dictionary of reproductive medicine terminology

Unfamiliar language and the heavy use of acronyms can make discussions about infertility difficult to understand. Please use the following dictionary of reproductive medicine terminology to aid in your education about fertility care.


Human genetic material is arranged into structures called chromosomes. While most healthy individuals possess 46 chromosomes, additions or subtractions to this number can result in disease; this is known as “aneuploidy”. Aneuploidy among embryos is a major explanation behind the age-related decline in female fertility. 

Antimullerian Hormone (AMH)

The ovary produces antimullerian hormone and its blood levels correlate with the number of eggs that are remaining in the ovary. AMH is used clinically as an assessment of ovarian reserve.  

Antral Follicle Count

Small ovarian follicles, spherical cyst-like structures that each contain an immature egg, can be directly visualized by ultrasound. The total number of these follicles, termed the antral follicle count, can be used to predict ovarian reserve and response to treatment.

Assisted Reproductive Technology (ART)

Assisted Reproductive Technology (ART) is any fertility procedure that involves removal of oocytes (eggs) from the body. The most common ART is in vitro fertilization (IVF). Others include ZIFT (zygote intrafallopian transfer), GIFT (gamete intrafallopian transfer) and in vitro maturation (IVM).


The stage at which an embryo will implant into the uterus. A blastocyst or “blast” is typically reached after 5-6 days of growth and composed of approximately 100 cells.

Clomiphene Citrate (Clomid)

Clomiphene citrate (Trade name: Clomid or Serophene) is an oral medication commonly used in basic infertility treatments. Clomid potentiates ovarian follicle development and is often employed for women who do not ovulate regularly (PCOS) or for couples with unexplained infertility.

Controlled Ovarian Hyperstimulation (COH)

Controlled ovarian hyperstimulation (COH)  is the process whereby medication (pharmacologic preparations of FSH and LH) is used to develop many eggs. In the sequence of events of an IVF cycle, COH immediately precedes egg retrieval. 

Diminished Ovarian Reserve (DOR)

Diminished ovarian reserve (DOR) refers to the state of the ovary as it nears the end of its reproductive lifespan.  The ovary holds a finite amount of eggs which are continuously depleted as a woman ages. When this number reaches a critically low threshold, fertility is significantly impacted and a diagnosis of “DOR” is made. 

Donor Eggs

Oocytes (eggs) can be harvested from a third party individual and used by a infertility patient to achieve pregnancy. In a common scenario, donor eggs are coupled with a husband’s sperm and the resulting embryos are transferred into the uterus of the wife. Eggs can originate from an anonymous or known donor.

Donor Sperm

Donor sperm is employed in several different reproductive medicine scenarios. These include: a) couples where the male partner has an extremely low sperm count b) women without a male partner and c) couples where the male partner carries a genetically-linked disease. Donor sperm can be either anonymous (from a sperm bank) or directed (from a known individual).

Egg Freezing

Egg freezing (oocyte cryopreservation) involves surgically harvesting eggs from the ovary and then freezing them for use in the future. The treatment takes place over several weeks and begins with medical stimulation of the ovaries.


An embryo is the earliest stage of human development. After fertilization between an egg and sperm takes place, an embryo results and begins to grow rapidly through cell division. In IVF, the most advanced stage of embryo development is termed the blastocyst.

Embryo Transfer (ET)

Embryo transfer is one of the last steps in an IVF cycle. After approximately 3-5 days of development in the laboratory, embryos are placed into the upper part of the uterus by passing a small catheter (a thin straw-like device) through the cervix. This is a brief outpatient procedure that does not require anesthesia.


Endometriosis results when implants of menstrual tissue seed and grow in various areas of the pelvic and/or abdominal cavities. Endometriosis interferes with many steps in the reproductive process and can be responsible for such things as poor egg quality or implantation failures.


A follicle is a fluid-filled spherical structure arising from the ovary. Each follicle (the ovary typically has many at any given point in time) consists of a single oocyte (egg) surrounded by many cells and fluid that support the egg’s development. Monitoring of follicular numbers and growth by ultrasound is frequently employed in fertility therapies.  

Follicle Stimulating Hormone (FSH)

Follicle stimulating hormone (FSH) originates from the pituitary gland in the brain. Its primary role is to act as the monthly signal to the ovary to develop an egg for ovulation. Pharmacologic preparations of FSH can achieve the development of more than one egg and are employed in such procedures as superovulation and IVF.

