Fertility and Pregnancy Outcomes in Primary Hyperparathyroidism: Observations From a Large Insured Population

Primary hyperparathyroidism (PHPT) has initially been implicated in adverse maternal and neonatal outcomes, while subsequent population studies have failed to show an association.

This work aimed to compare maternal, pregnancy, and neonatal outcomes in patients with and without PHPT.

A retrospective matched-cohort study (2005-2020) was conducted at an integrated health-care delivery system in Southern California. Women aged 18 to 44 years were included. Patients with a biochemical diagnosis of PHPT were matched 1:3 with eucalcemic controls (non-PHPT). Main outcome measures included achievement of pregnancy, pregnancy outcomes (including rates of abortion, maternal complications), and neonatal outcomes (including hypocalcemia, need for intensive care).

The cohort comprised 386 women with PHPT and 1158 age-matched controls. Pregnancy rates between PHPT and control groups were similar (10.6% vs 12.8%). The adjusted rate ratio of pregnancy was 0.89 (95% CI, 0.64-1.24) (PHPT vs non-PHPT). Twenty-nine pregnancies occurred in women with coexisting PHPT and 191 pregnancies occurred in controls, resulting in 23 (79.3%) and 168 (88.0%) live births, respectively (P = .023). Neonatal outcomes were similar. Live birth rates were similar (86.4%, 80%, 79.2%) for those undergoing parathyroidectomy prior (n = 22), during (n = 5), or after pregnancy/never (n = 24). Among patients who underwent parathyroidectomy during pregnancy, no spontaneous abortions occurred in women entering pregnancy with peak calcium less than 11.5 mg/dL (2.9 mmol/L).

We observed no difference in pregnancy rates between women with or without PHPT. Performing parathyroidectomy before pregnancy or during the second trimester appears to be a safe and successful strategy, and adherence to this strategy may be most critical for patients with higher calcium levels (≥11.5 mg/dL [2.9 mmol/L]).