Taking aspirin during pregnancy could reduce the risk of a potentially serious complication, researchers said today.
Scientists, from the University of Sydney in Australia, who analysed the results of 31 trials involving more than 32,000 women found evidence that the drug protects against pre-eclampsia, which is potentially life-threatening to mother and baby.
The condition, which appears to be caused by a defect in the placenta and is usually associated with high blood pressure, affects between 5% and 8% of pregnancies. It may cause abdominal pain, headaches and swelling.
Serious cases of pre-eclampsia kill an estimated 10 women a year in the UK and up to 1,000 babies.
The new research, led by Dr Lisa Askie, showed that the risk of developing pre-eclampsia, delivering before 34 weeks, and having a pregnancy with a severe adverse outcome, fell by 10% in women taking aspirin or antiplatelet drugs, which like aspirin prevent blood clotting.
What causes pre-eclampsia remains unclear, but it may arise from complications that lead to irregular blood flow to the placenta, causing blood clots and death to the tissue. This can lead to the activation of platelets - clotting agents in the blood - and an imbalance between the hormones which promote and slow blood flow. Antiplatelet agents such as aspirin are thought to prevent pre-eclampsia by redressing this balance.
Their findings, reported in an online edition of The Lancet medical journal, concluded: "Our data show that antiplatelet agents produce moderate but consistent reductions in pre-eclampsia and its consequences. This information should be discussed with women at risk of pre-eclampsia to help them make informed choices about their antenatal care."
In an accompanying comment, US experts Professor James Roberts and Dr Janet Catov, from the University of Pittsburgh, wrote that pre-eclampsia was almost a certainty in women who have experienced pre-eclampsia in more than one pregnancy or women with chronic hypertension and pre-eclampsia in a previous pregnancy and "in these settings, aspirin is justified," they said.
"In the more usual setting of risk at about 20%, as in chronic hypertension, multiple gestations, pre-pregnancy diabetes or pre-eclampsia in one previous pregnancy, whether benefits outweigh theoretical long-term risks is more difficult to judge," they added.
They add: "Is treating 50 women to prevent one case of pre-eclampsia or one preterm birth worthwhile? Although from a public health perspective, such a number to treat might seem effective, the decision is one that is probably best made individually in consultation with an informed mother."
