Around 7% of all babies born in the UK are born before 37 completed weeks of pregnancy. Tommy's the Baby Charity is committed to finding the causes. Charlotte Davies, who runs Tommy's pregnancy advice line, offers some advice on ways of minimising the risk and heartache of premature birth.
Among the 650,000 births per year in the UK, there are about 45,000 premature births – 125 babies born too soon each day.
Despite improvements in antenatal and neonatal care, the number has not significantly decreased since the 1960s.
Although the causes are not yet fully understood, research has identified some factors that may increase the risk of having a premature baby.
Multiple pregnancy The overstretching of the womb in the case of twin or triple pregnancies.
Fetal development If the baby is not thriving in the womb, for example if the blood supply from the placenta is impaired or there is evidence of growth retardation.
Lifestyle factors Some habits or lifestyle influences of the mother, including smoking, using recreational drugs, high caffeine intake, poor diet or underweight, and over-strenuous physical activity.
Previous gynaecological history Damage to the opening of the womb can result from surgery on the cervix. This can cause it to open too soon in pregnancy, resulting in premature labour.
Pregnancy-specific maternal disease Certain medical conditions specific to pregnancy can, if left untreated or on becoming more severe, cause pre-term labour. Examples include pregnancy-induced diabetes and pre-eclampsia (a cause of at least 15% of all pre-term births) and obstetric cholestasis (liver disease characterised by excessive itching).
Infection Vaginal infections, such as gonorrhoea, chlamydia, trichomonas, bacterial vaginosis and group B streptococci have all been linked to pre-term labour. Bladder infections can also trigger early labour if left untreated.
There are also circumstances where premature delivery is initiated by the medical staff. For example if a woman suffers from pre-eclampsia or the baby is not thriving in the womb and either the health of the mother or the baby is at risk, then premature delivery of the baby may be the only option.
While the experience of a premature birth may be very traumatic for all the family involved, there is seldom any adverse effect on the mother’s physical health. Once pre-term labour is suspected, most women will receive tocolytic drugs to attempt to stop contractions. These may stop labour altogether or may delay the onset long enough for steroids to be administered to the mother, which help the baby’s immature lungs develop before delivery. The drugs can also help to delay birth while the mother is transferred to a hospital with an available special care baby unit (SCBU) cot. For the mother, physical recovery from premature labour and delivery will be no different than from a later delivery although there can be greater emotional stress.
Although most premature babies have no disabilities or ongoing difficulties at all, it is true that the earlier they were born, the more likely it is that they may have a problem. The most common problems will be mild or moderate difficulties, perhaps a squint or problems with co-ordinating movement. In a small number of cases, the disability may be more severe. Current thinking suggests that the likelihood of a baby having a significant disability is about 10% if they were born at 28 weeks and 20-30% if they were born at around 24 weeks.
In a recent British study, results show that about half of babies born before 26 weeks had no problems, a further 25% had mild to moderate difficulties, such as hearing problems or short-sightedness, while the remaining quarter did have severe disabilities, such as cerebral palsy, developmental delay, hydrocephalus and blindness.
For women who have had one pre-term birth, the risk of the same thing happening in the next pregnancy is around one in six. But although the risk for a second premature birth is slightly higher than in the first pregnancy, it is not a necessary outcome. In fact, 85% of women who have given birth prematurely in their first pregnancy will have a normal pregnancy lasting more than 37 completed weeks the second time around.