Two separate things decline with age — how many eggs you have, and how many of them can make a normal embryo. Only one can be measured, and it is not the one that decides outcomes.
Fertility declines with age. Everybody knows that sentence, and almost nobody is told what it actually means — which parts change, how fast, and what the technologies people are counting on can and cannot do about it.
This is not an argument for having children earlier. It is the information needed to make the decision knowingly rather than by default.
What changes, and in what order
Two separate things decline, and confusing them causes most of the misunderstanding.
| Ovarian reserve (quantity) | Egg quality | |
|---|---|---|
| What it is | How many eggs remain | What proportion of them can make a chromosomally normal embryo |
| Can it be measured? | Yes — AMH, antral follicle count | No direct test. It is inferred from age. |
| What it predicts | How many eggs a stimulated cycle will yield | Whether those eggs make babies |
| Can it be improved? | No | No |
The clinically important point is that quality is the one that decides outcomes, and it is the one nobody can measure. A woman of 41 can have a reassuring AMH and still have a low chance per cycle, because her ovaries are producing a reasonable number of eggs of which fewer are chromosomally normal. A normal AMH at 41 is not a reprieve; it is a measure of quantity only.
The shape of the curve
Fertility is highest in the early twenties, declines gradually through the late twenties, more noticeably from the early thirties, and steeply from around 37. Miscarriage risk moves in the opposite direction over the same period, for the same underlying reason — a rising proportion of embryos with the wrong number of chromosomes.
The clearest evidence for this comes from IVF registry data. Cumulative live birth rates per egg retrieval reported by SART for 2023 fall from 53.2% under 35, to 39.9% at 35–37, 26.2% at 38–40, 13.2% at 41–42 and 4.1% above 42. That is a decline of more than tenfold across roughly a decade, in a treated population with laboratory assistance.
The donor-egg observation. When donor eggs from a young donor are used, success rates track the donor’s age rather than the recipient’s, and remain high well into the recipient’s forties. This is the cleanest demonstration that the limiting factor is the egg, not the uterus — and it is also why “my periods are still regular” tells you very little about your fertility.
Men are not exempt
Male fertility declines more gradually, but it does decline. Semen volume, motility and DNA integrity fall with age, time to conception lengthens, and advanced paternal age has been associated with a modest increase in certain conditions in offspring. A semen analysis is a reasonable part of planning for a couple where the man is in his forties, not only where there is a known problem.
What actually helps, and what does not
Things with a genuine effect
- Stopping smoking. Smoking is associated with earlier menopause and reduced IVF success. It is the single most modifiable factor.
- Weight in a healthy range. Both significant excess and significant deficiency disrupt ovulation.
- Treating what is treatable. Thyroid disorders, raised prolactin, PCOS, endometriosis, fibroids distorting the cavity — each has a treatment, and each is more usefully addressed at 32 than at 39.
- Knowing your numbers early. An AMH and antral follicle count in your early thirties will not tell you when you will conceive, but it will tell you whether your reserve is unusually low for your age — which is information you can act on.
Things that do not do what people hope
- Supplements. Nothing available over the counter restores egg quality. Folic acid before conception is important for the baby, not for the egg.
- Regular periods. Reassuring about ovulation, silent about egg quality.
- Feeling well and looking young. Ovarian ageing does not correlate with how you feel.
- IVF as an insurance policy. IVF works with the eggs you have. It does not make older eggs younger, and its success rate falls with age along the same curve.
Egg freezing: what it is and is not
Freezing eggs stores them at the quality they have on the day they are collected. That is genuinely useful — it is the one intervention that acts on the actual problem — but it comes with conditions that are often glossed over.
- It works better the earlier it is done. Eggs frozen at 31 are more useful than eggs frozen at 38. Freezing at 39 stores 39-year-old eggs.
- Numbers matter. Not every egg survives thawing, not every surviving egg fertilises, and not every embryo is normal. A meaningful chance of a live birth usually requires a substantial number of mature eggs, which may mean more than one collection cycle.
- It is not a guarantee. It improves the odds of a future option. It does not promise a baby.
- There is a real cost — the collection cycles, and then annual storage for as long as the eggs are held.
Used with clear expectations — by a woman in her early thirties who wants to keep an option open — egg freezing is a reasonable decision. Sold as insurance against any timeline, it is not.
When to get assessed rather than wait
- Under 35, trying for 12 months without conceiving
- 35 or over, trying for 6 months
- Over 40, or with irregular or absent periods — seek assessment straight away rather than waiting out an interval
- Known endometriosis, PCOS, previous pelvic surgery or pelvic infection, previous chemotherapy, or a family history of early menopause — earlier assessment regardless of how long you have been trying
- Two or more pregnancy losses — assessment now, not after a third
PC&PNDT notice. Prenatal sex determination is not done at this hospital and is prohibited by law under the Pre-conception and Pre-natal Diagnostic Techniques Act, 1994. All ultrasound examinations here are performed for medical indications only.
At Cosmic. A fertility assessment is a consultation, an ultrasound, an AMH with antral follicle count, thyroid and prolactin, and a semen analysis for the partner. It takes about one cycle and gives you facts instead of anxiety. Coming early costs a consultation. Coming late can cost the option itself.
Considering IVF, or unsure whether you need it?
Cosmic Women’s Hospital & IVF Center is a Level 2 ART clinic in Naroda, Ahmedabad, registered under the ART (Regulation) Act, 2021. Consultations are by appointment, and you will be given a written, itemised estimate before any treatment begins.
77-9383-9383
3rd Floor, The Capital Corporate, Nr. Naroda Muktidham, Naroda, Ahmedabad 382330 · Book an appointment
Sources
- Society for Assisted Reproductive Technology. National Summary Report, 2023 preliminary data. sartcorsonline.com
- Human Fertilisation and Embryology Authority. Fertility treatment: key facts and statistics, 2022 data. hfea.gov.uk
Related reading
Book a consultation
Tell us how we can help and we will call you back.
Cosmic Women's Hospital
Cosmic Women’s Hospital & IVF Center is a registered Level 2 ART clinic in Naroda, Ahmedabad — obstetrics, gynaecological surgery, IVF and ICSI, with ultrasound in-house and 24-hour emergency obstetric cover. Articles here are written by the clinical team and medically reviewed by Dr. Rahul Khatri or Dr. Bhargavi Khatri before publication.
