IVF SUCCESS RATES BY AGE: WHAT THE DATA SHOW
CONTENTS
When a couple or a woman starts thinking about IVF, they usually look straight away for a percentage. "What are my chances?" is the most natural and common question. The truth, however, is that no percentage has real value unless it is seen in the right context. And the most important context is age.
The official bodies that collect and audit IVF data, such as the HFEA in the United Kingdom and the CDC in the United States, are clear: a woman's age is one of the most important factors in success, particularly when her own eggs are used. This does not mean that the outcome is determined by age alone, but it does mean that any discussion of chances that ignores the age group is incomplete.
What the official data show
The HFEA reports that in 2022 the average pregnancy rates after IVF with embryo transfer were 42% for patients aged 18-34, 16% for patients aged 40-42 and 9% for patients aged 43-44 when their own eggs were used. Correspondingly, the provisional birth rates per embryo transfer were 35% at ages 18-34, 10% at 40-42 and 5% at 43-44.
These figures are indicative and are not a prediction for any individual woman. Nevertheless, they describe a consistent biological trend: after 35, and even more after 40, the chance of success falls noticeably. The CDC, for its part, stresses that success rates vary by age group and that the figures must be interpreted with caution, as the data are influenced by the profile of the cases and the particular features of each clinic.
Why rates fall with age
The explanation is not simply the passing of time. In practice, two key factors are affected. First, ovarian reserve gradually declines, so fewer eggs are often collected per cycle. At the same time, egg quality also changes, which increases the likelihood of chromosomal abnormalities, reduces implantation potential and increases the risk of miscarriage.
For this reason, after 40 a higher likelihood of miscarriage is seen, along with the need to assess the overall reproductive plan more carefully. Age on its own does not rule out a successful attempt, but it strongly affects how the results of each cycle are interpreted.
How to read the rates correctly
One of the most common mistakes is comparing different measures without distinguishing clearly between them. It is important to stress that the rate per embryo transfer is a separate figure, different from the rate per cycle or per egg retrieval. The CDC explains that different measures reflect different stages of treatment. The rate at which a cycle reaches egg retrieval is one thing, the rate at which a transfer takes place is another, and the rate of live births after all the transfers linked to one egg retrieval is yet another.
The second mistake is comparing clinics as if they treated uniform groups. A unit that takes on more complex cases or older women may show lower overall rates, without this reflecting a lower quality of medical care.
What changes when donor eggs are used
The rates that fall sharply with age mainly concern cases in which the woman's own eggs are used. In treatments with donor eggs, the decisive biological factor is the age of the egg, and the recipient's age does not play the same role. The CDC states that results in these cases are not broken down by age group as they are for cycles using the woman's own eggs, while the ASRM points out that egg donation can largely bypass the age-related decline in implantation and birth rates.
This does not mean that the recipient's age no longer matters. An older age means greater attention to obstetric risks and requires careful antenatal and medical assessment.
The key points
Rather than looking for a fixed success rate, it is more useful to consider what the realistic range of chances is, based on:
- age
- ovarian reserve
- history
- the proposed treatment plan
Age is not the only factor, but it is usually the starting point of the prognosis.
Important note
This article is for information only and does not replace an individual medical assessment. Decisions about further testing, the choice of treatment and the timeline should be made together with a specialist in reproductive medicine.
Useful sources
He supports scientific excellence in clinical practice and recognizes the possibilities offered by modern reproductive methods to couples who wish to have a child of their own.
His profileThe content of this article is for information only and does not replace a medical examination and advice.
