Benzos increase the risk of having a miscarriage in early pregnancy, regardless of whether you’re taking a short-acting one for insomnia or a longer-acting one for anxiety, Canadian researchers say.

According to their large case-controlled study involving almost 450,000 pregnancies, benzodiazepine exposure in early pregnancy was associated with an 85% higher risk of spontaneous abortion compared to pregnancies where that class of drugs were not taken. And this increased risk remained the same, after a whole range of possible confounders had been adjusted for, including maternal mood and anxiety disorders.