Women taking commonly used drugs for anxiety and insomnia before they conceive may be at greater risk of having an ectopic pregnancy.
Around one in every 90 pregnancies in the UK is ectopic, meaning it comes to an end because the fertilised egg gets stuck and does not enter the womb.
Women who take benzodiazepine drugs – which include brands such as Valium – typically to sleep or relieve anxiety, are almost 50 per cent more likely to lose their pregnancy this way.
The finding comes from a study of almost 1.7million women, of whom about one per cent had at least two prescriptions for benzodiazepines in the 90 days before they conceived. Ectopic pregnancies can be life-threatening for women, as the fertilised egg often remains in one of their fallopian tubes, where it can burst or damage the tube and in rare cases cause internal bleeding.
Women taking commonly used drugs for anxiety and insomnia before they conceive may be at greater risk of having an ectopic pregnancy
Dr Elizabeth Wall-Wieler, who led the research from Stanford University School of Medicine, said: ‘For women with specific health conditions such as anxiety or insomnia, benzodiazepines can be an important part of treatment, yet a lot is unknown about how safe it is to use these drugs for women who become pregnant.
‘This study shows that women who use benzodiazepines when they become pregnant are at higher risk of having an ectopic pregnancy.’ Ectopic pregnancies are responsible for up to 13 per cent of pregnancy-related deaths.
The study, published in the journal Human Reproduction, looked at 1,691,366 pregnancies between 2008 and 2015. Almost 18,000 of these pregnancies were in women who had at least two prescriptions for benzodiazepines, for at least ten days of pills, in the 90 days before conceiving.
Benzodiazepine use in pregnancy is also linked to miscarriage and poor child development
These women were 47 per cent more likely to have an ectopic pregnancy than women not prescribed benzodiazepines.
The drugs reduce signalling between brain cells, to make people feel more relaxed, but unfortunately the same signals are used by cells in the Fallopian tubes.
Experts believe they may reduce muscle movement in these tubes, so they are less able to transport a woman’s egg to her womb. If this does not happen, it could wrongly be fertilised in the tube and get stuck there.
Benzodiazepine use in pregnancy is also linked to miscarriage and poor child development.