causes of Premature Births

Stress and depression in pregnancy is a major cause of premature birth, experts have warned. Research shows that stress hormones - which play a crucial role in the development of the unborn baby - shoot up in women who are depressed during pregnancy. High levels of these hormones are involved in triggering labour, leading scientists to believe they could be behind many of the 45,000 premature births that occur in the UK each year - with potentially devastating results. Premature babies - born before 37 weeks of pregnancy - are more likely to die in the first weeks of life and are at risk of a host of health problems, with one in ten developing a permanent disability such as lung disease, cerebral palsy, blindness or deafness. While many of these early births can be explained by medical reasons, such as infection or complications with the pregnancy, around 30 per cent are unexplained. Dr Veronica O'Keane, an expert in mental health in pregnancy, said "many thousands" of the unexplained premature births are likely to be caused by soaring levels of stress hormones - and they could be prevented by treating stress and depression in pregnancy.

However, despite depression being more common during pregnancy than after it, many people, including doctors, refuse to acknowledge that mothers-to-be are vulnerable to the condition. Calling for more research into the topic, Dr O'Keane, a psychiatrist at King's College London, said: "There is a myth, that doesn't have any scientific support, that depression doesn't happen during pregnancy, that women are happy during pregnancy. But that just isn't true. "Half of the population becomes pregnant and depression is an incredibly common problem. "Most people are parents but there is a complete dearth of literature in this area. I find this extraordinary, one of the great mysteries of society. "There isn't even any good literature on what happens, let alone what happens when things go wrong." It is thought that high levels of stress hormones such as cortisol in the womb may also affect the brain of the unborn child. Previous studies have shown that toddlers born to stressed mothers-to-be have double the risk of having lower than average IQs. The children are also more likely to be hyperactive, have emotional problems and not do as they are told.

Work carried out by Dr O'Keane, and presented at a London conference held by the Institute of Psychiatry, suggests that children whose mothers become depressed during pregnancy find it harder to handle stress themselves. Tests on two-month-old babies showed that those whose mothers were depressed before their birth produced higher levels of stress hormones when given routine childhood jabs against infection. It is thought that the hormones, including cortisol, play a key role in depression, meaning these children may be more prone to develop depression themselves in later life. "This abnormality in cortisol secretion would seem to be an inter-generational way of transmitting depression without it being genetic," said Dr O'Keane. Sophie Corlett, of the mental health charity Mind, said that the stigma associated with depression meant that many pregnant women are reluctant to ask for help. "When women are pregnant, they realise they are supposed to be full of excitement and they are bemused and slightly ashamed of not feeling that way, which can more difficult to seek support."