Getting Pregnant After 35: What You Need to Know When Trying for a Baby

A friend announces her second pregnancy at 38. A colleague mentions egg freezing over lunch, very casually, in a way that suggests she has thought about it rather a lot. You go home and do the thing we all do now, which is type your own age into a search bar at eleven at night and then wish you hadn't.

The internet is unkind about this subject. It talks about "geriatric pregnancy", a phrase I would happily see abolished, and it leads with cliff-edge graphs.

So let me start somewhere more useful. Lots of women in London and across the UK are having a first baby, or another one, in their late thirties and beyond, and many conceive naturally.

Fertility does change with age. But the change is gradual, your 35th birthday is not a gate closing, and there is more in your hands than the scary graphs suggest.

Before you read on, one question: what's actually worrying you most? 

Is it the time it's taking, something specific in your medical history, or the general sense that you've left it late? Those three worries have quite different answers, and knowing which one is yours will make the rest of this far more useful.

What actually changes with age?

You're born with every egg you'll ever have. The number falls over the years, and egg quality tends to shift too, which affects how readily an egg is fertilised and goes to develop. Most women notice the effects from the mid to late thirties.

Here is what that looks like in real numbers, from a prospective study that followed 782 couples across seven European centres, tracking intercourse and ovulation properly rather than relying on recall.

The proportion of couples who had not conceived after a year of trying:

•     8% of women aged 19 to 26

•     13 to 14% of women aged 27 to 34

•     18% of women aged 35 to 39

Read that again, because the framing matters enormously. At 35 to 39, more than four in five couples had conceived within the year.

And now the statistic almost nobody quotes, which I think is the most important one in this entire article. Of the couples who had not conceived after twelve cycles, between 43% and 63% went on to conceive during one further year of trying.

That is the real picture. Not a cliff. A slope, with a long runway after it.

The fertile window doesn't shrink

A small practical point from the same research group that I find genuinely cheering.

Nearly all pregnancies occur within a six-day fertile window, and that window does not get shorter with age. What changes is the per-day chance of conception within it. Women aged 19 to 26 had roughly twice the per-day probability of women aged 35 to 39.

So the target stays the same size. You just want to make sure you're actually aiming at it. Regular sex every two to three days across the month covers it without anyone having to stare at an app and feel like they're filing a tax return.

It takes two, and this part gets skipped

Fertility is not a women's problem that men occasionally contribute to. In that same study of 782 couples, where the male partner was aged 35 to 40, the proportion not conceiving within twelve cycles rose to between 18% and 28%.

On miscarriage, a systematic review and meta-analysis of paternal age found the pooled risk becomes clearly raised from age 40, and more so from 45. Being straight with you: at 35 to 39 the association was not statistically significant. So this isn't a reason for a 37-year-old man to panic. It is a reason for both partners to be in the room from the start.

The research on male preconception diet is still young. A 2024 scoping review of 37 studies found more fish and less sugary drinks, processed meat and total fat may improve fecundability, while stating plainly that specific dietary recommendations are precluded by the lack of clinical pregnancy outcomes and the shortage of randomised trials. In other words, the direction is sensible and the detail isn't settled. Anyone selling your partner a precise protocol is ahead of the evidence.

What can you actually do?

Plenty of everyday habits support your reproductive health. Only some have been shown to affect your chances of conceiving, and nothing here can promise a pregnancy. The aim is to get your body ready, not to fix something broken.

Folate. 400 micrograms daily, starting before you conceive, ideally about three months ahead, and continuing to week 12. Some women need 5mg, including those with a personal or family history of neural tube defects, a previously affected pregnancy, diabetes, or certain medications. Your GP will confirm which applies to you. Supplementation has also been associated with slightly better chances of conceiving in observational research, with a stronger signal in women with irregular or long cycles.

Then there's the question I get asked about more than almost any other, which is folic acid versus methylfolate. The honest answer has more nuance in it than either camp tends to admit, so here it is in full.

Folic acid is the synthetic form. Your body has to convert it, using an enzyme called MTHFR, into 5-MTHF, the active form that actually circulates and does the work. Methylfolate supplements skip that step and hand you the active form directly.

Roughly one in ten people of European ancestry carries two copies of a common MTHFR variant that reduces that enzyme's activity. You will find a great deal of content online claiming this means folic acid simply doesn't work for those people. That overstates it. The CDC's position is that people with MTHFR variants can process all forms of folate including folic acid, and that blood folate in this group runs around 16% lower at the same intake. A real difference, not a roadblock.

