Lithium use during pregnancy
Ideally, the management of a patient taking lithium during the perinatal period should be multidisciplinary, with liaison between the general practitioner, psychiatrist, obstetric team and paediatrician. The patient should have a clear childbirth plan that is shared with the multidisciplinary team. If possible, delivery should take place in a tertiary hospital with a specialist neonatal care unit and psychiatric team; alternatively, seek advice from the patient’s psychiatrist and a paediatrician.
Lithium use during the first trimester has been associated with an increased risk of cardiac malformations (eg Ebstein anomaly); however, the absolute risk of malformations appears low. Although limited data suggest that lithium does not increase complications at the time of delivery or affect long-term neurodevelopmental outcomes, increased rates of neonatal complications have been reported.
If a patient becomes pregnant while taking lithium, do not abruptly stop it; urgently seek advice from a psychiatrist to help decide upon the approach—see here for guiding principles. Abruptly stopping lithium dramatically increases the risk of relapse in bipolar disorder and in turn fetal harm; for advice on managing bipolar disorder during pregnancy, see here.
Breastfeeding while taking lithium is not recommended; this may influence the decision to continue lithium—see also Principles of psychotropic use while breastfeeding. If the decision is made to switch to another drug, it is preferable to switch well before birth is expected; if lithium is used for bipolar disorder, see Considerations in managing bipolar disorder during pregnancy for guidance. If lithium was stopped because of teratogenicity concerns, it can be restarted in the second trimester. If a patient has taken lithium while pregnant, encourage them to have a high-resolution ultrasound and fetal echocardiography at 18 to 20 weeks to detect cardiac malformation.
[NB1] [NB2]
Remind the patient of signs of lithium toxicity and the importance of maintaining adequate hydration.
Check kidney function and blood lithium concentration every 4 weeks during pregnancy until 34 weeks gestation, and weekly thereafter. Consider more frequent monitoring if hyperemesis gravidarum or nausea and vomiting are problematic.
Check thyroid function at 12, 24, 36 and 40 weeks gestation.
Encourage the patient to have a high-resolution ultrasound and fetal echocardiography at 18 to 20 weeks to detect cardiac malformation.
At admission to hospital for delivery:
- check kidney function and blood lithium concentration
- withhold lithium until delivery [NB3]
- consider administering intravenous hydration.
If intrapartum complications (eg haemodynamic instability) occur, check intrapartum blood lithium concentration.
Immediately after delivery:
- check the patient’s kidney function and blood lithium concentration
- check cord blood lithium concentration and thyroid stimulating hormone (TSH) and T4 concentrations
- seek paediatric assessment of the neonate for lithium-associated complications and toxicity
- restart lithium under expert advice; because of the high risk of relapse, aim for a blood lithium concentration of 0.8 to 1.0 mmol/L for the first 4 weeks postpartum; check the concentration twice a week for the first 2 weeks. At 4 weeks postpartum, return to the prepregnancy dosage and target lithium concentration.
NB1: Ideally, the management of a patient taking lithium during the perinatal period should be multidisciplinary, with liaison between the general practitioner, psychiatrist, obstetric team and paediatrician. The patient should have a clear childbirth plan that is shared with the multidisciplinary team. If possible, delivery should take place in a tertiary hospital with a specialist neonatal care unit and psychiatric team; alternatively, seek advice from the patient’s psychiatrist and a paediatrician.
NB2: Kidney clearance increases during pregnancy and decreases over a period of 2 weeks following delivery, with parallel changes in lithium concentration and, potentially, effectiveness.
NB3: Vascular volume rapidly reduces immediately after birth—to reduce the risk of toxicity, withhold lithium at the onset of labour, or for 24 hours before a planned caesarean section. Do not routinely reduce the dosage of lithium before delivery because this increases the risk of relapse.