• Anovulatory Cycle: A menstrual cycle that takes place in the absence of ovulation.
  • Aspiration: A procedure for collecting eggs from ovaries using a needle which is passed into each follicle or fluid-filled sac. This if usually performed under ultrasound guidance through the vaginal wall. The fluid is then sucked out (“aspirated”) and under the microscope, the microscopic egg is separated from the follicular fluid.
  • Assisted Hatching (AH): A technique performed in the IVF lab whereby a small opening is created in the zona pellucida (eggshell) of the embryo in order to facilitate implantation of the embryo in the uterus.
  • Assisted Reproductive Technology (ART): Several procedures employed to bring about conception by manipulation of human gametes in the laboratory. Examples include IUI, IVF, GIFT as well as egg donation and surrogacy.
  • Azoospermia: Absence of any sperm in the ejaculate.


  • Biochemical Pregnancy: A transient and unsustained rise in the pregnancy hormone hCG (human chorionic gonadotropin).
  • Blastocyst: The stage of embryo development approximately 5 to 6 days after fertilization. At this stage, the embryo has a fluid-filled cavity (the balstocele) and is surrounded by and inner cell mas and an outer cell mass called the “trophectoderm.” It is the inner cell mass that goes on to develop the fetus.
  • Blastocyst Culture: The practice of extending the in vitro growth of the embryo until the fifth or sixth day after fertilization.


  • Chromosomes: Contained in a cell’s nucleus that holds the DNA. Every cell has 46 chromosomes with the exception of eggs and sperm, which have 23.
  • Clinical Pregnancy: A gestational sac in the uterus is visualized by ultrasound.
  • Controlled Ovarian Stimulation (Ovulation Induction): The safe use of fertility medications to restore normal ovulatory cycles in women who do not ovulate or who ovulate infrequently. Additionally, it is used to produce multiple follicles in women undergoing ART procedures, such as IUI and IVF, so as to increase the odds of conception.
  • Corpus Luteum: The yellow body formed in the follicle after an egg is released. The corpus luteum produces progesterone and estrogen after ovulation. Its role is to prepare the lining of the uterus (endometrium), for implantation of the fertilized egg (embryo). A deficiency in the amount of progesterone produced (or the length of time it is produced) by the corpus luteum can mean that the endometrium is unable to sustain a pregnancy. This is called luteal phase defect (LPD).
  • Cryopreservation: A process used to store cells or tissue in liquid nitrogen for short or long-term storage.
  • Culture Medium: The fluid solution used in the laboratory to grow cells in vitro.


  • Deoxyribonucleic acid (DNA): The molecules contained in the nucleus of that encodes the genetic information.
  • Dominant Follicle: The largest follicle that develops in a menstrual cycle which will release the egg at the time of ovulation.
  • Donor Egg Cycle: An IVF cycle in which a donor (known or anonymous) donates her eggs to be fertilized by either the husband’s sperm or donor sperm and the resulting embryos are transferred to the patient’s (recipient’s) uterus.
  • Donor Egg Bank: A place where egg donors’ vitrified (frozen) eggs are stored for future use by recipients.
  • Donor Insemination: Artificial insemination with donor sperm.


  • Ectopic Pregnancy: A pregnancy that implants outside of the uterus, usually in the fallopian tube.
  • Egg Retrieval: Retrieval of eggs from the ovary. Please see Aspiration.
  • Embryo: A fertilized egg that has gone through one or more cell divisions. This covers the stage from fertilization through the eighth week of pregnancy.
  • Embryo Transfer: Placing an egg fertilized outside the womb into a woman’s uterus using a small catheter usually passed through the cervix.
  • Endometrial Biopsy: A small tissue sample of the uterus is removed and analyzed to determine how receptive the lining of the uterus (endometrium) is to an embryo.
  • Endometriosis: A disease in which the cells of the uterine lining are found outside the uterus, usually on the ovaries and fallopian tubes. This can lead to tubal blockage and infertility.
  • Endometrium: Medical term for the lining of the uterus. It grows in response to estrogen stimulation, becomes receptive to implantation in response to progesterone and sheds in response to a fall in progesterone level if pregnancy does not occur.
  • Estradiol (E2): The principal estrogen produced by the ovary. Women undergoing fertility treatment, frequently have their estradiol levels measured.
  • Estrogen: The female sex hormone that is predominantly formed during the first half or follicular phase of the menstrual cycle. The production of this hormone drops significantly at the time of menopause.


