A

AFC (Antral Follicle Count)
An ultrasound measurement that counts the small, resting follicles visible in both ovaries at the start of a cycle. Each follicle represents a potential egg for that cycle. Used alongside AMH to assess ovarian reserve. See: Before Your Cycle Starts
AMH (Anti-Müllerian Hormone)
A blood test that measures a hormone produced by ovarian follicles. Reflects ovarian reserve — how many eggs remain. Higher levels suggest more eggs available; lower levels suggest fewer. One of the two most important numbers in the egg freezing process. See: Before Your Cycle Starts
Anesthesia (MAC)
Monitored anesthesia care — the form of intravenous sedation used during egg retrieval. Produces full unconsciousness for the duration of the procedure (typically 5–10 minutes). Different from local anesthesia or light sedation. See: Egg Retrieval
Antagonist (GnRH Antagonist)
A medication (Cetrotide or Ganirelix) added mid-cycle during stimulation to prevent premature ovulation. Suppresses the LH surge that would trigger the follicles to release eggs before retrieval. Taken as a daily morning injection once follicles reach a certain size. See: Injections and Monitoring

B

Blastocyst
A fertilized egg that has developed for approximately 5–6 days to the stage where it's ready for transfer to the uterus. Not all fertilized eggs develop to blastocyst stage — this is one step in the funnel between egg retrieval and a potential pregnancy.
Baseline appointment (Day 2 Start)
The monitoring appointment on Day 2 or Day 3 of the menstrual cycle that confirms the ovaries are suppressed and ready to start stimulation. Bloodwork and ultrasound. If everything looks clear, injections begin that evening. Cycle fees are due at this appointment at NYU Langone. See: Before Your Cycle Starts

C

Cetrotide
A GnRH antagonist medication used to prevent premature ovulation during stimulation. Equivalent to Ganirelix — one or the other is prescribed, not both. See: Medications
Cryopreservation
The process of freezing biological material — in this context, eggs — for long-term storage. Modern egg cryopreservation uses vitrification rather than slow-freeze methods. Eggs are stored in liquid nitrogen at –180°C. See: What Is Egg Freezing?
Cryostorage
The ongoing storage of frozen eggs. At NYU Langone, managed through the Prelude Cryopreservation portal. Annual fee: $1,250. Eggs can be stored indefinitely. See: What It Actually Costs

D

Day 1
The first day of full menstrual flow — not spotting or staining. Full flow before midnight counts as Day 1. The action on Day 1 is to call the clinic to schedule the Day 2 monitoring appointment. See: Before Your Cycle Starts
Day 2
The second day of full menstrual flow. The baseline appointment happens on Day 2 (or Day 3 if the period arrives at night). The stimulation cycle officially begins here if bloodwork and ultrasound are clear. See: Before Your Cycle Starts

E

Embryo
A fertilized egg. Created when an egg and sperm are combined. Embryo freezing (as opposed to egg freezing) requires a sperm source at the time of retrieval. Embryos can be tested for chromosomal abnormalities before transfer. See: What Is Egg Freezing?
Endometrium
The lining of the uterus. Where an embryo implants during a successful pregnancy. Not directly relevant to egg freezing — becomes relevant during a future transfer cycle.

F

Follicle
A fluid-filled sac in the ovary that contains a developing egg. Normally one follicle matures per cycle. Stimulation medications cause multiple follicles to develop simultaneously. Measured by ultrasound during monitoring — size in millimeters indicates readiness. Around 18–20mm is considered mature. See: Injections and Monitoring
Follicle count
The number of follicles visible on ultrasound during monitoring. Not the same as egg count — not every follicle contains a mature egg. The follicle count during stimulation is always higher than the final number of frozen eggs. See: Injections and Monitoring
FSH (Follicle-Stimulating Hormone)
A hormone that stimulates follicle development. The main active ingredient in Gonal-F and Follistim — the gonadotropin medications used in the first phase of stimulation. See: Medications

G

Ganirelix
A GnRH antagonist equivalent to Cetrotide — one or the other is prescribed, not both. Used to prevent premature ovulation mid-cycle. See: Medications
GnRH Antagonist
A category of medication (Cetrotide or Ganirelix) that suppresses the LH surge to prevent premature ovulation during stimulation. Added mid-cycle, taken as a morning injection until the trigger shot. See: Injections and Monitoring
Gonal-F
A gonadotropin (FSH) medication used in the stimulation phase. Equivalent to Follistim — same drug, different manufacturer. One or the other is prescribed, not both. Given via a pre-filled pen. See: Medications
Gonadotropins
The category of stimulation medications — FSH (Gonal-F or Follistim) and HMG (Menopur) — that cause the ovaries to develop multiple follicles simultaneously. The main daily injection during the stimulation phase. See: Injections and Monitoring

H

hCG (Human Chorionic Gonadotropin)
The hormone in Ovidrel (the trigger shot). Mimics the natural LH surge that causes eggs to release. Triggers final egg maturation 34–36 hours before retrieval. See: The Trigger Shot
HMG (Human Menopausal Gonadotropin)
The active ingredient in Menopur. A gonadotropin that contains both FSH and LH activity, used alongside FSH medications in the stimulation phase. See: Medications

I

IVF (In Vitro Fertilization)
A fertility treatment where eggs are retrieved, fertilized with sperm outside the body, and transferred to the uterus. Not the same as egg freezing — IVF involves fertilization immediately after retrieval. This site covers egg freezing only. See: What Is Egg Freezing?

