision in the abdomen to view the inside of the pelvis.

Laser: Light Amplification by Stimulated Emission of Radiation - used in surgery to cut or destroy tissue, e.g. Endometriosis, adhesions etc.

Live Birth: The delivery of one or more babies with any signs of life.

Luteinizing Hormone: A pituitary gonadotropin hormone which stimulates both Hormone (LH) maturation and rupture of the follicle in women. High LH often produces low or absent follicle production.

Male Factor: Any cause of infertility due to deficiencies in sperm quantity or that make it difficult for a sperm to fertilize an egg under normal conditions.

Menarche: The beginning of the menstrual cycle in girls at puberty.

Menopause: The cessation of menstruation that occurs around the age of 45 - 50, the 'change of life'. This is said to be premature when it occurs in a woman under the age of 35.

Menstruation: Vaginal bleeding which is part of a cycle of hormonal events. This normally begins at puberty & occurs throughout a woman’s reproductive life unless she is pregnant or breast-feeding.

Micromanipulation: An IVF laboratory process in which the egg or embryo is held with special instruments and treated by procedures such as ICSI, assisted hatching, or embryo biopsy.

Microsurgical Epididymal Sperm Aspiration (MESA): Sperm are aspirated from the testes and used in the IVF procedure.

Miscarriage (also called spontaneous abortion): A pregnancy ending in the spontaneous loss of the embryo or fetus before 20 weeks of gestation.

Missed abortion: An abortion in which the fetus dies in the uterus without bleeding or cramping. A D&C is typically performed to remove the fetus' remains and prevent further complications.

Mittelschmerz: A German term used to describe the “middle pain” which occurs in some women when they ovulate.

Morphology: Refers to the shape or form of the cells – in particular of the sperm.

Motility: The power of movement. Usually used to describe sperm which move under their own power (as %).

Mucus (cervical): Fluid produced by specialized cells in the cervix. This changes under the influence of hormones. At ovulation time the mucus appears clear and stretchy (like uncooked egg white) it is then able to be penetrated by the sperm.

Multifetal pregnancy reduction: A procedure used to decrease the number of fetuses a woman carries and improve the chances that the remaining fetuses will develop into healthy infants. Multifetal reductions that occur naturally are referred to as spontaneous multifetal reductions.

Multiple birth: A pregnancy that results in the birth of more than one infant.

Multiple gestation: A pregnancy with multiple fetuses.

Obstetrician: A doctor who specializes in the supervision of pregnancy and childbirth.

Obstructive & Non Obstructive: Terms used to define the absence of sperm in the semen-i.e. as a result of a blockage (obstructive) or as a result of lack of spermatogenesis (non obstructive).

Oligospermia: A condition in which there are fewer sperms in the ejaculate than are considered normal.

Oocyte: The female reproductive cell, also called an egg.

Oocyte Cryopreservation: Freezing of egg cells to keep them viable.

Ovarian Cyst: A fluid-filled sac inside the ovary. An ovarian cyst may be found in conjunction with ovulation disorders, tumors of the ovary, and endometriosis.

Ovarian Drilling Using Electrocautery: Small holes burned in the ovary can induce ovulation in some women with polycystic ovary syndrome.

Ovarian Hyperstimulation Syndrome (OHSS): A potentially serious complication of gonadotropin therapy in which there is excessive stimulation of the ovaries. An overabundance of eggs can be produced, blood hormone levels rise, fluid may collect in and around the lungs, heart and/or abdominal cavity. Frequent ultrasound and hormone level monitoring can aid in prevention. Symptoms include sudden weight gain, abdominal pain, and shortness of breath and urine concentration.

Ovarian Monitoring: The use of ultrasound and/or blood or urine tests to monitor follicle development and hormone production.

Ovarian Stimulation (Induction): The use of drugs to stimulate the ovaries to develop follicles and eggs.

