Glossary of Fertility Terms and Acronyms

Originally published 09/10/2019. Updated for accuracy and relevancy on 10/26/2023.

It sometimes feels like the world of fertility has its own language. We’ve broken down some common acronyms you may hear in online forums or even your doctor’s office, as well as definitions of some medical terms.

Reviewed by Dr. Kenosha Gleaton, OBGYN

Common Fertility Acronyms

• AF: Aunt Flo (period)
• ART: Assisted reproductive technology
• BBT: Basal body temperature
• BCP: Birth control pills
• BD: Baby dance (sex)
• BFP: Big fat positive
• BFN: Big fat negative
• CM: Cervical mucus
• D&C: Dilation and curettage
• IVF: In-vitro fertilization 
• ICSI: Intracytoplasmic sperm injection 
• IUI: Intrauterine Insemination 
• PCOS: Polycystic ovary syndrome
• POAS: Pee on a stick (take an ovulation/pregnancy test)
• REI: Reproductive endocrinologist and infertility specialist
• RB: Rainbow baby
• TTC: Trying to conceive
• TWW or 2WW: Two week wait

Definitions of Common Fertility Terms

• AMH (Anti-Müllerian Hormone): AMH is produced by the granulosa cells surrounding each oocyte in the developing ovarian follicle. The production and serum levels of antimüllerian hormone at any given time are reflective of a woman’s ovarian reserve.
• Amenorrhea: Lack of periods.
• ACOG (American College of Obstetrics and Gynecology): A professional association of obstetricians and gynecologists.
• Assisted reproductive technology (ART): Medical procedures to treat infertility that combine sperm and egg outside of the body. IVF is an example of ART.
• Asthenospermia: The medical diagnosis of a man whose sperm swims relatively slowly (reduced motility).
• Azoospermia: The medical diagnosis of a man whose semen contains no sperm.
• BBT (Basal body temperature): A woman’s resting body temperature. It rises approximately half a degree in response to ovulation.
• BFP: Colloquial term used for a positive pregnancy test, meaning “big fat positive.”
• BFN: Colloquial term used for negative pregnancy test, meaning "big fat negative."
• Bioavailability: A measure of how easily a drug can be utilized by the body.
• BMI (Body Mass Index): A measurement of body fat based on the ratio of weight to height.
• Calcium: A mineral that is essential for building bones and teeth in the developing fetus.
• Cervical Mucus: Mucus produced by the cervix. Its characteristics change throughout the menstrual cycle and can indicate when a woman is in her fertile window.
• Cervix: The opening to the uterus. Sperm must pass through the cervix and uterus to reach an egg.
• Conception: The moment a sperm fertilizes an egg.
• Corpus luteum: A progesterone producing structure located within the ovaries that forms from the follicle that releases an egg.
• D&C (Dilation and curettage): A medical procedure to remove tissue from inside the uterus. A D&C can be performed to diagnose and treat uterine conditions, to clear the uterus of pregnancy tissue after a miscarriage, or during an abortion.
• DHA (Docosahexaenoic Acid): An omega-3 fatty acid that is important for brain and eye development. It can be found in fatty fish or omega-3 supplemented dairy and eggs.
• Egg: The female reproductive cells produced in the ovaries. Also known as the ovum.
• Embryo: An early stage of human development. When an egg is fertilized, an embryo is created. It then grows, matures, and develops until it reaches a developmental milestone at 11 weeks gestation, when it becomes a fetus.
• Endometriosis: A condition where the endometrium (inner cells of the uterus) grow outside the uterus. Endometriosis can affect fertility and cause painful periods.
• Endometrium: The inner lining of the uterus. This layer thickens and sheds during menstruation. It is also the layer of the uterus where an embryo will implant.
• Estrogen: The primary sex hormone in women, mainly produced by the ovaries (follicles) and placenta. It helps to regulate the menstrual cycle. It is also present in men, controlling libido, sperm production, and other important sexual functions.
• Fallopian tube: The two tubes connecting the ovaries to the uterus, where sperm fertilize the egg. The tubes have little hairs inside (cilia) to help the egg travel from the ovary to the uterus.
• Fertile window: The time when a woman is most likely to conceive. It is the six days preceding and including the day of ovulation.
• Fertilization: The process by which a sperm and egg combine to form an embryo. During natural conception, this occurs in the fallopian tube.
• Folate: A B vitamin (B9) known to decrease the risk of neural tube defects. It refers to the class of folates found in foods and dietary supplements. This includes folic acid and MTHF folate.
• Folic acid: A synthetic form of folate used in food fortification programs in the US and found in prenatal vitamins. It is most effective at lowering the risk of neural tube defects in a developing embryo when taken one to three months before conception.
• FSH (Follicle Stimulating Hormone): A hormone produced in the brain that helps coordinate the menstrual cycle. It promotes the maturation of immature eggs inside the ovary during the first half of the menstrual cycle, from the onset of menstruation until ovulation.
• Gene: The building blocks of our DNA. They are passed from parent to child.
• Genetic carrier screening: A type of genetic testing done on parents, usually before they try to conceive, to identify risk factors for genetic disorders. These include spinal muscular atrophy and cystic fibrosis, among others.
• Genetic disorder: A disease resulting from a genetic mutation. Cystic fibrosis and spinal muscular atrophy are both genetic disorders.
• Gestational carrier (GC): Also known as a surrogate, a GC is a woman who carries a pregnancy for a couple who is unable to on their own. A GC usually does not have any genetic relation to the child she carries.
