Skip to main content

IVF Glossary

Understanding IVF terminology can feel overwhelming. This glossary explains common terms you will encounter on your journey.

AFC
Antral Follicle Count, an ultrasound measurement of small follicles visible in both ovaries, used to estimate ovarian reserve.
Agonist Protocol
IVF stimulation protocol using GnRH agonist (e.g., Lupron) to suppress the pituitary gland before and during stimulation.
AMH
Anti-Mullerian Hormone, a blood test measuring ovarian reserve. Higher values generally indicate more eggs remaining.
Antagonist Protocol
IVF stimulation protocol using GnRH antagonist medications to prevent premature ovulation during the stimulation phase.
Baseline Ultrasound
Transvaginal ultrasound performed early in a cycle to check for cysts and count antral follicles before starting medications.
Beta (hCG)
Blood test measuring levels of the pregnancy hormone human chorionic gonadotropin (hCG). A rising beta can be an early pregnancy signal that your clinic interprets in context.
Blastocyst
A Day 5 or Day 6 embryo that has developed to the stage with a fluid-filled cavity and two distinct cell groups. Many clinics use blastocyst development as one factor when discussing transfer timing.
Cryopreservation
The process of freezing eggs, sperm, or embryos at ultra-low temperatures for future use. Ask your clinic how vitrification outcomes apply to your lab and case.
Day 3 Transfer
Embryo transfer performed three days after egg retrieval, when embryos are at the 6-8 cell cleavage stage.
Day 5 Transfer
Embryo transfer at the blastocyst stage, five days after egg retrieval. Clinic recommendations vary by embryo development, history, and treatment plan.
E2 (Estradiol)
Estrogen hormone measured via blood test during stimulation to track follicle growth and guide medication dosing.
Ectopic Pregnancy
A pregnancy that implants outside the uterus, most commonly in a fallopian tube. Requires prompt medical treatment.
Embryo Transfer (ET)
The procedure that places one or more embryos into the uterus via a thin catheter. Ask your clinic what discomfort, medication, or preparation to expect.
Endometriosis
A condition where tissue similar to the uterine lining grows outside the uterus. Can affect fertility and is common among IVF patients.
ERA Test
Endometrial Receptivity Analysis, a biopsy-based test to determine the optimal window for embryo transfer in patients with repeated implantation failure.
FET
Frozen Embryo Transfer, a cycle in which previously frozen and thawed embryos are transferred to the uterus.
FSH
Follicle Stimulating Hormone. Used as a blood test marker for ovarian reserve, and also the main ingredient in injectable stimulation medications.
Gardner Grading
Blastocyst appearance scoring system combining expansion (1-6), inner cell mass (A-C), and trophectoderm (A-C). Ask your clinic how they interpret a specific grade.
Gestational Carrier
A person who carries a pregnancy using embryos created by another couple or individual. Distinct from a traditional surrogate.
GnRH Agonist
Medication (such as Lupron/leuprolide) used to suppress the body's natural hormone cycle before or during IVF stimulation.
GnRH Antagonist
Medication (such as Ganirelix or Cetrotide) used during stimulation to prevent the body from releasing eggs prematurely.
hCG Trigger
An injection of human chorionic gonadotropin given approximately 36 hours before egg retrieval to trigger final egg maturation.
ICSI
Intracytoplasmic Sperm Injection, a fertilization technique where a single sperm is injected directly into an egg. Used for male factor infertility or low fertilization history.
Implantation
The process by which an embryo attaches to the uterine lining. Successful implantation is required for pregnancy to continue.
IUI
Intrauterine Insemination, a less invasive fertility treatment where washed sperm are placed directly into the uterus around ovulation.
LH
Luteinizing Hormone. Naturally triggers ovulation. In IVF, a premature LH surge is suppressed with antagonist or agonist medications.
Luteal Phase
The phase after ovulation or retrieval when progesterone supports the uterine lining. In IVF, progesterone supplementation is typically required.
Mosaic Embryo
An embryo containing a mix of chromosomally normal and abnormal cells, as detected by PGT-A. Transfer decisions are made case by case with your clinic.
OHSS
Ovarian Hyperstimulation Syndrome, a potential complication of stimulation where the ovaries become swollen and fluid can leak into the abdomen. Ranges from mild to severe.
PGT-A
Preimplantation Genetic Testing for Aneuploidy, screens embryo biopsy samples for chromosomal findings before transfer. Ask your clinic how results affect selection and counseling.
PGT-M
Preimplantation Genetic Testing for Monogenic disorders, screens embryos for specific inherited single-gene conditions.
Progesterone
Hormone involved in preparing and maintaining the uterine lining after ovulation or retrieval. Many IVF protocols supplement it by injection, suppository, or vaginal gel; timing is clinic-specific.
Retrieval
Egg retrieval procedure, typically transvaginal under light sedation. Follicles are aspirated with a needle to collect mature eggs.
RPL
Recurrent Pregnancy Loss, defined as two or more consecutive pregnancy losses. Often prompts investigation into chromosomal, anatomical, or immune factors.
Stim
The stimulation phase of an IVF cycle during which injectable gonadotropin medications are used to grow multiple follicles.
Thin Lining
A uterine lining (endometrium) that measures below a clinic-specific target. Your care team can explain whether medication or protocol changes apply.
Transfer
Short for embryo transfer, the procedure that places embryo(s) into the uterus.
Trigger Shot
Final injection (hCG or Lupron) administered approximately 36 hours before egg retrieval to complete egg maturation.
TWW
Two Week Wait, the approximately 10-14 day period between embryo transfer and the first pregnancy blood test. Often the most emotionally intense phase.
Uterine Factor
Structural or anatomical conditions of the uterus (such as fibroids, polyps, or septum) that may affect implantation or pregnancy.
Vitrification
Ultra-rapid flash-freezing technique used to cryopreserve eggs and embryos. Lab outcomes vary, so ask your clinic about its thaw and survival data.

Missing a term?

Let us know and we will add it to help others.

Contact Us