Glossary
A B C–D E F G H I–K L M N O P Q R S T U V–Z
Artificial insemination: The most common form of insemination into the vagina. Can involve the use of donor sperm in cases where the woman's partner is infertile or the woman chooses to conceive without the participation of a partner.
Assisted hatching: The zona pellucida, or outer covering, of the embryo is partially opened, to aid implantation.
Assisted reproductive technology (ART): A phrase to describe any treatments that involve handling human eggs or embryos.
Blastocyst: The stage at which a cavity develops within the young embryo.
Blastomere: Cell within the developing embryo. Each blastomere is capable of developing into an identical embryo until the embryo reaches about the thirty-cell stage, after which time the cells begin to differentiate into specific tissues.
Blood hormone test-LH: When this test is performed several times daily around the presumed time of ovulation, the detection of a rapidly rising blood LH concentration can accurately determine the time of probably ovulation.
Capacitation: The process by which sperm are prepared for fertilization as they pass through the woman's reproductive tract; sperm may also be capacitated in the laboratory.
Cervical canal: The connection between the outer cervical opening and the uterine cavity.
Cervical mucus: Mucus produced by glands in the cervical canal; this mucus plays an important role in initiating the capacitation of sperm.
Cervix: Lowermost part of the uterus, which protrudes like a bottleneck into the upper vagina; the cervix opens into the uterus through the narrow cervical canal.
Chemical pregnancy: Biochemical evidence of a possible developing pregnancy based on a positive blood or urine pregnancy test; at this point, pregnancy is presumptive until confirmed by ultrasound.
Chlamydia: Bacteria that are responsible for a sexually transmitted infection that may damage the fallopian tubes and/or the male reproductive ducts, thereby causing infertility.
Chromosomes: Structures in the nuclei of cells, such as the egg and sperm, on which the hereditary or genetic material is arrayed.
Cleavage: The process of cell division.
Clinical pregnancy: A pregnancy that has been confirmed by ultrasound examination or through pathologic examination of a surgical specimen obtained either from a miscarriage or from an ectopic pregnancy. A clinical pregnancy should be distinguished from a chemical pregnancy, which through a positive blood pregnancy test merely suggests that the possibility that a pregnancy has occurred.
Clomiphene citrate: A synthetic hormone that is used alone or in combination with other fertility drugs to induce the ovulation of more than one egg.
Clomiphene challenge test: A blood test to measure FSH taken on days 3 and 10 of the menstrual cycle. Clomiphene citrate is given on days five through nine to induce ovulation.
Conception: Creation of a zygote by the fertilization of an egg by a sperm.
Conceptus: A term used to describe the developing implanted embryo and/or early fetus.
Controlled ovarian hyperstimulation (COH): In response to the administration of fertility drugs, the maturation of several follicles simultaneously, which results in the production of an exaggerated hormonal response.
Cryopreservation: The process of freezing in liquid nitrogen and storing eggs, sperm and embryos for future use.
Egg: The female gamete, which develops in the ovary; also known as an ovum or oocyte. An egg is the largest cell in the human body.
Egg retrieval: The retrieval of eggs from the ovarian follicles prior to ovulation; the eggs are sucked out of the follicles through a needle under ultrasound guidance.
Electroejaculation: A procedure that involves electrically stimulating tissue near a man's prostrate to cause ejaculation.
Embryo: The term for a fertilized egg from the time of initial cell division through the first six to eight weeks of gestation. Thereafter the embryo begins to differentiate and take on human organic form; at this point it is traditionally referred to as a fetus.
Embryo transfer: The process whereby embryos that have been grown in vitro are transferred into the uterus.
Endometriosis: A condition in which the endometrium grows outside the uterus, causing scarring, pain, and heavy bleeding, and often damaging the fallopian tubes and ovaries in the process. Endometriosis is a common organic cause of infertility.