  • Fallopian Tube: A narrow duct that carries the egg from the ovary to the uterus. Sperm normally meet the egg in the fallopian tube, the site at which fertilization usually occurs. Women typically have 2 fallopian tubes.
  • Fertilization: Penetration of an egg by a sperm.
  • Fetus: The stage of human development that follows the embryo which encompasses form the eighth weeks after fertilization until birth.
  • Fibroid (Myoma or Leiomyoma): A benign tumor of the uterus muscle and connective tissue.
  • Fimbria: The finger-like projections at the end of the fallopian tube nearest the ovary that pick up the egg as it is released from the follicle and deliver it into the fallopian tube.
  • Follicle: Fluid-filled sac in the ovary that contains the egg. At the time of ovulation, this follicle ruptures, releasing the egg.
  • Follicle-Stimulating Hormone (FSH): The hormone released from the pituitary gland that stimulates follicle growth in women and sperm formation in men.
  • Follicular Phase: The first half of a woman’s menstrual cycle during which a follicle grows and high levels of estrogen cause the lining of the uterus to proliferate.


  • Gamete: A reproductive cell: sperm in men, the egg in women.
  • Gestational Surrogacy: A pregnancy that is carried by a woman other than the mother. This usually occurs in situations when the mother has a medical condition that would make it is too dangerous for her to carry and deliver a pregnancy, or in cases where the mother has had a hysterectomy or a uterine anomaly that would prevent her from carrying a pregnancy to term and deliver. Gestational surrogates are also used for single men and gay male couples looking to have a child.
  • Gonadotropin Releasing Hormone (GnRH): The hormone released by the hypothalamus that controls the production and release of gonadotropins FSH and LH from the pituitary gland.
  • Gonadotropins: Follicle stimulating hormone (FSH) and luteinizing hormone (LH) which stimulate ovarian function in women and testicular function in men.


  • Hatching: The process by which the embryo breaks out of its shell, the zona pellucida, so that it can implant to the lining of the uterus.
  • Human Chorionic Gonadotropin (hCG): The hormone produced in early pregnancy. This hormone is similar to LH and is given in an IVF cycle 36 hours before aspiration to help the follicles release the eggs. It is also used in men to stimulate testosterone production.
  • Hyperolactinemia: Excessive prolactin hormone levels that may affect fertility.
  • Hysterosalpingogram (HSG): An x-ray that uses a special dye to evaluate the uterine cavity (for scar tissue, polyps, fibroids) and any tubal blockages or malformations in the fallopian tubes.
  • Hysteroscopy: A procedure used to examine the uterine cavity using a small telescope called a hysteroscope. Minor surgical repairs can be executed during the procedure.


  • Implantation: The attachment of the embryo to the uterine lining.
  • Intracytoplasmic Sperm Injection (ICSI): A procedure used to microscopically inject a single sperm into a mature egg to facilitate fertilization in the laboratory.
  • Intrauterine Insemination (IUI): The simplest form of ART whereby washed sperm are placed into the uterine cavity at an appropriate time via a small catheter passed through the cervix.
  • In Vitro Fertilization (IVF): An ART procedure that involves stimulating the ovaries to make follicles, aspirating the eggs from the ovaries and combining the eggs and sperm in the laboratory to achieve fertilization. The resulting embryos are cultured and grown in the laboratory and then transferred back into the woman’s body commonly through the cervix.


  • Laparoscopy: A surgical procedure used to examine the internal organs using a small telescope called a laparoscope. This involves making a very small incision near the navel through which the laparoscope is introduced.
  • Luteal Phase: The second half of a woman’s menstrual cycle which begins with ovulation and ends with the menses. It is characterized by the production of the progesterone by the corpus luteum
  • Luteinizing Hormone (LH): The pituitary hormone that stimulates ovarian function in women and testicular function in men. A large amount of this is produced in the middle of the menstrual cycle triggering ovulation.
  • Luteinizing Hormone Surge (LH surge): The release of large quantity of the luteinizing hormone (LH) from the pituitary gland that causes release of a mature egg from the follicle.


  • Menstruation: The shedding of the lining of the uterus which marks the end of one female cycle and the beginning of another.
  • Morphology: A term used in a semen analysis report to describe the shape and size of sperm. The lower the percentage of normal sperm, the less likely it is that fertilization of the egg will take place.
  • Motility: A term used in a semen analysis report to describe the ability of sperm to swim. Poor motility means that the sperm have a difficult time swimming toward their destination, the egg.


