Uptake and transfer of lithium in pregnancy and lactation in the mouse

The uptake of lithium in pregnant and lactating mice as well as its transfer to their respective fetuses (18-day postcoitum) and nurslings (11- to 15-day postnatal) were quantified. Lithium carbonate in concentrations of 1 or 2 mg/ml given ad libitum in drinking water produced plasma levels in adults ranging from 0.46 to 1.7 meq/liter. In pregnancy, plasma lithium of the adult was twice that of the fetal plasma. However, there was no statistical difference in brain lithium content between adults and fetuses at the 1- or 2-mg dosage. A significant decrease in bone lithium content was found in fetuses as compared to adults at the 2-mg level. During lactation the plasma lithium of nurslings was one-fourth to one-sixth that of the mothers' plasma. Lithium content in brain and in bone of adults was significantly lower than those of nurslings at both drug concentrations. No apparent effects on adults, fetuses, or nurslings were noted in the short term.