Endometrium: The lining of the uterus which grows during the menstrual cycle under the influence of estrogen and progesterone. The endometrium grows in anticipation of nurturing an implanting embryo in the event of a pregnancy; it sloughs off in the form of menstruation if implantation does not occur.
Estradiol (E2): A female hormone produced by ovarian follicles. The concentration of estrogen in the woman's blood is often measured to determine the degree of her response to controlled ovarian hyperstimulation with fertility drugs; in general, the higher the estradiol response, the more follicles are likely to be developing and, accordingly, the more eggs are likely to be retrieved.
Estrogen: A primary female sex hormone, produced by the ovaries, placenta, and adrenal glands.
FSH/Follicle Stimulating Hormone: A gonadotropin (hormone) that is released by the pituitary gland (or sometimes given by injection) to stimulate the ovaries or testicles.
Fallopian Tubes: Narrow 4-inch long structures that lead from either side of the uterus to the ovaries.
Fertilization: The union of the sperm and egg to form a zygote.
Fertility Drugs: Natural or synthetic hormones that are administered to a woman in order to stimulate her ovaries to produce as many mature eggs as possible or to a man in an attempt to enhance sperm function.
Fetus: Once the embryo differentiates and begins to take on identifiable human-like organic form, it is termed a fetus; the fetal stage of development usually begins around the eighth week of pregnancy.
Fibroid Tumor: A tumor in the uterus, which may prevent the embryo from properly implanting into the endometrium or might cause pain, bleeding, miscarriage, and symptomatic enlargement of the uterus.
Fibrous Bands: Scar tissue that may distort the interior of the uterus and prevent the embryo from implanting properly.
Fimbraie: Finger-like protrusions from the ends of the fallopian tubes that retrieve the egg or eggs at the time of ovulation.
Follicles: Blister-like structures within the ovary that contain eggs and that produce female sex hormones.
Follicular phase of the menstrual cycle: Usually the first half of the menstrual cycle, when the endometrium proliferates under the influence of estrogen and the follicles develop.
Gamete: The female egg and male sperm.
Gestation: The period from conception to delivery.
Gestational Surrogate: When an infertile woman uses someone else's uterus to carry a child to term for her. The surrogate does not contribute biologically and undergoes IVF treatment to prepare her body to accept the embryo(s).
GnRH/Gonadotropin-releasing hormone: A "messenger hormone" released by the hypothalamus to influence the production of gonadotropins (FSH and LH) by the pituitary gland.
GnRH agonists: GnRH-like hormones that block the body's release of both FSH and LH. Through blocking LH production, GnRH agonists are capable of improving a woman's reponse to fertility drugs and may be used in combination with fertility drugs to promote an enhanced response in women who demonstrate resistance to controlled ovarian hyperstimulation.
Gonads: The ovaries and testicles.
Gonadotropins: The gonad-stimulating hormones LH and FSH, which are relea sed by the pituitary gland to stimulate the testicles in the man and ovaries in the woman.
Growth medium: A physiological solution that promotes cleavage and development of the embryo.
hCG/Human chorionic gonadotropin: A hormone, produced by the implanting embryo, and subsequently also by the placenta, whose presence in the woman's blood indicates a possible pregnancy; hCG may also be administered to women undergoing stimulation with hMG alone or in combination with other fertility drugs in order to trigger ovulation. Injections of hCG may also be administered to encourage the production of progesterone by the corpus lutuem in the hope of promoting implantation following embryo transfer and thereby reducing the incidence of spontaneous miscarriage in a pregnancy resulting from IVF. The hormone is derived from the urine of pregnant women.
hMG/Human menopausal gonadotropin: A natural hormone that is administered either alone or in combination with other fertility drugs to induce ovulation of more than one egg. The hormone hMG is derived from the urine of menopausal women.
Hormonal insufficiency: A condition resulting in infertility and/or miscarriage; in the IVF setting, hormonal insufficiency may be produced by abnormal response to fertility drugs and may lead to the failure of the embryo to implant because the amount of hormones produced and the timing of their production and release were not perfectly synchronized.