What the trials do show consistently is that methylfolate raises blood folate at least as well as folic acid, and leaves considerably less unmetabolised folic acid circulating. Whether that second part matters clinically is genuinely unknown, and I would be overselling it if I told you otherwise. I lean towards methylfolate in practice for those reasons, and because it is one less conversion step to think about. Calcium-L-methylfolate is a permitted supplement form in the UK, so it is straightforward to buy.

Here is the part I won't bend on. Every trial that established folate prevents neural tube defects used folic acid. No trial has shown that methylfolate prevents them. That is not a minor gap, and it sits precisely where getting it wrong cannot be undone.

So my advice is additive rather than substitutive. Take the 400 micrograms of folic acid the NHS recommends, from before conception through to week 12, and add methylfolate alongside it if you prefer having the active form. Please don't swap one for the other during that particular window. If you're in one of the higher-risk groups above, that goes double, and it's a conversation for your GP rather than for a blog post.

Worth knowing either way:from 13 December 2026, non-wholemeal wheat flour in the UK has to be fortified with folic acid at 0.25mg per 100g. So if you eat ordinary bread, some is arriving whether you planned it or not.

Food. Vegetables, wholegrains, pulses, fish and healthy fats. No strict plan required. The best review of diet and fertility, from the leading research group in this area, found that healthy overall dietary patterns are associated with better fertility in women and better semen quality in men, that folic acid looks genuinely useful, and that vitamin D does little in the absence of deficiency. The same review reported that antioxidant supplements do not benefit women undergoing fertility treatment, though they may help when given to the male partner. I mention that last point because antioxidants are among the most heavily sold supplements in this space, often to the wrong person.

Weight and movement. Being significantly over or under weight can affect ovulation, and regular activity helps. The evidence for higher BMI affecting time to pregnancy is reasonably consistent. For low BMI it's genuinely mixed, so please don't read this as a reason to diet. In fact, eating too little for your activity level is one of the more common problems I see in women trying to conceive, and it works against you.

Smoking. Stopping is one of the most useful things either of you can do, for many reasons beyond fertility.

Alcohol. UK advice is to avoid alcohol while trying for a baby, and that's what I'd suggest. I'll be honest about why: it's a precautionary position rather than a dramatic fertility finding. A large Danish cohort of 6,120 women found no discernible effect on fertility below 14 drinks a week. I tell clients this because I'd rather they trusted me than discovered later that I'd overstated something. The precaution still makes sense, because nobody knows the exact moment conception happens.

Caffeine. This one deserves more than a line, because the research and what I see in clinic don't quite agree, and I'd rather show you both than pick the convenient one.

Start with the evidence. A dose-response meta-analysis found little if any association between coffee or caffeine and the chance of conceiving. There's a separate signal for miscarriage risk at higher intakes, which belongs to pregnancy rather than conception. So at population level, coffee does not appear to be standing between you and a baby.

But population averages hide individual people, and the pattern I see most often is a specific one: someone in a demanding job, running on caffeine, sleeping badly, wondering why nothing is shifting.

Here's the chain, and every link in it is evidenced, even though nobody has tested the whole chain as one thing.

Caffeine raises cortisol, and tolerance is only partial. A study measuring cortisol across the waking day concluded that cortisol responses to caffeine are reduced, but not eliminated, in people who drink it daily. If your stress load is already high, caffeine is adding to it rather than sitting neutrally alongside it.

People clear caffeine at very different rates. Most of it is broken down by an enzyme called CYP1A2, and a common genetic variant makes some people slow metabolisers. In one large study, around 55% of participants carried the slow version, and higher coffee intake was linked to raised cardiovascular risk only in that group. Which means "coffee is fine" can be perfectly true for your colleague and not true for you.

Caffeine disrupts sleep later into the day than most people realise. A meta-analysis of 24 studies found it cut total sleep time by around 45 minutes and sleep efficiency by 7%. The authors worked out practical cut-offs, and this is the detail that tends to make clients sit up: for a 10pm bedtime, a standard coffee needs to be drunk by about 1pm.

And poor sleep affects metabolism. A randomised crossover study found that experimental sleep restriction impaired insulin signalling in human fat cells. Insulin regulation matters for ovulation, and metabolic health is associated with semen quality.

So, the honest position. There's no good evidence that caffeine itself lowers your chance of conceiving. There is reasonable evidence that in some people it raises cortisol, damages sleep and nudges metabolism the wrong way, and all three of those matter when you're trying for a baby.

Which makes the useful question not "is coffee bad?" but "what is coffee doing to me specifically?" If your sleep is poor, if you feel wired rather than alert, if you need it to function rather than enjoy it, that's worth looking at rather than defending.

