Learn
Glossary
Plain-language definitions of common fertility terms. Each entry links to related pages where you can read more.
- Blastocyst
A blastocyst is an embryo that has developed for about five to six days after fertilisation, reaching a stage with a fluid-filled cavity. Embryos are sometimes grown to this stage before transfer or freezing.
Also known as: Day-5 embryo
Reviewed
- Embryo transfer
Embryo transfer is the step in IVF where an embryo is placed into the uterus using a thin catheter. It is usually a short outpatient procedure, and often only one embryo is transferred to reduce the chance of a multiple pregnancy.
Reviewed
- Frozen embryo transfer (FET)
A frozen embryo transfer (FET) is a procedure where an embryo that was frozen in a previous cycle is thawed and transferred to the uterus. It lets people use stored embryos without repeating ovarian stimulation.
Also known as: FET
Reviewed
- Luteal phase
The luteal phase is the part of the menstrual cycle after ovulation and before a period. In fertility treatment, medicines such as progesterone are sometimes used to support this phase, known as luteal-phase support.
Reviewed
- Ovarian hyperstimulation syndrome (OHSS)
OHSS is a complication of ovarian stimulation where the ovaries over-respond to fertility medication. It is usually mild but can occasionally be serious, so clinics monitor for it and advise on warning signs.
Also known as: OHSS
Reviewed
- Ovarian reserve
Ovarian reserve refers to the number of eggs remaining in the ovaries. It is estimated using tests such as AMH and antral follicle count, but it does not measure egg quality or guarantee a pregnancy.
Reviewed