Lithium Toxicity in Pregnant Swine

Twenty-three pregnant swine were fed either 2.3 kg of a ration containing 2818 kcal metabolizable energy kg^-1 once daily or fed the same ration supplemented with 3000 mg Li₂CO₃ kg^-1 and fed ad libitum during the final 80 days of gestation. Lithium was not fed during lactation. Lithium-fed females voluntarily consumed 2.8 kg day^-1. Swine that consumed lithium lost 27 kg of body weight during gestation and weighed less (P < 0.05) than control females at 110 days of gestation. All of the control females gave birth to piglets but only 58% of the lithium-fed females completed pregnancy. Females consuming lithium gave birth to fewer (P < 0.05) live piglets, more (P < 0.01) mummies and stillbirths and lighter (P < 0.01) litters. Fewer (P < 0.01) of the liveborn piglets born to lithium-treated females survived to 21 days of age. It is suggested that lithium caused these toxic effects by interfering with absorption or metabolism of dietary nutrients. This resulted in mobilization of maternal body stores and caused inadequate development of the fetus or placenta. These data also demonstrate that short-term gestation studies with rats and mice may not be applicable to humans.