I'll be straight about my own bias. I don't clear cortisol efficiently, and taking coffee out made a real difference to me. That's one person's experience rather than evidence, and I mention it so you know where my interest in this comes from.

With clients I'd suggest a trial rather than a rule. Take it out properly for the stretch we're working on your fertility, watch what your sleep and energy do, and decide from there. If nothing changes, have your coffee back with my blessing.

Sleep and stress. Here I'm going to disappoint the internet. The evidence that stress directly reduces your chance of conceiving is weak. The best study found a borderline result on one stress marker and nothing on cortisol, and it couldn't untangle the obvious problem that struggling to conceive is itself extremely stressful. What stress plausibly does affect is how you feel, how you sleep and how often you have sex, which matters. So look after yourself because you deserve it, not because someone told you that relaxing will get you pregnant. That particular line does real harm.

Medicines and supplements. Mention them to your GP or pharmacist, and never stop prescribed medication without advice.

Existing conditions. Thyroid problems, diabetes and similar are worth reviewing before you conceive. Thyroid in particular is easy to overlook and genuinely relevant.

Your cycle. If you know roughly when you ovulate, you can make sure you're covering the fertile window.

When should you seek advice?

The NHS advises couples to see their GP if they haven't conceived after a year of trying. At 36 or over, it suggests getting advice sooner rather than waiting out that full year.

So if something is nagging at you, book the appointment instead of counting months. I say this to clients constantly: a GP appointment costs you nothing and buys you information. Waiting costs you time, which is the one thing we can't get more of.

Ask to be seen earlier if you have:

•     irregular or absent periods

•     a history of fertility problems

•     endometriosis or PCOS

•     previous pelvic surgery

•     previous cancer treatment

•     suspected tubal problems

•     any concerns about male fertility

Your GP can arrange initial blood tests and explain what they mean. For independent information on assessment and treatment, the HFEA and NICE fertility guidance are both good places to start.

Where nutrition and lifestyle fit in

Preparing for pregnancy takes more than timing sex correctly. What you eat, how your metabolism and thyroid are doing, your digestion and how well you absorb nutrients, your daily habits and how well you recover all feed into your reproductive wellbeing.

Personalised preconception support is useful if you're not sure where to begin, or if you've been told everything is "normal" and you don't feel it. It runs alongside medical care and doesn't replace it. It can't reverse age-related changes or guarantee conception, and if you need a fertility assessment or treatment, that comes first.

What it can do is make sure that when the moment comes, your body is as well prepared as it can be. Which is not nothing. It's quite a lot, actually.

Frequently asked questions

Is it possible to get pregnant naturally after 35?

Yes. Plenty of women conceive naturally in their late thirties and beyond. It can take longer than in your twenties, but age alone doesn't rule it out, and more than four in five couples in that age group conceive within a year.

How long should I try before seeking help?

NHS guidance says women aged 36 and over should seek advice sooner than the usual year. If you're 35 with irregular cycles or a known condition, speak to your GP early too.

Does fertility decline significantly after 35?

Gradually, not suddenly. The change shows more from the mid to late thirties. Averages only tell you so much, and your own pattern may look nothing like the average.

Can lifestyle changes support fertility after 35?

They support your general reproductive health, which is worth doing in itself. Not smoking, eating well, sleeping properly and getting enough rather than too little food all help your body prepare. They won't reverse age-related change or guarantee conception, so use them alongside medical advice rather than instead of it.

What should I do before trying for a baby after 35?

Start folic acid, check any medication with your GP, stop smoking, avoid alcohol, make sure cervical screening is up to date, and have a preconception chat with your GP. That's also a good moment to ask about an assessment if you're worried.

Does my partner need to do anything?

Yes, and ideally at the same time as you. Sperm takes around three months to form and mature, so changes made now show up in roughly a season.

Preparing with support

Natural Fertility offers personalised nutritional and lifestyle support to women, men and couples preparing to conceive, whether naturally or with assisted conception.

If you'd like fertility support that fits your actual situation, rather than a plan designed for someone else, book a discovery call and we'll talk through what that might look like.