• Hemoglobin: The protein within red blood cells that binds oxygen and carries it throughout your body.  
• HCG (Human Chorionic Gonadotropin): A hormone made by the early embryo or placenta, hCG is the first detectable sign of pregnancy. hCG is what is detected by home pregnancy tests.
• Implantation: The process by which an embryo buries itself into the uterine wall. This usually occurs nine days after ovulation.
• IVF (In-vitro fertilization): IVF is the process of combining a sperm and egg outside of the body to treat infertility. IVF is a type of ART.
• Infertility: Inability to conceive after 12 months of unprotected sex.
• ICSI (Intracytoplasmic sperm injection): Fertilizing an egg by injecting a single sperm directly inside it.
• IUI (Intrauterine Insemination): A fertility intervention where sperm is deposited directly into the uterus.
• Iron: A mineral that is an essential component of hemoglobin.
• L-methylfolate (MTHF) folate: The active form of folate that your body uses. It is found in newer dietary supplements. It is most effective at lowering the risk of neural tube defects in a developing embryo when taken one to three months before conception.
• LH (Luteinizing Hormone): A hormone produced in the brain that coordinates the menstrual cycle and induces ovulation.
• LH surge: The steep rise in Luteinizing Hormone that precedes ovulation. This surge is detected by ovulation tests to identify a woman’s fertile window.
• Luteal phase: The second half of the menstrual cycle, from ovulation until the onset of the next menstrual cycle.
• Menopause: The cessation of menstrual periods.
• Menstrual cycle:  Cyclical changes in the female reproductive system that allow for pregnancy. This includes the building and shedding of the uterine lining, egg maturation, and ovulation, followed by either embryo implantation (if pregnancy occurs) or menstruation (if pregnancy does not occur). On average, this is 28 days.
• Menstruation: The cyclical shedding of the uterine lining, commonly known as a period.
• Miscarriage: A pregnancy loss that occurs before 20 weeks.
• Neural-tube: The embryonic precursor to the brain and spinal cord.
• Neural-tube defects: Developmental defects of the neural tube. These include spina bifida and anencephaly (the two most common types of neural tube defects). The incidence in the United States of these two types is 5.5 to 6.5 per 10,000 births.
• OBGYN: Abbreviation for the medical specialties of obstetrics and gynecology. Obstetrics covers pregnancy, childbirth, and the post-partum period. Gynecology covers the health of the female reproductive system.
• Oligomenorrhea: Infrequent or irregular periods.
• Oligospermia: The medical diagnosis of a man with low sperm count.
• Ovarian follicle: The fluid filled sac in the ovary that contains an egg and its associated support cells.
• Ovaries: The female sex organs. Equivalent to the male testes. Most women have two. They produce eggs (in a process known as oogenesis) and are connected to the uterus via the fallopian tubes.
• Ovulation: The release of a mature egg from an ovary. Usually occurs around day 14 of the menstrual cycle.
• Ovulation Test: At-home tests that detect when a woman is in her LH surge to identify her fertile window. Also known as ovulation predictor kits (OPKs).
• PCOS (Polycystic Ovary Syndrome): A hormonal disorder marked by irregular or absent menstrual periods, ovarian cysts, excess body hair, and difficulty getting pregnant.
• Post-partum: The period after childbirth.
• Pregnancy induced anemia: A condition brought on by pregnancy when blood does not have enough hemoglobin.
• Pregnancy test: At-home tests that determine if a woman is pregnant by detecting the presence of hCG in a woman’s urine.
• Prenatal: Before or during pregnancy. 
• Prenatal vitamins: Vitamins designed to be taken before, during, and after pregnancy to ensure that a pregnant woman is receiving enough nutrients to support her and a developing child.
• Primary Ovarian Insufficiency (POI): The loss of ovarian function before age 40.
• Progesterone: A female sex hormone produced by the ovaries (corpus luteum), adrenal glands, and placenta. It regulates the menstrual cycle and supports a pregnancy.
• Puberty: The onset and development of the capability of sexual reproduction.
• Semen: Fluid that contains sperm.
• Sexually Transmitted Infections (STIs): Also referred to as sexually transmitted diseases, STIs are infections spread by sex. They include chlamydia, herpes, gonorrhea, syphilis, HIV/AIDS, etc.
• Sperm: The male reproductive cell produced in the testes.
• TTC: A commonly used acronym for the phrase “trying to conceive.”
• Teratozoospermia: The medical diagnosis of a man with abnormally shaped sperm.
• Testes: The male reproductive organs. Equivalent to the female ovaries. They produce sperm.
• Testosterone: A male sex hormone. It is produced mainly by the testes. In men, it regulates sperm production, sexual arousal, the development of sexual reproduction, muscle development, and behavior. In women, testosterone helps to maintain bone mass and regulate sexual arousal.
• Tetrahydrocannabinol (THC): The component of marijuana that makes you feel high (psychoactive).
• Two week wait (TWW): The two weeks between ovulation and when you can take a pregnancy test.
• Uterus: Also known as a womb, this is where an embryo will develop during pregnancy. It is connected to the ovaries via the fallopian tubes. If you’re not pregnant, the lining (endometrium) sheds as your period.
• Varicocele: The enlargement of a vein in the scrotum.

Remember to always check with your healthcare provider about any information you see online. It’s always best to get clarification from a professional before moving forward with any lifestyle or dietary changes.

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