Neonatal lithium toxicity as a result of maternal toxicity

Lithium carbonate is used for the treatment of bipolar disorder. Because of its widespread use, many women of childbearing age are taking lithium carbonate, which belongs to the US FDA Category D. Administration during pregnancy can result in fetal toxicity. A 17-y-old female with pre-eclampsia and a history of manic depression gave birth to an infant at 37-w gestational age. Several hours prior to delivery, the mother had a lithium level of 2.6 mEq/L. The infant's initial lithium level after birth was 2.1 mEq/L. A subsequent lithium level on the 3rd d of the child's life was 1.4 mEq/L; the half-life in the infant was > 24 h. During the first 4 d of life, the infant was lethargic and exhibited poor suck-swallow coordination that required supplemental enteral feeding. By the 7th d of life, the infant was alert and tolerating all oral feedings. Lithium carbonate readily crosses the placental barrier and can produce teratogenic effects and toxicity. Neonates exposed in utero should be carefully monitored for symptoms of toxicity. In this case only minor toxic effects occurred.