Recently I was interviewed on the potential health considerations for women and their babies if giving birth after the age of 30. Here is what was discussed.
In the past, an older mother often meant a woman who already had a large family and was having her fifth or sixth baby. Having many pregnancies often led to complications. Today an older mother usually means someone who has chosen to start her family later and is often fit and well nourished. It is still true that simply by being older, there is an increased chance of developing medical disorders such as diabetes, high blood pressure or other chronic diseases, which can affect pregnancy and birth.
Does the risk of birth defects increase?
The risk of giving birth to a child with a defect does increase as the mother's age increases, due to issues with chromosome division. The traditional age at which a woman is considered to be at higher risk for chromosomal abnormalities is 35. Approximately 1 in 1400 babies born from women in their 20s have Down's syndrome; this increases to about 1 in 100 babies born to women in their 40s.
Will the risk of miscarriage increase?
Most miscarriages occur in the first trimester for women of all ages. The risk of miscarriage increases with age. Studies suggest about 10% of recognised pregnancies for women in their 20s end in miscarriage. The risk rises to about 20% at ages 35 to 39, 35% at ages 40 to 44, and more than 50% by age 45. The age-related increase is caused, at least in part, by increases in chromosomal abnormalities.
What other issues can arise?
Chronic health problems, such as diabetes or high blood pressure, are more common in women in their 30s and 40s. High blood pressure and diabetes can also develop for the first time during pregnancy. Stillbirth is more common in women over 35. Older women are also more likely to have low-birth-weight babies (less than 5.5 pounds). Caesarean birth is also slightly more common for women having their first child after 35.
What about the birth itself?
There is a clear pattern of increased intervention with the increasing age of the mother. Above 35, the chances of an induced labour, an epidural, or forceps/ventouse delivery are increased. Virtually all studies agree that the rate of caesareans also rises with maternal age. Some research has found that foetal distress is more commonly diagnosed in older mothers, which partly explains why caesarean rates are higher. There is also some evidence that older mothers are more likely to have a longer second stage of labour because the muscles of the uterus do not work as well as women get older.
The good news
Despite the real or perceived risks, studies agree that the actual outcome for the baby is often every bit as good as that for younger mothers, and the absolute risks of serious problems are very low for all age groups. Birth statistics over recent decades show a huge swing in favour of delaying parenthood until the 30s and beyond. In 2006, 48% of births in England and Wales were to women aged over 30, compared to just 28% in 1986.