Many women these days are leaving it later than ever to have children. In the past, couples typically started families in their early twenties, whereas now many wait until their thirties or forties to get pregnant.

Women over 35 are slightly more at risk of complications, but the vast majority can expect an uncomplicated pregnancy and a healthy baby.  The most common problem faced by women in this age group can be getting pregnant in the first place, as fertility decreases with age.

When are women most fertile?

A woman is at her peak fertility somewhere between about 18 and 24. After the age of 35 a woman’s fertility starts to decrease quite rapidly.

About 94% of women aged 35 will conceive after trying for three years. Only 77% of 38 year olds will do so.

What factors can affect fertility as we get older?

Egg quantity and egg quality are the main age-related issues affecting a woman’s fertility. Women are actually born with all their eggs - up to two million. By the time a woman hits puberty this number has dropped to between 300,000 and 400,000.

During each menstrual cycle only one or two of the 20 or so eggs prepared will go on to become mature eggs. These are known as ‘good’ eggs, fit to be fertilised and then develop into a healthy pregnancy. As a woman ages, the number of ‘good’ eggs she has will naturally reduce.

As women get older, they are also more prone to irregular or shorter periods, which can make it more difficult to get pregnant.

The lining of the womb can become thinner too, making it harder for a fertilised egg to embed itself and stay put.

If you are finding it difficult to conceive, it is a good idea to seek advice from your doctor sooner if you are over 35, so that any problems can be spotted in good time.

What are the risks for mother and baby if you are over 35?

The good news is that you are not much more likely to have major complications than younger women.

The likelihood of getting gestational diabetes increases with age, but your doctor can advise you on diet to help prevent serious problems.

Women over 35 are at greater risk of having a baby with Down’s syndrome. The chances rise from 1 in 2000 for a woman in her twenties to 1 in 100 for a woman of 40.

Older mums have a slightly higher risk of miscarriage and stillbirth, but do remember that stillbirths are still extremely rare.

Older women are more at risk of high blood pressure, which can lead to pre-eclampsia, but you will be monitored throughout your pregnancy to prevent any further risk.

Babies born to mums over 35 are slightly more prone to premature birth or low birth weight.

The rates of induction, caesarean and assisted births (forceps or ventouse) are also slightly higher for older women.