  • Oligomenorrhea: Infrequent menstrual periods.
  • Oligozoospermia: Low sperm count or concentration.
  • Oocyte: The female reproductive cell or egg.
  • Oocyte Retrieval: Oocytes (eggs) are aspirated from the ovarian follicles using a minor surgical procedure.
  • Ovarian Hyperstimulation Syndrome (OHSS): A potentially dangerous reaction to gonadotropins in which a woman’s ovaries become enlarged and produce an overabundance of eggs. Blood hormone levels rise, fluid may collect in the lungs or abdominal cavity, and cysts on the ovaries may rupture, causing internal bleeding. Blood clots sometimes develop.
  • Ovary: The female reproductive organ that contains the follicles which house the eggs.
  • Ovulation Induction (Controlled Ovarian Stimulation): The safe use of fertility medications to restore normal ovulatory cycles in women who do not ovulate or who ovulate infrequently. Additionally, it is used to produce multiple follicles in women undergoing ART procedures, such as IUI and IVF, so as to increase the odds of conception.


  • Pelvic Inflammatory Disease (PID): An infection of any of the pelvic organs that, if left untreated, may result in infertility.
  • Pituitary Gland: The gland at the base of the brain that secretes gonadotropins and other hormones.
  • Preimplantation Genetic Diagnosis (PGD): Genetic testing of embryos for specific diseases, prior to implantation, that would determine whether the embryos tested are free of disease.
  • Preimplantation Genetic Screening (PGS):  Genetic testing of embryos prior to implantation, that would determine whether the embryos tested are genetically normal.
  • Polycystic Ovarian Syndrome (PCOS or “Stein-Leventhal Syndrome”): A condition found in women who don’t ovulate, characterized by excessive production of androgens (male sex hormones) and the presence of cysts in the ovaries. Though PCOS can be without symptoms, some symptoms may include excessive weight gain, acne and/or excessive hair growth.
  • Progesterone (P4): The hormone produced by the corpus luteum during the second half of a woman’s menstrual cycle that prepares the endometrium for the implantation of an embryo.
  • Prolactin: The hormone produced by the pituitary gland that stimulates the production of milk in breastfeeding women. Excessive prolactin levels when not breastfeeding may result in infertility.


  • Secondary Infertility: The inability of a couple who has already successfully achieved at least one pregnancy to achieve another.
  • Semen: The mixture of sperm cells and seminal fluid released during ejaculation.
  • Seminal Fluid: The liquid that carries the sperm cells out of the male reproductive trace.
  • Septate Uterus: An abnormality in which the uterus is divided by a piece of tissue.
  • Sperm: The male reproductive cell.
  • Sperm Bank: A place where sperm are kept frozen in liquid nitrogen for later use in artificial insemination.
  • Sperm Count (Concentration) : A term used in a semen analysis report to describe the number of sperm in the ejaculate.
  • Sperm Washing: A laboratory technique using culture medium to separate the sperm cells from seminal fluid.
  • Superovulation: The use of fertility medications to stimulate the development of multiple follicles. This is also known as controlled ovarian hyperstimulation (COH).
  • Surrogate Mother (Traditional Surrogacy): A mother who carries an embryo conceived with her own eggs and the sperm of a male who wants a baby. This can be done via intrauterine insemination (IUI) or in vitro fertilization (IVF). The gestational surrogate is the biological mother of the child.


  • Testosterone: The primary male sex hormone.
  • Trophectoderm: The outer cell layer of the blastocyst.
  • Trophoblast: The cells of the embryo that are destined to become the placenta and produce hCG.


  • Ultrasound (Sonogram): Use of high-frequency sound waves that bounce off tissues and organs in the body in order to create an image on a monitor. Used to detect and count follicle growth (and disappearance) in many fertility treatments. Also used to detect and monitor pregnancy.
  • Unicornuate Uterus: An abnormality in which the uterus is one-sided and smaller than usual.
  • Uterus: The organ in the female reproductive tract that carries the fetus. The uterus is comprised of muscle and is lined by the endometrium.


  • Varicocele: A varicose vein in the testicle.
  • Vitrification:  A freezing or cryopreservation process which most IVF centers employ to freeze embryos.


  • Zona Pellucida: The hard protein shell surrounding the human egg.
  • Zygote: A fertilized egg that has not yet divided.

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