Pregnant women taking anxiety drugs 'are 70pc more likely to miscarry'
Pregnant women prescribed sleep and anti-anxiety medication may be at greater risk of miscarriage, a study suggests.
Researchers in Taiwan analysed more than three million pregnancies from nearly two million women and found that those prescribed the drugs were 70 per cent more likely to miscarry.
Fewer than 1 per cent of pregnant women in Britain are offered the sedatives such as diazepam or lorazepam each year to help with insomnia or anxiety disorders.
But it still means tens of thousands of women are being prescribed the drugs while pregnant.
The drugs are sold under brand names such as Valium and Xanax but the study, published in Jama Psychiatry, did not specify which had been taken.
In the research, around 4.4 per cent of women had miscarriages with fludiazepam found to more than double the risk. Alprazolam had the lowest risk at 39 per cent.
Experts from National Taiwan University concluded: “Benzodiazepine use during pregnancy was associated with an increased risk of miscarriage, even after accounting for unmeasured confounders, including those related to genetics and the family environment.
“The observation of an increased risk of miscarriage associated with benzodiazepine use during pregnancy suggests that benzodiazepines should only be used after a thorough evaluation of the potential benefits and risks for both the mother and child.”
Cause and effect questioned
British experts warned that benzodiazepine use should be kept as low as possible, but said that other reasons could be driving the link between the drugs and miscarriages, such as underlying conditions which needed medication.
Prof Sir Simon Wessely, regius chairman of psychiatry at King’s College London, said: “It’s well conducted with big numbers, and I am in no doubt that they found an association. But the big question is, is this cause and effect? And the problem is we can’t tell.
“There may be plenty of reasons why someone is being prescribed benzodiazepines and is also at higher risk of miscarriage.
“They did the best they could to control these, and the association remained, but it’s always an issue in this kind of study. The main lesson is that for lots of reasons we should continue all efforts to reduce the prescriptions of benzodiazepines anyway, especially for anything more than a very short period.”
There have been several studies linking benzodiazepines to pregnancy complications in recent years.
In 2020, Stanford University found that women who take the sedatives in the weeks before conception were 50 per cent more likely to have an ectopic pregnancy.
In 2019, a British study found women were at 60 per cent more risk of spontaneous abortion if they took benzodiazepines in early pregnancy. But not all experts are convinced.
Prof Christiaan Vinkers, psychiatrist and stress and resilience chairman at Amsterdam University Medical Centre, added: “I think these results have a large risk of confounding by indication, i.e. patients with mental health problems receiving more benzodiazepines.
“Benzodiazepine use is very broadly defined, and more stringent definitions lead to attenuated associations. Without a plausible mechanism, and pharmacological assumptions about short-acting vs long-acting that are untenable, it seems to me that this study should not change current practice.
“Of course, we should always be prudent during pregnancy with any medication use. However, anxiety and severe insomnia undoubtedly also have detrimental effects on the mother and unborn child.”