L

LH (Luteinizing Hormone)
A hormone that triggers ovulation — the release of a mature egg from the follicle. The GnRH antagonist suppresses the LH surge during stimulation to prevent premature ovulation. The trigger shot mimics or induces the LH surge at the controlled time.
Lupron (Leuprolide Acetate)
One of two trigger shot options. Triggers the body's own LH surge rather than adding hCG directly. Often used when OHSS risk is higher. Next period arrives approximately one week after retrieval (versus two weeks with Ovidrel). See: The Trigger Shot

M

Mature egg (MII oocyte)
An egg that has completed the final stage of development required for freezing or fertilization. Only mature eggs can be frozen. The number of mature eggs is always lower than the total eggs retrieved, which is why the frozen count differs from the follicle count. See: Egg Retrieval
Menopur
A gonadotropin (HMG) medication containing FSH and LH activity. Typically used alongside Gonal-F or Follistim in the stimulation phase. Given as a subcutaneous injection. The HEART Rx Initiative offers manufacturer discounts for qualifying patients. See: Medications
Morning monitoring
Clinic appointments during the stimulation phase — bloodwork and ultrasound — that track follicle development and hormone levels. Happen between 7–9am, seven days a week, typically on Days 5, 8, and 10 of stimulation (variable). See: Injections and Monitoring

O

OHSS (Ovarian Hyperstimulation Syndrome)
A condition where the ovaries over-respond to stimulation medications. Mild OHSS — bloating, discomfort — is relatively common. Severe OHSS is rare but serious. Risk factors include high AMH, high follicle count, and young age. Lupron trigger may reduce risk compared to Ovidrel. Contact the clinic if experiencing rapid bloating or significant weight gain. See: Injections and Monitoring
Oocyte
The medical term for egg. Oocyte cryopreservation = egg freezing. An unfertilized oocyte is what's frozen in egg freezing. Once fertilized, it becomes an embryo. See: What Is Egg Freezing?
Ovarian reserve
The number and quality of eggs remaining in the ovaries. Declines with age. Assessed using AMH (blood test) and AFC (ultrasound). A key factor in determining protocol and realistic expectations for a cycle. See: Before Your Cycle Starts
Ovarian torsion
A serious complication where enlarged ovaries twist on their own blood supply — requires emergency surgery. Risk increases significantly when ovaries are enlarged from stimulation. The reason high-impact exercise is restricted from Day 5 through the post-retrieval period. See: Lifestyle Restrictions
Ovidrel
The most common trigger shot — contains hCG in a pre-filled pen. Triggers final egg maturation and release approximately 36 hours later. Next period arrives approximately two weeks after retrieval. Not bought until the nurse confirms which trigger type is needed. See: The Trigger Shot

P

Prelude Cryopreservation
NYU Langone's billing partner for cryostorage. Patients receive a welcome email within two weeks of retrieval and set up an account to manage annual storage payments and disposition consents. See: What It Actually Costs
Protocol
The specific medication plan for a cycle — which drugs, at what doses, on which days. Personalized based on AMH, AFC, age, and other factors. Given at the Day 2 appointment and adjusted throughout the cycle based on monitoring results.

S

SART (Society for Assisted Reproductive Technology)
A professional organization that publishes outcome data for member fertility clinics at sart.org. Data is self-reported and lags by 1–2 years, but provides the best publicly available comparison point for clinic outcomes. See: How to Choose a Clinic
Stimulation phase
The 10–14 day period of daily hormone injections that cause multiple follicles to develop simultaneously. Begins on Day 2 or 3 of the cycle and ends with the trigger shot. Requires morning monitoring appointments and daily injections. See: Injections and Monitoring
Subcutaneous injection
An injection into the fatty layer just beneath the skin — not into muscle. All egg freezing injections are subcutaneous, typically given in the abdomen. The needle is small; most people find them manageable after the first few days.

T

Trigger shot
The final injection of the stimulation cycle — Ovidrel (hCG) or Lupron (leuprolide), or both — that triggers final egg maturation and initiates release. Given at a precise time assigned by the nurse. Retrieval is scheduled exactly 34–36 hours later. The most time-sensitive injection in the process. See: The Trigger Shot

U

Transvaginal ultrasound
An ultrasound performed with a probe inserted vaginally — provides clearer images of the ovaries and follicles than an external ultrasound. Used at the baseline appointment, during monitoring to measure follicle growth, and to guide the needle during egg retrieval.

V

Vitrification
The ultra-rapid freezing method used to preserve eggs. Eggs are exposed to cryoprotectants (which replace water in the cell), loaded into storage straws, and cooled at thousands of degrees per minute — turning cell contents into a glass-like solid rather than allowing ice crystals to form. Significantly better survival rates than older slow-freeze methods. The current standard for egg cryopreservation. See: What Is Egg Freezing?