Pregnant women who take Prozac, the antidepressant, are twice as likely to give birth to babies with a congenital heart problem, the medicines regulator has warned.
The Medicines and Healthcare products Regulatory Agency (MHRA) said there was a “possible small risk” of congenital heart defects if women were given the drug in early pregnancy.
The agency said it had looked at the evidence from a number of studies of fluoxetine, the active ingredient in Prozac, and concluded that it could double the background rate of congenital heart defects.
About one in 100 babies are typically born with a problem such as a heart murmur, hole in the heart or other problem with the organ’s structure or rhythm.
But the MHRA estimates this rate increases to almost two in 100 pregnancies among women prescribed fluoxetine, which is a similar rate to another common antidepressant, Seroxat (paroxetine).
The drugs are part of a group known as selective serotonin reuptake inhibitors (SSRIs), which are not recommended to be taken during pregnancy because of the risk of withdrawal symptoms in the developing baby.
But it is estimated that 2.3 per cent of pregnant women each year are prescribed SSRIs when the benefits are considered to outweigh the risks.
Studies suggest that up to one in five mothers-to-be suffer from depression at some point during pregnancy, which if left untreated can cause low birth weight and premature birth.
The MHRA said that a class effect with SSRIs on heart formation in utero “could not be excluded” and recommended GPs were mindful of this when prescribing the drugs.
The agency said: “When prescribing fluoxetine to treat depression during pregnancy, prescribers should be aware that there may be a small increased risk of congenital cardiac defects in infants exposed in early pregnancy, similar to that seen with paroxetine.”