IVF success rates: what the numbers really mean

When you start looking into IVF, you'll see success rates everywhere — on clinic websites, in articles, from doctors. They range from 30% to 70%, sometimes higher. Understanding what these figures actually mean is essential before you can use them to make decisions.

The most important distinction: pregnancy rate vs live birth rate. Pregnancy rate counts positive pregnancy tests, including pregnancies that end in early miscarriage. Live birth rate counts babies born. The difference can be 10 to 15 percentage points. Always ask for live birth rates — that's the number that represents your real outcome.

IVF success rates by age: the real data

Data from the French Agence de la biomédecine and the Spanish SEF (Sociedad Española de Fertilidad) paint a consistent picture. For IVF with own eggs: live birth rate per transfer is approximately 33% for women under 35, 27% between 35 and 39, and 15% after 40. At 43, the rate drops to around 5% per cycle. For IVF with donor eggs: the live birth rate rises to approximately 50-57% per transfer, largely independent of the recipient's age — because it's the donor's eggs (typically from a woman aged 18-35) that determine chromosomal quality. After 3 complete cycles with own eggs: cumulative live birth rates are approximately 60-70% under 35, 45-55% between 35-37, and 30-40% between 38-40.

What actually influences your personal chances

Age is the most significant factor — specifically, the age of the eggs. Ovarian reserve (AMH, antral follicle count): affects the number of eggs retrieved, not their quality directly. Embryo quality: determined in the laboratory — this is where the embryology team makes a real difference. Clinic expertise: particularly on complex profiles (poor responders, recurrent implantation failure). Protocol optimisation: the right stimulation protocol for your specific profile. And PGT-A (genetic embryo testing): in women over 37-38, transferring only chromosomally normal embryos significantly improves per-transfer success rates and reduces miscarriage risk.

At WoMA, we believe you deserve to understand your numbers — not just hear them. We help you interpret your fertility workup results and choose the clinic in Spain best matched to your specific profile and prognosis.

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