Pregnancy, delivery and neonatal outcomes among women with hypoparathyroidism-A population-based study.

Objective: Data are inconclusive regarding pregnancy complications associated with maternal chronic hypoparathyroidism. Therefore, we aimed to compare pregnancy, delivery and neonatal outcomes in patients affected by chronic hypoparathyroidism to those without chronic hypoparathyroidism.

Design: A retrospective population-based study utilising data from the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (HCUP-NIS) database over 11 years from 2004 to 2014 inclusively. Multivariate logistic regression was used to control for confounders.

Patients: Patients with chronic hypoparathyroidism compared with those without.

Measurements: Obstetric and neonatal outcomes.

Results: We identified 204 pregnancies in mothers with chronic hypoparathyroidism and 9,096,584 pregnancies without chronic hypoparathyroidism. After adjusting for age, insurance plan type, obesity, chronic hypertension, thyroid disease, pregestational diabetes mellitus, and previous caesarean section, patients in the hypoparathyroidism group, compared with those without hypoparathyroidism, were found to have an increased rate of preterm birth (<37 weeks) (19.1% vs. 7.2%, aOR: 2.49, 95% confidence interval [CI]: 1.74-3.54, p < 0.0001, respectively); and blood transfusions (4.9% vs. 1.0%, aOR: 4.07, 95% CI: 2.15-7.73, p < -0.0001). Neonates to mothers with chronic hypoparathyroidism had a higher rate of congenital anomalies (4.4% vs. 0.4%, aOR: 6.50, 95% CI: 3.31-12.75, p < 0.0001), with comparable rates of small-for-gestational-age neonates and intrauterine foetal death.

Conclusion: This is the largest study of chronic hypoparathyroidism in pregnancy to date. We found significant increases in the rates of preterm birth, blood transfusions and congenital anomalies in chronic hypoparathyroidism. Our findings highlight the importance of identifying chronic hypoparathyroidism as a risk factor for pregnancy and neonatal complications, although it remains unknown if maintaining calcium in the target range will mitigate these risks.