Your age and fertility

These days, many women choose to put off having children until later in life (NHS 2009), when they’re more established in their relationships and careers. But how long can you wait, and are there downsides to starting your family at an older age? We’ve rounded up the research to bring you all the info you need.

How does my age affect my fertility?

How old you are does make a difference to your chances of getting pregnant, but perhaps not as much as you might think. Female fertility declines gradually, and remains high throughout your 30s (NICE 2018).

Among couples who are actively trying for a baby (having unprotected sex at least twice a week), the percentage of women who become pregnant within a year, based on their age, is:


Here are the exact figures:

• 19 to 26: 92 per cent
• 27 to 29: 87 per cent
• 30 to 34: 86 per cent
• 35 to 39: 82 per cent
  (NICE 2017)

We don't yet have accurate data for women 40 and over who are trying to conceive. However, among couples who aren't necessarily trying, but aren't using protection either, the percentage of women who become pregnant within a year is approximately:

• 20 to 24: 47 per cent
• 25 to 29: 45 per cent
• 30 to 34: 41 per cent
• 35 to 39: 34 per cent
• 40 to 44: 20 per cent
• over 45: 4 per cent
  (NICE 2017)

In general, among couples who don’t conceive within the first year of trying, about half will conceive during the second year (NICE 2017). So even if you’re in your late 30s, you have an excellent chance of getting pregnant within a few years.

Because most couples do conceive naturally given time, it's usually recommended that you only seek help from your GP if you haven't conceived after a year of having regular sex (two to three times a week) (NCCWCH 2013).

However, if you’re over 35, and you haven’t had a positive pregnancy test after a few months of trying, see your GP sooner rather than later (NCCWCH 2013). She can check if there are any problems and suggest treatments that may help.

If there is an issue with your fertility that can be helped with assisted conception treatments, it’s better to have these as soon as possible. This is because the success rates of in-vitro fertilisation (IVF) decrease as you get older. On average, the percentage of IVF treatments that are successful is:

• 29 per cent for women under 35
• 23 per cent for women aged 35 to 37
• 15 per cent for women aged 38 to 39
• nine per cent for women aged 40 to 42
• three per cent for women aged 43 to 44
• two per cent for women aged over 44
  (NHS 2018)

Remember that your age is just one of many factors that can affect your chances of getting pregnant. Your general and sexual health, your partner’s age, and how often you have sex also play important roles (NHS 2017, NICE 2017).

There are also several lifestyle factors that affect your fertility, including your body mass index (BMI), your diet, and whether or not you smoke (NHS 2017). So whatever your age, there’s plenty that you can do to boost your chances of conceiving.

I’m over 35. Does my risk of pregnancy complications increase?

Although your chances of conceiving are still good in your late 30s, the risk of pregnancy complications does unfortunately increase with age. This doesn’t mean that you’ll definitely have a complicated pregnancy; just that the risk is higher than if you had conceived at a younger age (NHS 2009).

Complications that are more common in older mums-to-be include:

• health problems, such as high blood pressure and pre-eclampsia
• complications during labour and birth, such as a longer labour, assisted delivery or c-section
• having twins or triplets, which increases the risk of certain other complications
• having a baby with a congenital problem, such as Down’s syndrome
  (NHS 2009)

Sadly, miscarriage and stillbirth are also more common among older women (NHS 2009).

Try not to let these worries stop you from having a baby though. If you are at an increased risk of complications, you’ll be offered extra care to help you manage the risks and have a healthy pregnancy (NHS 2009).

What about men’s fertility. Does it decline with age too?

Yes. Although men can remain fertile for longer than women - into their 50s and beyond - male fertility also gradually declines with age (RCOG 2011, Utting and Bewley 2011). And when older men do conceive, age-related changes in sperm quality can increase the risk of miscarriage or health problems for the baby (Utting and Bewley 2011).

Learn more about how age affects male fertility.

Why does fertility decline so rapidly?

The two most common causes of female infertility are:

• ovulation problems
• damage to the fallopian tubes
  (CKS 2013)

Ovulation problems can happen as you get older because the number of eggs in your ovaries (ovarian reserve) decreases with age. The fewer good quality eggs you have left, the more difficult it may be to conceive a healthy pregnancy (Bewley et al 2009, RCOG 2011, Utting and Bewley 2011)

About one per cent of women stop ovulating before they reach the age of 40 (premature ovarian insufficiency) (Willacy 2018).

Damage to the fallopian tubes may be caused by previous surgery, infection or another condition such as endometriosis (CKS 2013). The older you are, the more likely it is that you could have had a condition that affects your fertility this way. For example, an untreated chlamydia infection can develop into pelvic inflammatory disease, blocking your fallopian tubes (NHS 2017) .

Other age-related conditions that can affect fertility include:

• Endometriosis, which can cause fallopian tubes to thicken with scar tissue. If you have endometriosis, it may become more extensive as you age. The damage to fallopian tubes can also make an ectopic pregnancy more likely (Utting and Bewley 2011).
• Fibroids are more common in women over 30 and may cause fertility problems for some women (Utting and Bewley 2011).

Bear in mind that being overweight can make it more difficult to become pregnant. Losing weight may also help you to conceive if you have problems with ovulation that are due to polycystic ovary syndrome (PCOS) (Legro R, et al. 2015).

Find out more about the causes of infertility and pregnancy after the age of 35.

Why is the chance of twins higher for older women?

On average, about one in every 65 pregnancies in the UK is a multiple pregnancy (twins, triplets or more) (NHS 2016). But your chances of having non-identical twins or more increase with age (Utting and Bewley 2011).

It's thought that your body produces more of the hormone that makes you ovulate (follicle stimulating hormone, or FSH) as you get older. This is probably because there are fewer healthy eggs left in your ovaries (Utting and Bewley 2011).

This over-production of FSH can mean that more than one follicle ripens and releases an egg at the time of ovulation. If more than one egg is fertilised, this leads to non-identical twins or triplets (Utting and Bewley 2011).

You may be delighted at the prospect of conceiving twins. For some women, having a multiple pregnancy brings them their dream family in one pregnancy. But it’s also worth bearing in mind that caring for twins is more demanding of your time, emotions and finances, than caring for one baby. You may also need extra care during a multiple pregnancy.

If you're expecting twins or more, learn what to expect from your pregnancy, birth and life with your babies.

What will help me get pregnant?

Age aside, there are some steps you can take to give yourself the best possible chance of conceiving and having a healthy pregnancy. Check out our articles on how to prepare your body for pregnancy, and what lifestyle changes can improve your chances of conception.

If you don't get pregnant right away, just try to relax and keep positive. Your GP may advise you to have regular, unprotected sex (about two or three times a week) for a year (NCCWCH 2013), before investigating further.

You can visit your GP sooner than this if you’re over 35, or you know of any reasons you may have trouble getting pregnant, such as irregular periods or a risk of exposure to a sexually transmitted infection (STI) (NHS 2017, NHS 2017a).

If you’re having difficulties conceiving naturally, assisted conception techniques or other fertility treatments may improve your chances of successs (NHS 2017).

Learn more about getting pregnant in your 20s, 30s or 40s, or get tips, advice and support in our friendly community of mums and mums-to-be.