What is IVF, and what are the realistic chances?
In vitro fertilisation — eggs are collected, fertilised in a laboratory, and an embryo transferred to the uterus. It works, it works less often than most people assume, and success depends overwhelmingly on one factor: age.
The process:
Ovarian stimulation with injected hormones over roughly two weeks, to mature multiple eggs rather than the usual one, with monitoring by scan and blood test.
Egg collection under sedation, using a needle guided by ultrasound.
Fertilisation in the laboratory, either by mixing eggs and sperm or by injecting a single sperm directly into an egg — ICSI, used mainly for male factor infertility.
Embryo culture for several days, with the embryologist selecting which to transfer.
Transfer, usually of a single embryo, which is a deliberate policy because multiple pregnancy carries substantially higher risk to mother and babies.
Freezing of remaining viable embryos for later cycles.
Then a wait of around two weeks before a pregnancy test.
The success rates, plainly. Published figures vary by clinic and country, and the pattern is consistent: birth rates per embryo transferred are highest under 35 and decline substantially through the late thirties, becoming low by the early forties using a woman's own eggs. Donor eggs largely remove the age effect, because success tracks the age of the egg rather than the recipient.
How to read clinic statistics critically. Look for live birth rate per cycle started rather than per transfer, since the latter excludes cycles that were cancelled; check whether figures are age-banded; and be cautious of clinics reporting selectively.
What is frequently underestimated: the physical demands of stimulation; the emotional toll, which is substantial and is the reason counselling is offered and worth taking; the cumulative cost across multiple cycles; and add-on treatments, many of which are sold at extra cost with limited or no evidence of benefit — regulators in some countries publish ratings on exactly this.
Several cycles are commonly needed, and cumulative success across cycles is a more useful figure than any single attempt.
General information, not medical advice.