Risk Assessment of Diabetes Mellitus during and after Pregnancy in Women with Prolactinomas

Context: Prolactin (PRL) is a crucial mediator of gluco-insulinemic metabolism. Objective: Dissecting glucose metabolism during and after pregnancy in patients with prolactinomas. Methods: 52 patients treated with cabergoline (CAB) were evaluated before conception, during pregnancy and up to 10 years after delivery. During pregnancy, CAB was discontinued, while it was restarted in 57.7 % of patients after delivery, due to recurrent hyperprolactinemia (RH). Hormonal (serum PRL) and metabolic (HbA1c, fasting glucose/FG, glucose tolerance) parameters were assessed. Results: During pregnancy, PRL gradually increased, while FG remained stable. An inverse correlation between PRL and FG was found in the first (p=0.032) and third (p=0.048) trimester. PRL percent increase across pregnancy was inversely correlated with third trimester FG. Serum PRL before conception emerged as predictive biomarker of third trimester FG (τ=2.603; p=0.048). Elderly patients with lower HbA1c at first trimester and lower FG at 3 years postpartum, delivered infants with reduced birth weight. Breastfeeding up to 6 months correlated with lower FG at 4 and 10 years postpartum. A positive correlation between BMI and FG at 10 years after delivery (p=0.03) was observed, particularly in overweight/obese patients requiring higher CAB doses. Patients with RH who had to restart CAB showed shorter breastfeeding duration and higher FG at 2 years postpartum. Conclusions: Low PRL levels before pregnancy may be detrimental to FG during pregnancy. CAB duration and dose may influence long-term glucose tolerance, besides family history and BMI. Pre-conceptional metabolic management should be recommended to reduce the risk of gestational and type 2 diabetes mellitus.