The risks of taking lithium during pregnancy

The mood stabiliser lithium is a proven, effective treatment for bipolar disorder and serious depression. Bipolar disorder affects an estimated 2% of the worlds population. However, for women taking the drug during pregnancy, there are known to be risks to the unborn child.

In fact, a recent study has shown that 7.4% of children exposed to the drug during the first three months of the pregnancy go on to be born with “major malformations”. This is compared to 4.3% of babies when the mother didn’t take lithium; making them one and a half times more likely to develop defects.

When looking at “major malformations, the researchers, who were based in Denmark, the US and the UK, included “neural tube defects” including spina bifida, as well as defects that affected the development of the genitals and urethra and heart conditions. This echoes the results of a major study last year into the risks of lithium on pregnant women, which suggested that it could drastically increase the risk of serious heart defects.

This study, which is the largest to date of the risks of lithium, looked at data from pregnancies in six different countries. In 727 of the pregnancies, the children were exposed to lithium; they also looked at 21,397 pregnancies in which the mother had bipolar disorder but stopped taking the drug.

In the group that didn’t take lithium, 856 developed malformations. In the babies that were exposed to lithium in the first three months of pregnancy, 47 suffered from major birth defects: which is an increase of 71%. It was also found that newborns that were exposed to the drug during pregnancy had nearly double the risk of being readmitted to hospital within 29 days of birth.

Senior author of the study, Professor Veerle Bergink from the Icahn School of Medicine and Mount Sinai in New York, noted that despite these risks, lithium is a very effective treatment for the symptoms of bipolar disorder. Therefore, the decision of whether to stop treatment or lower the dosage in pregnant women, should still be considered a clinical decision.

Professor Bergink added: “Women should be informed on malformation risk in first-trimester exposed infants, but also about very high relapse risks for mental illness both during pregnancy and during the postpartum period.” The authors conclude that: “Lithium treatment decisions are key and need to be encouraged before conception. In particular, first-trimester lithium use should be cautioned and decided upon on the basis of the available evidence.”