The clinical expression and impact of multiple endocrine neoplasia 1 during pregnancy

Multiple endocrine neoplasia type 1 (MEN 1) is characterized by multisystem neoplasia including primary hyperparathyroidism and pituitary adenoma. Despite the adolescent onset of endocrinopathies, information regarding the impact of maternal MEN 1 on pregnancy is limited to case reports.

To explore pregnancy outcomes in MEN 1 positive women.

Retrospective case series of maternofoetal outcomes MEN 1 positive mothers managed at the Royal Hobart Hospital between 1967 and 2018. Data were retrieved from medical records and Australian averages calculated based on the Australian Institute of Health and Welfare data.

Twenty-six women with MEN 1 were identified accounting for 96 pregnancies and 76 live born infants. Hyperparathyroidism was evident in 16 pregnancies. A significant increase in serum calcium in the second trimester (β = 0.14, P < .001) occurred that was not mediated by parathyroid hormone. Hypercalcaemia was mild-moderate with parathyroidectomy or medical management required in one and four pregnancies, respectively. Compared to the Australian average, women with MEN 1 were more likely to develop gestational diabetes (56% vs 8.9%, P = .001), hypertensive disorders (25.9% vs 7.6, P = .018), have shorter gestations (38.1 vs 38.7 weeks, P = .015) and have low birthweight infants (30.1% vs 6.5%, P = .001). However, emergency caesarean deliveries (63.2% vs 52.3%) and miscarriage rate (20.8% vs 20%) were not significantly different.

Maternal MEN 1 is associated with an increased risk of gestational diabetes, hypertensive disorders and low neonatal birthweight, but not with an increased miscarriage rate. Whilst hypercalcaemia worsens during the second trimester, most pregnancies progressed without overt complications or requirement for intervention.