Ovaries: The female gonads which produce oocytes and hormones. Situated in the pelvis near t the fimbrial ends of the fallopian tubes.

Ovulation: The production and release of an egg from the follicle of the ovary. Usually occurs about 14 days prior to menstruation.

Ovulation Dysfunction: A cause of infertility due to problems with egg production by the ovaries.

Pap Smear: Removal of cells from the surface of the cervix to study microscopically.

Patent: Open, unobstructed. Term used with respect to the fallopian tubes.

Pelvic inflammatory disease (PID): An infection of the pelvic organs. PID may lead to tubal blockage and pelvic adhesions.

Pituitary: The master gland of the endocrine system. Located at the base of the brain and produces several hormones. Receptor sites on secretory cells in the pituitary receive the GNRH signals from the hypothalamus and respond by secreting FSH and LH. Analogue agonists compete for these sites and downregulate their activity lowering the secretions. Anatgonists block the GNRH and hence prevent the secretions.

Placenta: The embryonic tissue that implants in uterine wall and provides a mechanism for exchanging the baby's carbon dioxide and waste products for the mother's nutrients and oxygen. The baby is connected to the placenta by the umbilical cord.

Polycystic ovarian syndrome: Development of multiple cysts in the ovaries due to arrested follicular growth due to lack of ovulation. Can cause problems with ovulation and implantation.

Polyp: A nodule or small non-cancerous growth found on mucus membranes. Can occur in the cervix or uterus.

Post-coital test (PCT): A diagnostic test, which allows observation of semen/mucus interaction. A sample of mucus is taken from the woman's cervix at ovulation time, sexual intercourse having taken place some hours earlier.

Pregnancy (clinical): Pregnancy documented by the presence of a gestational sac on ultrasound. For ART data collection purposes, pregnancy is defined as a clinical pregnancy rather than a chemical pregnancy (i.e., a positive pregnancy test).

Preimplantation genetic diagnosis (PGD): A procedure performed in conjunction with IVF in which one or two cells are removed from an embryo prior to the initiation of pregnancy and screened for genetic abnormalities.

Premature Menopause: The occurrence of the menopause before the age of 40 affects between 1 and 2% of women. It may be caused by congenital reasons (Turner's Syndrome), nutritional disturbances, auto-immune disease, hypogonadism, or following radiation or chemotherapy. It is confirmed by blood hormone tests (elevated serum FSH) and by inactivity on ultrasound scanning.

Primary Infertility: Infertility in persons who have never had children.

Products of Conception (POC): Tissues resulting from a pregnancy, such as the embryo/fetus and placenta. The term is often found on pathology reports where miscarriages are analyzed.

Progesterone: A hormone produced by the corpus luteum after ovulation has occurred. The placenta also produces it in pregnancy.

Progestin: Synthetic progesterone (Provera).

Prolactin: The hormone that stimulates the production of milk in breastfeeding women. Excessive prolactin levels when not breastfeeding may result in hormone imbalances and ovulatory dysfunction.

Pronuclei: The stage immediately after fertilization before the gametes have fused. Usually only visible for a short time at 18-22 hours after fertilization. After fusion the pronuclei are no longer visible & shortly after that stage cell division (cleavage) commences. Normal fertilization contains 2 Pronuclei.

Prostate: A gland, found only in men, that surrounds the first part of the urethra, as it leaves the base of the bladder, produces an alkaline fluid essential to the survival of sperm.

Retrograde Ejaculation: A male fertility problem that allows the sperm to travel into the bladder instead of out the opening of the penis due to a failure in the sphincter muscle at the base of the bladder.

Retroverted Uterus: Uterus that is tilted back toward the rectum.

Rhogam (Anti-D): An immunization given to Rh-negative women after a miscarriage, stillbirth, or live birth to prevent production of antibodies in any Rh-positive babies they may have in future pregnancies.

Salpingectomy: Surgical removal of the fallopian tubes.

Salpingitis: An inflammation of one or both fallopian tubes.

