Newborn with lithium levels in toxic range. Should we stop breastfeeding?

Lithium is a common part of the treatment for bipolar disorder. It is excreted through breast milk, and traditionally, mothers undergoing this treatment were advised to discontinue breastfeeding due to the potential serious adverse effects of this medication on the infant. More recently, it has been demonstrated that plasma lithium levels in exposed children are generally low and well tolerated, so, in selected cases, breastfeeding can be maintained, and close clinical and analytical monitoring of the child can be conducted, including measurement of thyroid and renal function, and serial lithium levels. We present a clinical case of a full-term newborn, born to a mother with bipolar disorder receiving lithium treatment, exclusively breastfed on demand, who in the second week of life showed toxic levels of lithium in plasma with no symptoms. Careful investigation of the case revealed that the elevated lithium levels were falsely elevated due to incorrect collection of the blood sample in a container containing lithium-heparin as an anticoagulant. The circumstances of the case will be reviewed as well as current recommendations on lithium intake by mothers and breastfeeding of their children.