Did you know that if you want three children, you should start trying by age 23?!
- Dr. Sandra Yene Amougui
- Jul 4
- 2 min read
It sounds dramatic — but it’s based on a solid scientific study (Habbema et al., Human Reproduction, 2015).By modeling natural fertility over time, researchers estimated how late you can start trying to have 1, 2, or 3 children, without needing IVF — and still have a 90% chance of success.
The result? The more children you want, the earlier you should start.
Fertility and age: what biology tells us
Female fertility peaks between ages 20 and 25, then gradually declines after 30, and more sharply after 35.By age 40, chances of conceiving naturally are under 10% per cycle, even for healthy women.
Assisted reproduction (IVF) cannot fully compensate for this age-related decline — it doesn’t reverse egg quality or quantity loss.
Time to Pregnancy (TTP) — how long does it actually take to conceive?
Even with no fertility issues and regular unprotected sex, pregnancy is not always instant.
Average time to conceive by age:
Woman’s age | Average time to conceive |
20–24 | 3–4 months |
25–29 | 4–5 months |
30–34 | 6–8 months |
35–39 | 10–12 months |
40+ | 12–18 months or longer |
Chances of getting pregnant:
Woman’s age | Pregnant within 6 months | Within 12 months |
25 | ~60% | >85% |
30 | ~55% | ~75–80% |
35 | ~45% | ~60–65% |
40 | ~30% | <40% |
Half of all young couples conceive within 3 months.
By 35, it often takes twice as long — and uncertainty increases.
How early should you start, depending on how many children you want?
The Dutch team led by Habbema et al. developed a model to estimate the latest age to start trying if you want to have 1, 2, or 3 children, with a high probability of success (≥90%) — and without IVF.
How did they calculate it?
They considered:
Natural fertility decline by age
The average Time to Pregnancy (TTP)
A realistic gap between births (18 months between delivery and the next attempt)
Miscarriage risks and secondary infertility
And the time it takes to try for each child
Results: recommended latest starting age (without IVF)
Desired family size | Start trying by age... |
1 child | 32 |
2 children | 27 |
3 children | 23 |
IVF could give you an extra 3–5 years, but with no guarantees.
Key takeaways
Fertility declines well before menopause
The number of children you want matters a lot
Time to conceive increases with age, even for healthy couples
IVF cannot reverse natural decline
A preconception fertility check-up (AMH, FSH, ovarian ultrasound) can clarify your timeline
Thinking about pregnancy — now or later?
Planning ahead means more freedom.Book a preconception consultation — whether you’re just curious, unsure, or already trying.Let’s talk honestly and help you make informed choices.
Kindly yours,
Dr. Sandra Yene Amougui
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