Trying to Conceive After 35 — What Actually Changes
Age changes the odds, not the rules. What genuinely shifts after 35, what stays exactly the same, when to seek help sooner — and what a scan usefully adds.
Starting a family in your mid-to-late thirties is now completely ordinary, and most people who try at this age will conceive. Fertility does decline with age — that part is real — but the cliff-edge framing is not. The decline is gradual, it steepens through the late thirties, and it plays out as longer average time to conceive, not a switch that flips at a birthday.
The practical differences are two: it may take longer, and the timetable for asking for help moves forward. Everything else about how conception works is unchanged.
What actually changes after 35
Egg number falls. You are born with your full supply, it declines throughout life, and the fall runs faster through the late thirties. Fewer eggs mainly means fewer chances per year and a stronger case for not letting months drift.
Egg quality shifts. Chromosomal errors become more common with age, which is the main reason both time-to-conception and miscarriage rates rise. This is a change in odds across many cycles — it says nothing certain about any single egg or any single month.
Cycles can shorten. As reserve falls, some people notice cycles quietly getting a couple of days shorter. It is worth mentioning to your GP rather than dismissing.
Conditions have had longer to develop. Fibroids and endometriosis become more common with age, and both can affect fertility depending on where they sit. These are exactly the things a pelvic scan sees well.
What stays exactly the same
The mechanics. The fertile window is still the five days before ovulation plus the day itself, and ovulation still sits about 14 days before the next period. Timing matters as much as ever — our guide to follicle size by cycle day shows what a normal cycle is doing underneath.
Half the picture is still your partner. Sperm factors contribute in roughly a third of couples and change with age too. Assessment is for both of you from the start — semen analysis is arranged through your GP or a fertility clinic, and it is not something we offer at IUS London.
The basics still count. Folic acid before conception, not smoking, keeping alcohol low and weight in a healthy range all still move the odds in your favour, at any age.
When to seek help
| Your situation | When to see your GP |
|---|---|
| 36 or over | After 6 months of regular unprotected sex without conceiving — the standard advice moves forward with age. |
| Under 36, no known problems | After 12 months of trying. |
| Any age with irregular or absent periods, known PCOS, endometriosis or fibroids, previous pelvic surgery or infection, or known issues on either side | Straight away — do not wait the months out. |
One more reason not to drift: access to NHS-funded fertility treatment depends on age and varies by area, and referrals run through your GP. Starting the conversation at six months costs nothing; starting it at eighteen can cost options.
Ovarian reserve — what the tests do and do not say
Two markers describe ovarian reserve. The antral follicle count (AFC) is an ultrasound measurement: the small resting follicles in both ovaries, counted early in the cycle. AMH is a blood test your GP or fertility clinic can arrange. Together they estimate how many eggs remain and how the ovaries would respond to IVF stimulation.
Here is the honest part: reserve markers measure quantity, not quality, and they do not predict your chance of conceiving naturally this month. A lower count with regular ovulation can still conceive without help; a generous count guarantees nothing. Where the numbers earn their keep is planning — how urgently to act, and what treatment would realistically offer — which is exactly the decision the late thirties often turns on. Our guide to ultrasound for ovarian reserve goes deeper.
What we can measure for you
- 1
Antral follicle countA transvaginal scan early in your cycle, counting the resting follicles in both ovaries — the ultrasound half of a reserve assessment, in a 30-minute appointment.
- 2
Baseline pelvic checkThe same visit looks at the womb, lining and ovaries for fibroids, polyps and cysts — the structural questions that become more relevant with age.
- 3
Follicular tracking if neededIf whether-and-when you ovulate is the open question, two to four scans across one cycle answer it directly.
- 4
ResultsFindings explained on screen as we scan, written report usually within two hours — ready for your GP or fertility clinic to act on.
Your questions answered
Is 35 a fertility cliff edge?
How long should I try before getting help at 36 or over?
What is a good antral follicle count for my age?
Does a low AFC or AMH mean I cannot conceive naturally?
Should my partner be tested as well?
Is miscarriage more common after 35?
Where to go from here
What normal follicle growth looks like, day by day, with the numbers.
Read the guide →
CausesWhy Am I Not Getting Pregnant?Where the causes sit, and what a scan can and cannot tell you.
Read the guide →
ReserveUltrasound for Ovarian ReserveHow the antral follicle count works and what it tells you.
Read the guide →
A baseline you can plan around
An antral follicle count with a full pelvic assessment in one visit — counted properly, explained on screen at the appointment, and the written report usually with you within two hours, ready for your fertility clinic.
Kensington, London W8 4ED
3 mins from Notting Hill Gate
This article is general information about age and fertility, not individual medical advice. Assessment belongs with both partners and starts with your GP — NHS guidance on fertility problems sets out the pathway, including the tests ultrasound cannot replace. Access to NHS-funded treatment varies by age and area; your GP can tell you what applies where you live.
Written and clinically reviewed by the HCPC-registered sonographers who perform this scan at IUS London — a CQC-registered diagnostic ultrasound clinic (Provider ID 1-2775844974). Your own findings are explained to you at the scan and set out in your report.
Author: Yianni Kiromitis, Senior Sonographer, HCPC RA38415 — over 20 years’ experience in NHS and private ultrasound
Medically reviewed: 9 August 2026
