Endocrine Abstracts

Context: Prolactin (PRL) exerts a crucial role in the regulation of mammalian reproduction and in the promotion of lactation as response to the suckling reflex. Beyond this, it directly modulates gluco-insulinemic metabolism.ObjectiveTo dissect glucose metabolism during and after pregnancy in patients with chronic hyperprolactinemia (CTPE).MethodsThis longitudinal study included 52 reproductive aged women with CTPE due to pituitary adenomas (43 microadenomas, 9 macroadenomas), chronically treated with cabergoline (CAB) at the mean dose of 0.68±0.6 mg/week for a mean duration of 62.5±52.5 months. 21 out of 52 patients were normal weight (40.3%), 12 overweight (23%) and 8 obese (15.3%). Patients were evaluated before conception, at 12, 24 and 36 weeks of pregnancy and at 1, 2, 3, 4, 5 and 10 years after delivery. CAB was discontinued during pregnancy and restarted in 51.9% of patients after delivery due to recurrent hyperprolactinemia (RH). Anthropometric, hormonal (serum PRL) and metabolic (HbA1c, fasting glucose/FG, glucose tolerance) parameters were assessed.ResultsDuring pregnancy, serum PRL levels were significantly higher than levels before pregnancy (P<0.001), while FG remained stable. An inverse correlation between serum PRL and FG was found in the first (P=0.032) and third (P=0.05) trimester. The percentage increase in serum PRL levels between first and second trimester (Δ1, P=0.048) and first and third trimester (2, P=0.001) were inversely correlated with FG levels at third trimester. Serum PRL before conception emerged as a predictive biomarker of third trimester FG (=2.603; P=0.048). Older age was associated with decreased HbA1c in the first trimester (P=0.048;), reduced infant birth weight (P=0.033), and lower FG at 3 years after delivery (P=0.025;). Breastfeeding up to 6 months after delivery correlated with lower FG at 4 and 10 years postpartum. A positive correlation between pre-pregnancy body mass index and FG at 10 years after delivery (P=0.017) was observed, particularly in overweight/obese patients requiring higher CAB doses. Patients with RH who had to restart CAB showed shorter breastfeeding duration (P=0.04) and higher FG at 2 years after delivery (P=0.015).

Conclusion: An appropriate pre-conceptional metabolic management should be recommended in patients with CTPE to reduce the risk of glucose impairment during and after pregnancy. An excessive reduction in PRL levels due to CAB treatment before conception may predict increased blood glucose levels in the third trimester, which may result in an increased risk of GDM.