Hormone (sex hormone): Chemicals produced by the testicles, ovaries and adrenal glands, which play a major role in reproduction and sexual identity.
HSG/Hysterosalpingogram: A procedure used to assess the interior of the fallopian tubes and uterus; it involves injecting a radio-opaque dye into the uterus via the vagina and cervix and tracking the dye's pathway by a series of x-rays.
Hypothalamus: A small area in the midportion of the brain that, together with the pituitary gland, regulates the formation and release of many hormones in the body, including estrogen and progesterone by the ovaries and testosterone by the testes.
Hysteroscope: A lighted, telescope-like instrument that is passed through the cervix into the uterus, enabling the physician to examine the cervical canal and the inside of the uterus for defects or disease.
Hysteroscopy: Examination of the cervical canal and inside the uterus for defects by means of the hysteroscope. Surgery designed to correct such defects can be performed through the hysteroscope during this procedure, thereby often making more invasive abdominal surgery unnecessary.
Infertility: The inability to conceive after one full year of normal, regular heterosexual intercourse without the use of contraception.
Implantation: The process that occurs when the embryo burrows into the endometrium and eventually connects to the mother's circulatory system.
Insemination: In the laboratory, the addition of a drop or two of the medium containing sperm to a Petri dish containing the egg in order to achieve fertilization; also refers to the placement of sperm into the woman's reproductive tract.
Insemination medium: A liquid that bathes and nourishes the eggs and embryos in the Petri dish just as the mother's body fluids sustains them in nature.
Intrauterine insemination/IUI: The injection of sperm into the uterus by means of a catheter directed through the cervix; enables sperm of poor quality to reach and fertilize the egg more easily or to bypass hostile cervical mucus.
Intracytoplasmic sperm injection (ICSI): A procedure in which a single sperm is injected directly into an egg to help spur fertilization, used primarily with male infertility.
Intramuscularly: Within a muscle: an intramuscular injection.
In-vitro fertilization/IVF: Literally "fertilization in glass", IVF comprises several basic steps: the woman is given fertility drugs that stimulate her ovaries to produce a number of mature eggs; at the proper time, the eggs are retrieved by suction through a needle that has been inserted into her ovaries; the eggs are fertilized in a glass Petri dish, or in a test tube, in the laboratory with her partner's sperm (or donor sperm); and subsequently the embryos are transferred into the uterus.
In-vivo fertilization: Fertilization that occurs inside the body.
Lithotomy: Position that a woman is asked to assume in order to undergo a gynecological examination or other procedures, such as embryo transfer, vaginal ultrasound examinations, etc.
Luteal phase of the menstrual cycle: The second half of the menstrual cycle, which begins after ovulation under the influence of estrogen and progesterone produced by the corpus luteum.
Luteinizing hormone (LH): A gonadotropin released by the pituitary gland to stimulate the ovaries and testicles. This hormone normally causes a women to ovulate and her eggs to mature.
Menopause: The period of a woman's life that begins with the total cessation of menstruation, usually between the ages of 40 and 55.
Menstrual Cycle: The time that elapses between menstrual periods. The average cycle is 28 days, with ovulation usually occurring at the midpoint (around the 14th day).
Menstruation: The monthly flow of blood when pregnancy does not occur; the flow comprises about two-thirds of the endometrium and blood, often including the unfertilized egg or unimplanted embryo.
Microepididymal sperm aspiration (MESA): A procedure for collecting sperm from men whose reproductive ducts are blocked, usually as a result of a vasectomy or absence of vas deferens (the tubes that carry sperm to the urethra).
Miscarriage: Spontaneous expulsion of the products of conception from the uterus in the first half of pregnancy.
Mitosis: The identical replication of cells by cleavage; mitosis is the process responsible for the growth and development of all tissues.
Motility (sperm motility): The ability of sperm to move and progress forward through the reproductive tract and fertilize the egg; sperm motility can be assessed microscopically.
