In a linked research paper (doi:10.1136/bmj.e7085), Bodén and colleagues analysed the risks for the fetus associated with treated and untreated bipolar disorder during pregnancy.1 They found that women with untreated bipolar disorder were at increased risk of producing offspring with microcephaly and neonatal hypoglycaemia, and that infants born to women who are treated with mood stabilisers during pregnancy were at slightly increased risk of preterm birth and congenital anomalies. How should these findings be interpreted?

Previous research has shown that the offspring of women with bipolar disorder have increased rates of memory and attention disturbances, impaired social functioning, behavioural and emotional problems, and even severe psychiatric disorders.2 Severe maternal psychiatric disorders, such as bipolar disorder, are therefore considered to be “teratogenic conditions.”3 Microcephaly has been associated with delayed growth and development, epilepsy, hypotonia, spastic hemiplegia, altered balance and coordination, intellectual impairment, and hyperactivity.4 Recurrent episodes of neonatal hypoglycaemia are strongly correlated with persistent neurodevelopmental and physical growth deficits until 5 years of age,5 severe mental retardation, and epilepsy.6

Bodén and colleagues estimated the risk of …