Fertility Glossary

12 terms explained in plain language. Every definition sourced from medical authorities (HFEA, NHS, WHO, Cleveland Clinic).

AMH (Anti-Müllerian Hormone)

AMH blood test estimates how many eggs remain. Normal range: 1.0-3.0 ng/mL. It measures egg quantity, not quality. It doesn't predict fertility (Cleveland Clinic).

Blastocyst

A blastocyst is a 200-300 cell embryo at day 5-6 after fertilisation. Blastocyst transfer in IVF allows better embryo selection and supports single embryo transfer.

Egg Donation

Egg donation uses a donor's eggs for IVF when a patient's own eggs aren't viable. 82,373 cycles in Europe in 2019. Spain performs 43% of them.

Egg Freezing (Oocyte Cryopreservation)

Egg freezing preserves fertility for the future using vitrification. HFEA: patients under 38 typically collect 7-14 eggs per cycle. UK total cost: £7,000-£8,000.

Frozen Embryo Transfer (FET)

Frozen embryo transfer skips stimulation and egg collection, using embryos from a previous IVF cycle. 43% of all UK embryo transfers were frozen in 2021. Birth rates comparable to fresh.

ICSI (Intracytoplasmic Sperm Injection)

ICSI injects a single sperm directly into an egg. Used for male factor infertility. Success rates are similar to standard IVF (HFEA).

IUI (Intrauterine Insemination)

IUI places washed sperm directly in the womb. Simpler and cheaper than IVF, but success rates are about a third of IVF per cycle (HFEA).

IVF (In Vitro Fertilisation)

What IVF is, how it works step by step, and success rates by age, with data from HFEA 2021. Birth rates range from 33% (under 35) to 4% (over 43).

Live Birth Rate

The live birth rate measures cycles resulting in a living baby. The only IVF metric that truly matters. HFEA 2021: 33% for under-35s, 4% for over-43s.

PGT-A (Preimplantation Genetic Testing for Aneuploidy)

PGT-A screens embryos for chromosome abnormalities before transfer. The HFEA rates it RED for improving birth rates. No RCT evidence of benefit for most patients.

Single Embryo Transfer (SET)

SET means transferring one embryo instead of two or three. UK multiple birth rates dropped from 28% to 5% with no loss in success rates (HFEA, 2021).

Surrogacy

Surrogacy is when someone carries a pregnancy for intended parents. Legal in 4 European countries, banned in most others. Italy criminalized it worldwide in 2024.

This information is for general guidance. It is not medical advice. Always consult a fertility specialist for decisions about your treatment.