Multiple pregnancy: The presence of more than one gestation within the women's reproductive tract at the same time.
Myceles: Microfibers within the cervical mucas that sperm must swim through to reach the uterus; the woman's hormonal environment determines whether the arrangement of the myceles will facilitate or inhibit passage of the sperm. Around the time of ovulation the myceles are arranged in a parallel fashion so that sperm can swim between them in order to reach the uterus; it is believed that capacitation is initiated during that process.
Nucleus: Structure in the cell that bears the chromosomes.
Ovarian hyperstimulation syndrome (OHSS): A potentially life-threatening condition characterized by enlargement of the ovaries, fluid-retention and weight gain that may occur when the ovaries are over-stimulated during assisted reproduction.
Ovaries: Two white, almond-like structures, the female counterpart of the testicles, that are attached to each side of the pelvis adjacent to the ends of the fallopian tubes; the ovaries both release eggs and discharge sex hormones into the bloodstream.
Ovulation: The process that occurs when an ovary releases one or more eggs.
Ovum: See egg.
Patency: Openness, freedom from blockage (particularly referring to the fallopian tubes).
Penis: The male external sex organ.
Percutaneous epididymal sperm aspiration (PESA): A procedure in which a needle is inserted into the gland that carries sperm from the testicle to the vas deferens in order to extract sperm for an IVF procedure.
Pituitary Gland: A small, grape-like structure hanging from the base of the brain that, together with the hypothalamus, produces and regulates the release of many hormones in the body.
Placenta: The factory that nourishes the fetus throughout pregnancy and is connected to the baby's belly button via the umbilical cord.
Polycystic ovarian disease/PCO: Condition in which the ovaries develop multiple small cysts; it is often associated with abnormal or absent ovulation and, accordingly, with infertility.
Polyps (uterine): Outgrowths that protrude into the uterus and may cause pain and bleeding or prevent an embryo from implanting.
Polyspermia: The entry of more than one sperm into an egg during fertilization; this causes the zygote to die or the embryo to divide haphazardly and then die.
Postcoital test (PCT): Assessment of the cervical mucas after intercourse to evaluate the quality of the mucus and mucus-sperm interaction; also known as the Huhner test.
Preimplantation genetic diagnosis (PGD): A test in which one or two cells are removed from an embryo and screened for genetic abnormalities.
Progesterone: A primary sex hormone produced by the corpus luteum that induces secretory changes in the glands of the endometrium. Progesterone may also be given by injection or in the form of vaginal suppositories to enhance implantation and reduce the risk of miscarriage.
Prolactin: A hormone produced by the brain that influences the activity of FSH on the ovaries.
Prostrate gland: Gland in the male reproductive tract that secretes a milky substance that nurtures and promotes survival of sperm.
Purified FSH: A fertility hormone that is derived by processing and purifying hMG to eliminate the LH component.
Quantitative Beta hCG blood pregnancy test: Test that detects and measures the amount of hCG (produced by implanting embryo) in the woman's blood. Measured 10-14 days after embryo transfer it can diagnose a possible pregnancy before the woman has missed a menstrual period.
Retrograde ejaculation: A condition, sometimes causes by the removal of a diseased prostrate gland, in which the man ejaculates backward into the bladder rather than outward through the penis. It may cause infertility but can be treated by inseminating the woman with sperm separated from urine the man would pass immediately following orgasm.
Scrotum: Pouch in which the male's testicles are suspended outside the body.
Semen: The combination of sperm, seminal fluid, and other male reproductive secretions.
Seminal fluid: Milky fluid produced by the seminal vesicles that is ejaculated during orgasm.
Sperm: The male gamete; spermatozoa.
Sperm antibody test: Test that determines whether either partner's blood or the woman's cervical mucus contains antibodies to sperm.
Sperm count: A basic fertility-assessment test of sperm function, primarily involving counting the number of sperm, assessing their motility and progression, and evaluating their overall structure and form.
