Pregnancy outcomes in women with primary hyperparathyroidism.

OBJECTIVE: To study pregnancy and pregnancy outcomes in women with primary hyperparathyroidism (PHPT) and in controls.

DESIGN: Register-based retrospective cohort study of women aged 16-44 years with a diagnosis of PHPT with age- and gender-matched non-exposed controls in Denmark.

METHODS: The patients and controls were identified using the Danish National Hospital Discharge Register for the period 1977-2010. The outcomes were determined using the Birth Register, the Abortion Register and the LPR (National Hospital Discharge Register). The primary outcome was the relative risk of abortions in patients compared with controls.

RESULTS: A total of 1057 women with PHPT and 3171 controls were identified. The number of women giving birth and experiencing abortions did not differ between the two groups (live births, P=0.21 and abortions, P=0.12). Also birth weight, length, Apgar score, and gestation length at abortion did not differ. Within the first year after the diagnosis was made, gestation length was lower in women with PHPT than that in controls. However, this was linked to more deliveries by caesarian sections.

CONCLUSIONS: A diagnosis of PHPT did not seem to increase the rate of abortions in our study. Reducing the abortion risk may therefore not be an indication for parathyroidectomy during pregnancy in patients with mild PHPT. The PHPT diagnosis does not seem to affect birth weight, length and Apgar score. The higher number of deliveries by cesarean section after the diagnosis was made may be associated with lower gestation age. The strategy for delivery should be carefully considered in pregnant women with PHPT.