Tragically, around 23 per cent of women are prescribed the drug for the first time only after they become pregnant, say researchers from the Lausanne University Hospital in Switzerland.

Heart defects and problems with the central nervous system (CNS) are some of the more common birth defects that are caused by the drug.

The risk is highest in women who take the drug during their first trimester, even though most of the women who took part in the study had stopped taking the drug six weeks into their pregnancy.

Researchers compared the birth outcomes of 164 women taking Lyrica while pregnant and compared them to 656 pregnant women who were not taking any anti-seizure medication. Six per cent of the women taking the drug gave birth to a child with major defects, and this compared to just 2 per cent in the non-drug group.

Of the women taking Lyrica, 115 were prescribed it for neuropathic pain, 39 for psychiatric disorders, including depression, anxiety, bipolar disorder and psychosis, five were taking it for epilepsy and one was prescribed it for restless leg syndrome.

Seventy-seven per cent had been taking the drug before they became pregnant—which means that the other 23 per cent were prescribed it after they became pregnant.

Lyrica has been approved as a treatment for epilepsy, fibromyalgia and neuropathic pain, although it is also prescribed ‘off-label’—which means for conditions for which its efficacy and safety haven’t been tested—for anxiety and other mental health problems.

Pfizer, its manufacturer, was fined $2.3bn for ‘off-label’ abuse in 2009.