Scrotum: The bag of skin and thin muscle (sac) surrounding the man's testicles, epididymis, and part of the vas deferens.

Secondary amenorrhea: A term describing a woman who has menstruated at one time, but who has not had a period for six months or more.

Secondary Infertility: Infertility in persons who have already had children.

Secondary Sex Characteristics: The physical qualities that distinguish man and woman, such as beard, large breasts, and deep voice. Formed under the stimulation of the sex hormones (testosterone or estrogen), these characteristics also identify those people who have gone through puberty (sexual maturity).

Semen (Seminal Fluid): The ejaculate fluid containing sperm and secretion from the testicles, prostate, and seminal vesicles.

Semen analysis / Sperm count: The study of fresh ejaculate under the microscope to count the number of sperms per cubic milliliter, also to assess their shape (morphology) and to assess their swimming ability (motility).

Semen donation: A process in which semen may be obtained from a donor bank.

Seminiferous Tubules: The long tubes in the testes in which sperm are formed.

Sertoli cells: Cells which line the seminiferous tubules of the testes and nurture the generation of spermatozoa (spermatogenesis). In some men there is a condition known as 'Sertoli cell only 'syndrome - where there are no spermatogenic cells to generate spermatozoa - only the supporting Sertoli cells.

Sexually Transmitted Disease: Any infection that can be sexually transmitted, such as chlamydia, gonorrhea, ureaplasma, and syphilis. Many of these diseases will interfere with fertility and some will cause severe illness. See also PID.

Single embryo transfer: Placement of a single embryo into the uterus.

Society for Assisted Reproductive Technology (SART): An affiliate of the American Society for Reproductive Medicine composed of clinics and programs that provide ART. SART reports annual fertility clinic data to CDC.

Speculum: An instrument used to aid examination of the vagina and the cervix.

Sperm: The male reproductive cell.

Sperm Penetration: The ability of the sperm to penetrate the egg so it can deposit the genetic material during fertilization.

Spermatazoa: The medical name for the male reproductive cells. Abbreviated as Sperm.

Spinnbarkeit: The stretchability of cervical mucus; the stringy quality that occurs at midcycle under the influence of estrogen.

Spontaneous abortion: Loss of pregnancy within the first 20 weeks of gestation.

Spontaneous Miscarriage/Spontaneous Abortion: An unplanned end to a pregnancy during the first 20 weeks. See Abortion.

Stem Cell: One of the human body's master cells, with the ability to grow into any one of the body's more than 200 cell types. All stem cells are unspecialized/undifferentiated cells that can give rise to other cells of the same type indefinitely or from which specialized cells such as blood cells develop. Embryonic stem cells are derived from embryos created in vitro. The inner cell mass from the blastocyst is extracted, and used to generate an embryonic stem cell line.

Sterility: Permanent infertility, an irreversible condition that prevents conception.

Sterilization: A surgical procedure designed to cause infertility, such as a tubal ligation or vasectomy.

Stillbirth: The death of a fetus between the twentieth week of gestation and birth. e the subject of cancer and other research such as transplants etc.

Stimulated Cycle: An ART cycle in which a woman receives oral or injected fertility drugs to stimulate her ovaries to produce more follicles.

Superovulation: Using fertility medications to stimulate the growth of multiple follicles for ovulation. Also known as Controlled Ovarian Hyperstimulation (COH).

Surgical sperm retrieval: The extraction of sperm from the male reproductive tract can be accomplished using a variety of procedures including needle aspiration or biopsy. Also called Testicular biopsy/Epididymal aspiration.

Surgical Sterility: Inability to conceive or carry a pregnancy to term as a result of surgery. This category includes both the "contraceptively sterile," people who have sterilizing operations such as tubal ligation or vasectomy, and the "noncontraceptively sterile," people who are sterile as a result of surgery for other medical conditions (such as endometriosis, fibroid tumors or cancer).

