10th November 2017, Volume 130 Number 1465

Lithium use in pregnancy and the risk of cardiac malformations

There has been concern that exposure to lithium early in pregnancy may be associated with a marked increase in the risk of Ebstein’s anomaly and other congenital cardiac abnormalities.

As the previous data are conflicting, this cohort study was performed. The study group included over 1.3 million pregnancies. The researchers examined the risk of cardiac malformations among infants exposed to lithium during the first trimester as compared with unexposed infants and, in secondary analyses, with infants exposed to another commonly used mood stabiliser, lamotrigine.

Maternal use of lithium during the first trimester was associated with an increased risk of cardiac malformations, including Ebstein’s anomaly as compared with the unexposed infants. Results were similar when compared to the lamotrigine exposed infants. However, the magnitude of this effect was smaller than had been previously postulated.

N Engl J Med 2017; 376:2245–54

Adverse events associated with statin therapy?

These researchers speculate that adverse events (AEs), particularly muscle pain and weakness, to statins have been overemphasised.

To elucidate this matter, they have reviewed data from two large trials. In a blinded randomised trial treatment when atorvastatin was compared with a placebo, there was no difference in the incidence of muscle-related AEs. However, in a non-blinded non-randomised trial of atorvastatin versus placebo the incidence of muscle-related AEs was significantly higher in those taking the statin.

These analyses illustrate the so-called nocebo effect, with an excess rate of muscle-related AE reports only when patients and their doctors were aware that statin therapy was being used and not when its use was blinded. These results will help assure both physicians and patients that most AEs associated with statins are not causally related to use of the drug and should help counter the adverse effect on public health of exaggerated claims about statin-related side effects.

Lancet 2017; 389:2473–81

Prenatal antidepressant use and risk of attention-deficit/hyperactivity disorder in offspring

Does prenatal use of antidepressants increase the risk of attention-deficit/hyperactivity disorder (ADHD) in offspring?

This population-based cohort study involved nearly 200,000 children. Three percent of them had a diagnosis of ADHD. Children whose mothers used antidepressants in the prenatal period were compared with those of mothers who did not. Children whose mothers used antidepressants before their pregnancy were also compared with non-users.

The incidence of ADHD was increased in those whose mothers used prenatal antidepressants (hazard ratio 1.39). Similar results were found in the children of those treated with antidepressants before pregnancy.

BMJ 2017; 357:j2350