Polyhydramnios with maternal lithium treatment.

Severe polyhydramnios, probably due to fetal lithium toxicity, is described. The mother had been treated with lithium because of manic-depressive psychosis. The plasma lithium level during the pregnancy was in or below the therapeutic range. From the 26th week of gestation, polyhydramnios developed. In the 35th week, 11.5 L of amniotic fluid was removed over a period of 12 hours by transabdominal amniocentesis. A cesarean delivery was performed in the 39th week of gestation because of fetal distress. The infant presented with the following symptoms, which in previous reports have been associated with lithium toxicity: asphyxia, apnea, cardiac decompensation, respiratory distress, hypoglycemia, thrombocytopenia, diabetes insipidus, hypotonia, and convulsions. The polyhydramnios was probably caused by fetal diabetes insipidus, possibly combined with cardiac decompensation. Lithium can be toxic to the infant and the fetus even though the mother is not affected and has a normal or low plasma lithium level. Polyhydramnios may be a sign of fetal lithium toxicity.