Frozen Embryo Transfer (FET)

Some IVF cycles result in the creation of an excess number of embryos. In this situation, embryos can be cryopreserved (frozen) for future use. When ready (in some situations after many years), embryos are thawed and transferred into the uterus to attain pregnancy.

Gamete Intrafallopian Transfer (GIFT)

GIFT is an assisted reproductive technology where gametes from both partners (eggs and sperm) are placed into the woman’s fallopian tube to allow fertilization to take place. Because IVF has become so successful, GIFT has become a relatively uncommon procedure.


The gonadotropins, FSH and LH, are hormones released from the pitutiatry gland that signal the ovary to produce an egg. In the setting of fertility treatments, pharmacologic preparations of gonadotropins are used to develop multiple follicles. 

Hysterosalpingogram (HSG)

A hysterosalpingogram is an X-ray study performed in the outpatient hospital setting where radio-opaque dye is injected into the uterus. Dye outlines the contour of the endometrial cavity (inside of the uterus) and flows through the fallopian tubes. This helps define the anatomy of your uterus and demonstrate functionality of your tubes.


A hysterosonogram, also known as a saline infusion sonogram (SIS), is a brief office procedure that is used as an adjunct to conventional pelvic ultrasound. Under direct ultrasound visualization, saline solution is infused into the uterus, allowing the physician to evaluate the cavity for any pathology (such as polyps or fibroids).

Intracytoplasmic Sperm Injection (ICSI)

Intracytoplasmic sperm injection is a technique whereby a single sperm head is injected into a single egg to facilitate fertilization. It is accomplished through the use of microscopic needles under direct visualization. 

Intrauterine Insemination (IUI)

This is an office procedure that attempts to heighten the probability of pregnancy by concentrating the healthiest sperm in the upper part of the uterus. After collection of an ejaculate, a semen sample is processed in our laboratory to remove the unwanted components of the seminal plasma. A small concentrated volume of sperm is then deposited into the uterus via a catheter (thin straw-like device).

In Vitro Fertilization (IVF)

In vitro fertilization is a 6-8 week fertility treatment that currently offers the best overall chance for conception. The treatment begins with pharmacologic stimulation of the ovaries to promote the development of many eggs. After egg collection via a minor surgical procedure, fertilization takes place in the laboratory. The final step is the transfer of embryos into the uterus to allow natural implantation to occur.

In Vitro Maturation (IVM)

IVM is an experimental treatment approach which involves many of the same steps as IVF but avoids the ovarian hyperstimulation component. It is most successful for women who have more than an average amount of small, undeveloped follicles in their ovaries (polycystic ovaries).  


A karyotype is a visual examination of chromosomes, the structures that contain a human being’s genetic material. Typically, a healthy individual has a total of 46 chromosomes. A karyotype is customarily reported as “46 XX” (denoting a female) or “46 XY” (denoting a male).  

Luteinizing Hormone (LH)

In a normal menstrual cycle, luteinizing hormone (LH) is made by the pituitary gland and aids FSH in the development of a mature egg for ovulation. In fertility therapy, pharmacologic preparations of LH are used in conjunction with FSH to facilitate multiple egg development. 

Male Factor

Male factor encompasses all causes of infertility attributable to abnormalities in sperm production or function. A male factor can be found in approximately 50% of couples with infertility.

Ovarian Hyperstimulation Syndrome (OHSS)

A medical complication associated with pharmacologic stimulation of the ovaries. OHSS is characterized by variable amounts of fluid and electrolyte imbalances. The mild form is common and typically benign, however more severe forms occur and can be serious.

Ovarian Reserve

An estimate of the number and quality of eggs remaining in the ovaries. Ovarian reserve decreases with age.

Ovulation Induction

For women who do not ovulate regularly, medications can be used to restore this process. Typically, induction of ovulation is attained with the use of either oral or injectable medication taken for a period of 5-10 days at the beginning of a menstrual cycle.  

Ovulatory Dysfunction

For most women, ovulation occurs on a monthly basis and is the end result of a complex system of hormonal signaling. The slightest abnormality in this system may cause failure of ovulation to occur. This is known as “ovulatory dysfunction”.

Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS) is a common hormonal imbalance characterized by irregular periods and excessive hair growth. PCOS patients are also commonly overweight and have disturbances in glucose metabolism (pre-diabetes)

Preimplantation Genetic Diagnosis (PGD)

The process whereby genetic information about an embryo is obtained before it is transferred into the uterus for implantation. Indications for PGD include a family history of genetically-linked diseases.   

Preimplantation Genetic Screening (PGS)

Preimplantation genetic screening (PGS) is an identical procedure to PGD, however the goal here it to assess the embryo for aneuploidy, a major factor behind the age-related decrease in female fertility.

Premature Ovarian Failure (POF)

Premature ovarian failure describes a condition where the ovaries cease to function earlier in one’s life than expected. In contrast to menopause which is typically experienced around age 50-52, POF is defined as loss of ovarian function prior to the age of 40.

Recurrent Pregnancy Loss (RPL)

Overall, 15% of early pregnancies end in spontaneous miscarriage. When an individual experiences two to three early pregnancy losses, a diagnosis of recurrent pregnancy loss is given.

Semen Analysis (SA)

Semen analysis is an essential part of any infertility evaluation. After home or office collection of an ejaculate, semen is evaluated for the concentration, motility and morphology. These parameters are predictive of chances of conception.

Sex Selection

Sex selection, also known as family balancing or gender selection, is the process whereby reproductive medicine technology (preimplantation genetic diagnosis or sperm sorting) is employed to heighten the probability of giving birth to a particular gender. Sex selection can be the sole reason for a couple to undergo fertility treatment or may be a secondary goal of therapy.

Superovulation (SO)

When ovulating more than one egg may heighten the probability of pregnancy superovulation (SO) is often employed. SO involves daily injections of gonadotropin medication and, to maximize success, is often coupled with IUI.


Surrogacy is a form of reproduction where a third party individual contracts to carry a pregnancy for an infertility couple. A gestational carrier is a type of surrogate whose pregnancy is the genetic offspring of the couple intended to receive the newborn.

Transvaginal Oocyte Aspiration (TVOA)

TVOA is the step in IVF where eggs are removed from the ovary. Using ultrasound guidance, a small needle is passed through the upper portion of the vagina and into each ovary. Under suction pressure the contents of the follicle (cyst like structures housing the egg) are collected. This is an outpatient procedure done under anesthesia.

Tubal Factor

The uterus has two fallopian tubes, one on each side. Their responsibilities include egg pickup after ovulation and the transport of the embryo to the uterus for implantation. Any abnormality in the structure or function of the tubes can result in infertility and is known as “tubal factor”.

Tubal Reanastomosis

Tubal reanastomosis is a surgical attempt to repair fallopian tubes that have previously undergone a sterilization procedure.   Many variables are factored into the prognosis for success including patient age, type of previous sterilization and length of the tube upon completion of the reanastomosis.

Unexplained Infertility

The diagnosis given to couples who, after completion of all standard infertility evaluations, have no identifiable reproductive problems. Because an exact diagnosis cannot be made, recommended therapy is empiric.

Uterine Factor

Uterine factor refers to any infertility problem that involves pathology of the uterus. Common conditions included in this diagnosis are polyps, fibroids and adenomyosis.

Uterine Mapping

Also known as a mock embryo transfer, this office procedure simulates the events that will take place on the real embryo transfer day. Information that is gathered from this procedure includes assessing the size and orientation of the uterine cavity and the ease or difficulty in which the transfer catheter is inserted.


A laboratory technique used to cryopreserve (freeze) reproductive tissues. In comparison to traditional techniques where the freezing process takes several minutes to complete, vitrification occurs in seconds.

X and Y Chromosomes

Human genetic material is arranged into structures called chromosomes. Two of these, known as the X and Y chromosomes, pair together to determine the sex of the individual. When the pair of sex chromosomes is made up of two X chromosomes, a female results. When the pair consists of one X and one Y chromosome a male results.


A zygote is the earliest form of life when a single cell is made up of genetic material from the egg and the sperm. A zygote rapidly divides into 2 cells and this is followed by the development of a multi-celled embryo.

Zygote Intrafallopian  Transfer (ZIFT)

ZIFT is an assisted reproductive technology where the earliest form of an embryo, a zygote, is surgically placed into the woman’s fallopian tube. This allows the embryo to develop in vivo (in the body) and migrate towards the uterus for implantation. Because IVF has become so successful, ZIFT has become a relatively uncommon procedure

Three dimensional ultrasound image of human fetus in utero at 16 weeks.