Reasons for a premature baby

Babies born early need special care and monitoring to help them to gain weight and mature fully outside the womb. Babies born before 37 weeks are defined as premature, whilst those born between 24 and 28 weeks are 'extremely premature'. Before week 24, babies are significantly less developed, although a small proportion do survive, at 23 weeks there is a 17 per cent chance, rising to 39 per cent at 24 weeks and 50% at 25 weeks.

Advances in neonatal care mean the outlook is improving all the time. According to UK charity 'Bliss', about 80 per cent of extremely low birth weight babies, those under 1kg (2.2lb), now survive; 20 years ago, it was about 20 per cent.

There isn't always a clear reason for premature birth, but possible causes include a previous premature birth, diabetes, smoking or poor nutrition in pregnancy, twin or multiple pregnancy, and cervical incompetence (when the cervix dilates and opens too early). This can be treated with a stitch placed around the cervix muscle at 12-14 weeks to keep it closed, which is removed at week 36 or cut in the event of early labour.

The most common cause of premature labour, though, is premature rupture of the membranes (PROM). The trigger is often unknown, but possible factors include vaginal infection, excessive amniotic fluid, or carrying twins or multiples. If you think your membranes have ruptured, consult your doctor or midwife immediately. You may go into labour, be given antibiotics to prevent infection or delay birth, or be induced if there is infection or danger to the baby. Before labour, you may be given drugs to help the baby's lungs to mature more quickly.

Other complications that may necessitate an induced early delivery include diabetes, intrauterine growth restriction (IUGR), placenta praevia and pre-eclampsia. If the situation is putting you or your baby at risk, he or she may be delivered by caesarean section.