Lithium salts: Grade D. Historical data from the International Lithium Pediatric Registry indicate that lithium causes 400 times more cardiac malformations than normal, including Eisenberg’s syndrome, especially when administered during the first trimester of pregnancy. However, recent observational studies have found that the incidence of Eisenberg’s syndrome and other cardiac malformations due to lithium during pregnancy is 0.05% to 0.1% (note: natural malformation rate 0.005 %). Another prospective observational study with a sample of 183 cases found that lithium salts did not increase the risk of permanent cardiac malformations and only increased the risk of self-limiting cardiac malformations. Although the data are mixed, the current evidence is more supportive of an increased risk of fetal cardiac malformations with lithium salts. The fetal toxicity of lithium salts is also influenced by the peak concentration of the drug, and it is recommended that it be administered 3 to 5 times daily at no higher than 300 mg per dose to reduce peak concentrations. Adverse events in neonates due to lithium salts during maternal pregnancy include: hyperhydramnios, nephrogenic dysuria, thyroid insufficiency, infant hypotonia syndrome, floppybaby, muscle twitching, cardiac arrhythmias, respiratory distress, feeding difficulties, poor sucking, and cyanosis. Adverse neonatal reactions can occur at very low blood levels (0.35 mEq/L), and symptoms usually recover within 1 to 2 weeks. It is thought to be related to neurotoxicity due to high lithium salt concentrations, and some scholars recommend tapering the dose by about 30% from 10 days before delivery. Lithium clearance increases during pregnancy (30-50%) and plasma dissolution increases by 50%, resulting in a significant decrease in drug concentration and triggering symptoms; postpartum vascular volume rapidly decreases by 40%, and a rapid increase in blood concentration may lead to drug toxicity, so it is also recommended to taper the dose by about 30% from 10 days before delivery. If the patient continues to take lithium during pregnancy, it is recommended to monitor the blood lithium concentration (0.6-1 mmol/L) every 4 weeks, weekly after 36 weeks of pregnancy, and more frequently after delivery until the prenatal level is restored, and the drug dose will always be adjusted according to the blood concentration and condition. Lithium salts can be secreted into breast milk and may be concentrated in the milk, which is about 20-30% and up to 50% in the infant, increasing the risk of drug toxicity and adverse effects due to dehydration, infection, and preterm delivery. In general, lithium salts are not recommended during breastfeeding. If you are already taking lithium salts before delivery and breastfeeding, it is usually recommended to change the medication after delivery. If lithium must be used, the infant’s physiological and mental status should be closely observed, and the infant’s body drug concentration, blood electrolyte concentration, thyroid function, and renal function should be monitored. It is also recommended that the mother and child stay in the hospital for a few more days after delivery to facilitate observation. Other considerations regarding the administration of lithium salts, such as what tests should be done when during pregnancy, genetic counseling, etc.