Betamethasone-induced hypokalemic periodic paralysis in pregnancy.

BACKGROUND: Acute hypokalemic periodic paralysis may be induced by betamethasone injections during pregnancy.

CASE: A healthy 23-year-old gravid woman at 32 weeks of gestation with preterm premature rupture of membranes received two doses of 12-mg intramuscular betamethasone 24 hours apart to accelerate fetal lung maturation. She developed significant proximal muscle weakness within 16 hours after the initial dose. Her serum potassium was 1.6 mEq/L. Oral and parenteral potassium replacement restored her neuromuscular function over several days. She delivered by repeat cesarean at 34 weeks of gestation without complications for her or the neonate.

CONCLUSION: Hypokalemic periodic paralysis, a rare cause of weakness, may be induced by betamethasone injections during pregnancy and is reversible with low-risk interventions.