Spontaneous menstrual abortion: An early miscarriage occurring at the time of menstruation without the woman's menstrual period being delayed.
Stimulation: Induction of the development of a number of follicles in response to the administration of fertility drugs. (See also controlled ovarian hyperstimulation and superovulation).
Superovulation: The ovulation of more than one egg induced through the administration of fertility drugs. (See also controlled ovarian hyperstimulation and stimulation).
Surrogate: When an infertile woman uses someone else's uterus to carry a child to term for her. Surrogacy can be divided into two types: traditional and gestational.
Subcutaneous: Located or placed just beneath the skin: subcutaneous tissue.
Syphilis: A life-endangering venereal disease that in its late stages attacks most systems in the body, including the cardiovascular and central nervous system.
Testes: See testicles.
Testicles: The male counterparts of the female ovaries; located in the scrotum, the testicles produce sperm and male hormones such as testosterone.
Testicular sperm extraction (TESE): Surgery to remove testicular tissue and collect living sperm for use in an IVF or ICSI procedure.
Testosterone: The predominant male sex hormone, which influences the production and maturation of sperm.
Traditional surrogacy: When an infertile woman uses someone else's uterus to carry a child to term for her. In this type of surrogacy, the surrogate mother contributes biologically to the offspring by providing her own eggs. The procedure used is typically intrauterine insemination.
Transvaginal egg retrieval: An ultrasound guided egg retrieval procedure in which the needle is passed through the back or side of the woman's vagina into her ovaries.
Treatment cycle: The menstrual cycle during which a particular fertility treatment such as IVF or IUI is performed.
Tubal pregnancy: See ectopic pregnancy.
Tubal Ligation (Female Sterilization): Tubal ligation, commonly knows as "getting your tubes tied," is a surgical sterilization technique for women. This procedure closes the fallopian tubes, and stops the egg from traveling to the uterus from the ovary. It also prevents sperm from reaching the fallopian tube to fertilize an egg. In a tubal ligation, fallopian tubes are cut, burned, or blocked with rings, bands or clips. The surgery is effective immediately. Tubal ligations are over 98% effective as birth control. They do not protect against reproductive tract infections, including HIV/AIDS.
Ultrasound: A painless diagnostic procedure that transforms high frequency sound waves as they travel through body tissue and fluid into images on a TV-like screen; it enables the physician to clearly identify structures within the body and to guide instruments during certain procedures. Ultrasound is also used to diagnose a clinical pregnancy.
Umbilicus: The umbilicus, also called the navel, is essentially a scar representing the former attachment of the umbilical cord in the fetus. Colloquial terms for navel are belly button and tummy button.
Unexplained infertility: Infertility whose cause cannot be readily determined by conventional diagnostic procedures; this occurs in about 10–15 percent of all infertile couples.
Urine ovulation test: A simple test that can pinpoint the time of presumed ovulation; frequent charting of the test results detects the surge of LH that triggers ovulation.
Uterus: A muscular organ that enlarges during pregnancy from its normal pear-shaped size to accommodate a full-term pregnancy.
Vagina: The narrow passage that leads from the vulva to the cervix. The vagina's elastic tissue, muscle, and skin have enormous ability to stretch to accommodate the penis during the sex act and the passage of a baby during childbirth.
Variococele: A collection of dilated veins around the testicles that hinders sperm function.
Vas deferens: Tube that connects the epididymis with the urethra in the male reproductive tract.
Vasectomy: Surgery to block the male's sperm ducts for the purpose of birth control.
Vulva: The external portion of the female reproductive tract.
Zona-free hamster-egg penetration test: A technique that helps determine whether sperm are likely to fertilize healthy eggs.
Zona Factor: Zona pellucida is the thick membrane around the ovum; can be penetrated by one sperm in the fertilization process; usually remains around the fertilized egg until it is implanted in the wall of the uterus.
Zona pellucida: The shell-like covering of the human egg.
Zygote: The term for a fertilized egg until it begins to cleave, at which time it is known as an embryo.