Endocrine Abstracts

JOINT1434

Rationale: Pregnancy induces profound metabolic adaptations to support fetal development, including increased insulin resistance and significant hormonal changes. However, when insulin production is inadequate to overcome pregnancy-induced insulin resistance, glucose impairment may occur thus increasing the risk of developing gestational diabetes mellitus (GDM). Emerging evidence highlights the role of early biomarkers, including hormonal profiles, in predicting GDM risk. Prolactin (PRL) plays a pivotal role in these adaptive changes, particularly in glucose homeostasis.

Objective: This study aimed to investigate the trajectory of PRL levels during pregnancy and their association with metabolic and glycemic outcomes.

Methods: A total of 120 pregnant women (67 with GDM, and 53 healthy controls) were assessed for anthropometric, hormonal (serum PRL) and metabolic parameters, including HbA1c, fasting glucose and glucose levels during the oral glucose tolerance test (OGTT). Women diagnosed with GDM underwent a follow-up OGTT between 4 and 12 weeks postpartum.

Results: PRL levels progressively increased across pregnancy but were significantly lower in patients with GDM, particularly in the third trimester (P=0.027). Early pregnancy PRL levels negatively correlated with fasting glucose (P=0.02; r=-0.4), whereas second-trimester PRL levels were inversely correlated with HbA1c levels in both the second (P=0.035; r=-0.5) and third trimesters (P<0.001; r=-0.9), respectively. Lower third-trimester PRL levels were associated with higher pre-pregnancy (P=0.02; r=-0.3) and postpartum weight (P=0.01; r=-0.6), whereas higher PRL levels correlated with better metabolic outcomes and longer breastfeeding duration. Subsequently, women were stratified into two groups based on the median third-trimester PRL level (183.8 μg/l). Ninety-six % of women with PRL<183.8 μg/l developed GDM, compared to 62% of those with PRL>183.8 μg/l (P<0.001). A one-unit decrease in third-trimester PRL predicted a 0.301-unit increase in 2-hour OGTT glucose (P=0.016; t=-2.81), reinforcing its potential role in GDM risk prediction. Adverse outcomes, including preterm delivery<37 weeks (5%) and infants large (LGA, 2.5%) or small (SGA, 5%) for gestational age, rarely occurred. No significant difference emerged between groups in breastfeeding duration, neonatal weight or length. Among patients retested after pregnancy, 22.3% had impaired glucose regulation, including 1 (1.5%) with type 2 diabetes mellitus, 7 (10.4%) with IFG and 7 (10.4%) with IGT.

Conclusions: PRL might represent a valuable biomarker for GDM risk stratification and maternal cardiometabolic health assessment during pregnancy. A sustained increase in PRL levels appears to support glucose homeostasis, whereas lower PRL levels are associated with increased GDM risk. Early monitoring of PRL levels could help identify women at high-risk, enabling timely interventions to improve maternal and fetal outcomes.