One pregnant woman in every 200 develops a liver disease, called obstetric cholestasis.(1) This can cause serious problems for the unborn baby, including premature birth and fetal distress. Tragically, some babies are stillborn. Much uncertainty surrounds why this disease can put babies at risk, and how best to protect them. Researchers are searching for answers, by investigating possible effects on babies' hearts.

Severe stress during pregnancy can almost double the risk of having a stillbirth, say researchers.
A Danish study of 19,000 women during the last three months of pregnancy found that a third scored highly for stress.

Of the women in this group, 29 - or 0.5% - had stillbirths after 28 weeks.
In both the intermediate and low stress groups, the stillbirth rate was around 0.3%.

Although the figures are small, the researchers say the difference is significant.

Dr Kirsten Wisborg, from Aarhus University Hospital, told New Scientist magazine: "We don't yet know for sure whether stress may directly cause stillbirth, but our results are enough for doctors and midwives to be concerned.

"Thankfully, stillbirth is a rare event. But we still do not know what causes it and any clues we find can help us reduce the risks."

Studies of monkeys suggest that stress hormones might reduce blood flow to the placenta, thereby restricting the supply of oxygen to the foetus.

Although the effect is small, it could tip the balance if the baby has any other problems.

The study only examined the effect of recent increases in stress. Chronic stress may lead to more stillbirths, according to Dr Wisborg.