References

1.     Dunson, D.B., Baird, D.D., Colombo, B. (2004). Increased infertility with age in men and women. Obstetrics and Gynecology, 103(1), 51–56. doi.org/10.1097/01.AOG.0000100153.24061.45

2.     Dunson, D.B., Colombo, B., Baird, D.D. (2002). Changes with age in the level and duration of fertility in the menstrual cycle. Human Reproduction, 17(5), 1399–1403. doi.org/10.1093/humrep/17.5.1399

3.     Gaskins, A.J., Chavarro, J.E. (2018). Diet and fertility: a review. American Journal of Obstetrics and Gynecology, 218(4), 379–389. pmc.ncbi.nlm.nih.gov/articles/PMC5826784/

4.     du Fossé, N.A., van der Hoorn, M.-L.P., van Lith, J.M.M., le Cessie, S., Lashley, E.E.L.O. (2020). Advanced paternal age is associated with an increased risk of spontaneous miscarriage: a systematic review and meta-analysis. Human Reproduction Update, 26(5), 650–669. doi.org/10.1093/humupd/dmaa010

5.     Mikkelsen, E.M., Riis, A.H., Wise, L.A., et al. (2016). Alcohol consumption and fecundability: prospective Danish cohort study. BMJ, 354, i4262. doi.org/10.1136/bmj.i4262

6.     Lyngsø, J., Ramlau-Hansen, C.H., Bay, B., et al. (2017). Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis. Clinical Epidemiology, 9, 699–719. doi.org/10.2147/CLEP.S146496

7.     Lovallo, W.R., Whitsett, T.L., al'Absi, M., Sung, B.H., Vincent, A.S., Wilson, M.F. (2005). Caffeine stimulation of cortisol secretion across the waking hours in relation to caffeine intake levels. Psychosomatic Medicine, 67(5), 734–739. doi.org/10.1097/01.psy.0000181270.20036.06

8.     Cornelis, M.C., El-Sohemy, A., Kabagambe, E.K., Campos, H. (2006). Coffee, CYP1A2 genotype, and risk of myocardial infarction. JAMA, 295(10), 1135–1141. jamanetwork.com/journals/jama/fullarticle/202502

9.     Gardiner, C., Weakley, J., Burke, L.M., et al. (2023). The effect of caffeine on subsequent sleep: a systematic review and meta-analysis. Sleep Medicine Reviews, 69, 101764. sciencedirect.com/science/article/pii/S1087079223000205

10.  Broussard, J.L., Ehrmann, D.A., Van Cauter, E., Tasali, E., Brady, M.J. (2012). Impaired insulin signaling in human adipocytes after experimental sleep restriction: a randomized, crossover study. Annals of Internal Medicine, 157(8), 549–557. acpjournals.org/doi/10.7326/0003-4819-157-8-201210160-00005

11.  Samaniego-Vaesken, M.L., Morais-Moreno, C., Carretero-Krug, A., et al. (2024). Supplementation with Folic Acid or 5-Methyltetrahydrofolate and Prevention of Neural Tube Defects: An Evidence-Based Narrative Review. Nutrients, 16(18), 3154. doi.org/10.3390/nu16183154

12.  Centers for Disease Control and Prevention. MTHFR Gene Variant and Folic Acid Facts. cdc.gov/folic-acid/data-research/mthfr/index.html

13.  Cochrane, K.M., Elango, R., Devlin, A.M., Mayer, C., Hutcheon, J.A., Karakochuk, C.D. (2024). Supplementation with (6S)-5-methyltetrahydrofolic acid appears as effective as folic acid in maintaining maternal folate status while reducing unmetabolised folic acid in maternal plasma: a randomised trial of pregnant women in Canada. British Journal of Nutrition, 131(1), 92–102. doi.org/10.1017/S0007114523001733

14.  Pietrzik, K., Bailey, L., Shane, B. (2010). Folic acid and L-5-methyltetrahydrofolate: comparison of clinical pharmacokinetics and pharmacodynamics. Clinical Pharmacokinetics, 49(8), 535–548. doi.org/10.2165/11532990-000000000-00000

15.  Colson, N.J., Naug, H.L., Nikbakht, E., Zhang, P., McCormack, J. (2017). The impact of MTHFR 677 C/T genotypes on folate status markers: a meta-analysis of folic acid intervention studies. European Journal of Nutrition, 56, 247–260. doi.org/10.1007/s00394-015-1076-x

16.  UK Flour Millers. Folic acid: Bread and Flour Regulations. ukflourmillers.org/knowledge-hub/standards-regulations/bread-flour-regulations/folic-acid

17.  NHS. Infertility. nhs.uk/conditions/infertility/

18.  NHS. Vitamins, supplements and nutrition in pregnancy. nhs.uk/pregnancy/keeping-well/vitamins-supplements-and-nutrition/

19.  NICE. Fertility problems: assessment and treatment (CG156). nice.org.uk/guidance/cg156

20.  HFEA. Human Fertilisation and Embryology Authority. hfea.gov.uk