Surrogacy: A woman carrying and giving birth to a baby whom she gives to another women. Gestational Carrier - the IVF procedure is used so the surrogate caries the child that is not genetically related to her. Full Surrogacy - the surrogate is inseminated with the man's semen from the commissioning couple. Illegal in many countries or not practiced. Complicated by different regulations about who is the mother.

Synarel: A synthetic hormone used to treat endometriosis or for regulation before or during a controlled ovarian hyperstimulation cycle.

Terato(zoo)spermia: A condition in which less than 50% of the sperm are morphologically normal.

Teratogen: Any substance capable of causing malformations in a developing embryo.orphologically normal.

Test term: Test definition

Testicle/Testes: The testes are male gonads (situated in the scrotum) they produce and store sperm. The vas deferens carries the spermatozoa to the urethra, picking up secretions from the seminal vesicles and prostate gland on the way.

Testicular Failure: Primary: A congenital, developmental, or genetic error resulting in a testicular malformation that prevents sperm production. Secondary: Acquired testicular damage, for example, from drugs, prolonged exposure to toxic substances, or a varicocoele.

Testicular Sperm Aspiration (TESA): A needle biopsy of the testicle used to obtain small amounts of sperm.

Testicular Sperm Extraction (TESE): An open biopsy where a small piece of testicular tissue is removed through a skin incision. The tissue is placed in culture media and separated into tiny pieces. Sperm are released from within the seminiferous tubules where they are produced and are then extracted from the surrounding testicular tissue.

Testosterone: The main male sex hormone produced by the testes.

TET: See Tubal Embryo Transfer.

Thaw Cycle: A cycle in which frozen embryos are thawed for transfer.

Therapeutic abortion: A procedure used to purposely terminate a pregnancy before the fetus can survive on its own.

Therapeutic Donor Insemination (TDI): An alternative description for DI and which stresses that the treatment is for 'therapeutic' purposes.

Threatened abortion: This term applies to when spotting or bleeding occurs early in the pregnancy, with the threat to progress to a spontaneous abortion.

Thyroid Gland: The endocrine gland in the front of the neck that produces thyroid hormones to regulate the body's metabolism.

Thyroid Releasing Hormone (TRH): A peptide hormone synthesized in the hypothalamus. In the anterior pituitary, TRH stimulates synthesis and release of Thyrotropin (TSH).

Thyroid Stimulating Hormone (TSH): Also called thyrotropin. A hormone produced by the pituitary gland (at the base of the brain) that promotes the growth of the thyroid gland (in the neck) and stimulates it.

Thyroxine (T4): A hormone produced by the thyroid gland. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism) in the body.

Torsion: The twisting of the testis inside the scrotum. Besides causing extreme pain and swelling, the rotation twists off the blood supply and causes severe damage to the testicle. Torsion of the ovary may also occur in a woman suffering from hyperstimulation, a complication of ovulation induction treatment.

Transvaginal: Through the vagina or across its wall as in a surgical procedure.

Transvaginal Ultrasound: An ultrasound examination performed by means of inserting a probe into the vagina. This type of ultrasound is common for viewing follicle growth This can produce better images in early pregnancy that could be obtained with conventional abdominal sonograms.

Triiodothyronine (T3): Hormone secreted from the thyroid gland.

Tubal Factor: Structural or functional damage to one or both fallopian tubes that reduces fertility.

Tubal Ligation: Surgical sterilization of a woman by obstructing or tying the fallopian tubes.

Tubal Patency: Open and unobstructed fallopian tubes.

Tubal Pregnancy: See Ectopic Pregnancy.

Tubal Reanastomosis: Reversal of a tubal ligation.

Tuboplasty: Plastic or reconstructive surgery on the fallopian tubes in order to correct abnormalities which may lead to blockage or otherwise cause infertility.

Tumor: An abnormal growth of tissue that can be benign or malignant (cancerous).

