We try to keep things simple, but sometimes, we have to use medical lingo to be as accurate as possible. This glossary is here as a reference, just in case we ever use a phrase that’s not familiar to you. Anti-Müllerian Hormone (AMH)

Anti-Müllerian hormone (AMH)

AMH is a protein hormone produced by cells inside the ovarian follicles. The level of AMH in the blood can help doctors estimate the number of follicles inside the ovaries. A typical AMH level for a fertile woman is 1.0–4.0 ng/ml.


This term refers to the presence of an abnormal number of chromosomes in a cell, like an egg. Genetic abnormality in an embryo may lead to no implantation, miscarriage, or congenital disorders.

Antral follicle count (AFC)

An antral follicle count is performed by a doctor during an ultrasound. After visualizing the ovaries, the doctor can count the “activated” follicles, and use that number to estimate her total ovarian reserve.


This term refers to freezing biological material, such as a cell, tissue, or organism, in order to protect it from damage or aging. When biological material is frozen at a low enough temperature, all activity stops, including the activity leading to cell death or DNA degradation, and therefore the material is preserved.


Generally, a “cycle”—like a “menstrual cycle”—refers to the approximately 28-day period during which a woman’s body prepares for ovulation, releases an egg, waits for fertilization, and sheds the uterine lining if fertilization does not occur (learn more). Each “cycle” represents one chance at pregnancy, or one menstrual period if a woman is not trying to conceive.
In the world of reproductive medicine, “cycle” means one round of treatment. An egg freezing cycle refers to the approximately 2-week period during which a woman is taking ovary-stimulating medication and being monitored by a physician, and which culminates in the egg retrieval procedure.

Egg quality

Egg quality refers to whether an egg is genetically “normal” (euploid) or abnormal (aneuploid). As women age and the eggs inside their bodies are inevitably exposed to damaging influences, a higher and higher percentage of their eggs become abnormal. A high percentage of abnormal eggs can lead to infertility, miscarriage, or genetic disorders such as Down syndrome.

Egg quantity

Egg quantity refers to the number of follicles, or potential eggs, in a woman’s ovaries. Though born with 1–2 million egg follicles, a woman loses upwards of 1,000 eggs per month until menopause, with the rate of loss increasing after 35. Low egg quantity can lead to infertility.


This term refers to the presence, in an organism, of the proper of chromosomes. Euploid eggs are genetically normal.


Fertility refers to the ability to conceive a child. For a woman, this includes having an adequate supply of healthy eggs, a normal hormonal balance, and healthy reproductive organs.


Inside the ovaries, there are fluid-filled pockets called “follicles” that hold the eggs, one egg per follicle. The follicles also produce estrogen, which leads to ovulation, and progesterone, which preps the body for a possible pregnancy. Follicles typical remain “sleeping” (in their “primordial” state) until they’re activated at the beginning of the menstrual cycle; though a number of follicles are activated in any given cycle, only one egg will mature and be released during ovulation. The number of follicles activated in an ovary at the beginning of a cycle can indicate a woman’s ovarian reserve (see “Antral follicle count”).


Infertility is a disease of the reproductive system, defined by physicians as the inability to get or stay pregnant after 12 months of regular, unprotected sex. Being diagnosed as infertile doesn’t mean a woman can’t get pregnant—it just means something is preventing her body from getting pregnant on its own. Experts estimate that 1 in 8 women experience infertility; for women over 35, that number jumps to 1 in 3.

In vitro fertilization (IVF)

“In vitro,” a Latin phrase, translates literally to “in glass”—or, in other words, in a test tube, Petri dish, or other setting outside the body. In vitro fertilization is the process of using sperm, collected from a male partner, to fertilize an egg, retrieved from a female partner, in a laboratory; the fertilized egg is then allowed to develop for three to six days (becoming a blastocyst) before it’s transferred back into the woman’s body. IVF was originally developed as a way to achieve pregnancy for women with blocked Fallopian tubes, but is now used to treat infertility caused by a variety of factors, both male and female.

Typically, in order to provide the best chance at success (pregnancy), in vitro fertilization follows a process of controlled ovarian stimulation—see “Stimulation” for more details.


Menopause is the end of a woman’s reproductive life, the point at which her menstrual period ceases. This typically occurs around age 51. (connect this back to egg quantity – i.e. menopause occurs when women have no more meaningful supply of eggs remaining?)


Both of these terms refer to egg cells in various stages of maturation.

Oocyte cryopreservation

This is the “technical” term for egg freezing. Oocytes are egg cells, and “cryopreservation” means “to preserve by freezing.” (See “cryopreservation.”)

Ovarian reserve

This term refers to the ovaries’ capacity to provide healthy eggs that are able to be fertilized. As women age, their egg quality and quantity decrease; both of these factors affect ovarian reserve. “Diminished ovarian reserve” refers to the loss of this capacity, either due to age, injury, or disease.


In the context of reproductive medicine, stimulation refers to the use of hormonal medications to promote the ovaries to produce multiple mature eggs in a single cycle, as opposed to the single egg usually produced.


“Thawing,” in the context of egg freezing, refers to the controlled warming of a previously frozen egg in order to fertilize it.


Vitrification is a “flash freezing” technique that cools cells very quickly to a temperature of -196º Celsius, or about -320º Fahrenheit. Because the freezing happens so fast, the frozen cells become “glass-like,” or “vitrified,” minimizing the chance that the water inside the cells will form damaging ice crystals. This is especially important for egg freezing, since eggs (as opposed to other things we might freeze, like sperm) are mostly water. Studies have demonstrated that vitrification is superior to any other method of egg freezing, including slow freezing.


We understand you might have a lot of questions. That’s a good thing! We’ve collected a few of the most frequently asked questions for reference here, but if there’s something we haven’t covered, the healthcare team is just a phone call away.

Studies say

Cryopreservation, fertility preservation, and egg freezing have been researched by physicians and other experts for decades. This list includes some of the most enlightening and important studies published in the field of reproductive medicine.


We try to keep things simple, but sometimes, we have to use medical lingo to be as accurate as possible. This glossary is here as a reference, just in case we ever use a phrase that’s not familiar to you.

Forms & resources

Current and prospective patients can find paperwork and resources for medication, insurance, and more here.

Fertility statistics by age

If you’ve heard it once, you’ve heard it a thousand times—age is the most important factor in fertility. But what does that really mean?