Maternal hypercalcemia as a possible cause of unexplained fetal polyhydramnion: a case series

This study was undertaken to present a possible association between maternal hypercalcemia and fetal polyhydramnion.

Five cases of maternal hypercalcemia were diagnosed with otherwise unexplained fetal polyhydramnion. Cases are outlined; maternal and fetal/neonatal investigation, treatment, and outcome are presented.

Fetal polyhydramnion was identified sonographically (mean amniotic fluid index = 32 +/- 11.3 cm). Maternal hypercalcemia (mean 12.8 +/- 1.1 mg/dL) led to the diagnosis of primary hyperparathyroidism. Of the 5 women, 4 underwent parathyroidectomy. One had a hypercalcemic crisis and intrauterine fetal demise. Neonatal hypercalcemia of remaining infants was documented (mean 13 +/- 1 mg/dL), with subsequent hypocalcemia in 1 of the neonates. All mothers and the 4 live neonates were discharged in good condition.

We suggest that fetuses exposed to a hypercalcemic environment may have polyuria develop similar to adult hypercalcemic polyuria, leading to fetal polyhydramnion. Maternal serum calcium levels may be part of the investigation in otherwise unexplained polyhydramnion, as maternal hypercalcemia may threaten the health of both mother and fetus.