Turner's Syndrome: A congenital condition in which a woman has one less X chromosome, rendering her sterile.

Ultrasound: A technique used in ART for visualizing the follicles in the ovaries and the gestational sac or fetus in the uterus. High frequency sound waves are bounced into the pelvis and as they bounce back are used to build up a picture.

Undescended Testicles (Cryptorchidism): The failure of the testicles to descend from the abdominal cavity into the scrotum by one year of age. If not repaired by age six, may result in permanent fertility loss.

Unexplained Infertility: Infertility for which no cause has been determined despite a comprehensive evaluation.

Unicornate Uterus: An abnormality in which the uterus is "one sided" and smaller than usual.

Unstimulated Cycle: An ART cycle in which the woman does not receive drugs to stimulate her ovaries to produce more follicles. Instead, follicles develop naturally.

Urethra: The tube that allows urine to pass between the bladder and the outside of the body. In the man this tube also carries semen from the area of the prostate to the outside.

Urinary Tract Infection (UTI): Infection of the kidney, ureter, bladder, or urethra. Common symptoms include a frequent urge to urinate and a painful, burning when urinating, but symptoms are not always present.

Urologist: A doctor who specializes in disorders of the urinary system. He/she also often has an interest in male genital disorders.

Uterine factor: A disorder in the uterus (e.g., fibroid tumors) that reduces fertility.

Uterine myomectomy via laparotomy: Removal of a uterine fibroid through an abdominal incision.

Uterus: A small, hollow, muscular organ that carries the fertilized ovum through the nine months of pregnancy, enlarging to accommodate it as it grows. Also known as the womb.

Vagina: 'Front passage' or 'birth canal' - the tube that leads from a woman's uterine cervix to the outside (vulva).

Vaginal Oocyte Retrieval: The eggs are aspirated from the ovary through the vaginal wall by ultrasound guided needle aspiration.

Vaginal ultrasound: Ultrasound imaging of the female reproductive system through an ultrasound device inserted into the vagina.

Vaginismus: A spasm of the muscles surrounding the opening of the vagina, making penetration during sexual intercourse either impossible or very painful. Can be caused by physical or psychological conditions.

Vaginitis: An inflammation of the vagina. Yeast, bacterial vaginosis, or trichomonas infections of the vagina.

Varicocele: A varicose vein of the testes (normally the left). The resulting swollen vessels surrounding the testicles create a pool of stagnant blood, which elevates the scrotal temperature. A cause of male infertility.

Vas Deferens: The pair of thick-walled tubes through which the sperm move from the epididymis to the ejaculatory duct in the prostate. These tubes are severed during a vasectomy performed for birth control.

Vasectomy: The surgical separation of both vas deferens to prevent the sperm from being present in the seminal fluid at ejaculation. A procedure used for birth control/sterilization.

Vasectomy Reversal: Surgical repair of previous vasectomy in order to restore fertility.

Viable: Capable of sustaining life. Often used to describe an early pregnancy in which a heartbeat has been seen.

Virus: A microscopic infectious organism that reproduces inside living cells.

Viscosity: The thickness of semen.

Vulva: Female's external genitalia.

Womb: See Uterus.

X Chromosome: The congenital, developmental, or genetic information in the cell that transmits the information necessary to make a female. All eggs contain one X chromosome, and half of all sperm carry an X chromosome. When two X chromosomes combine, the baby will be a girl.

Y Chromosome: The genetic material that transmits the information necessary to make a male. The Y chromosome can be found in one-half of the man's sperm cells. When an X and a Y chromosome combine, the baby will be a boy.

ZIFT (zygote intrafallopian transfer): An ART procedure in which eggs are collected from a woman's ovary and fertilized outside her body. A laparoscope is then used to place the resulting zygote (fertilized egg) into the woman's fallopian tube through a small incision in her abdomen.

Zona Pellucida: The protective outer membrane surrounding the egg.

Zygote: A fertilized egg which has not yet divided.