A pregnant woman at 28 weeks develops fasting hyperglycemia and is diagnosed with gestational diabetes mellitus. Which placental product is the chief mediator of the progressive maternal insulin resistance of late pregnancy?

• A Human chorionic gonadotropin (hCG)
• B Human placental lactogen (hPL) ✓
• C Human chorionic thyrotropin
• D Progesterone-binding globulin

Explanation

Human placental lactogen, also called human chorionic somatomammotropin, is secreted in rising quantities by the syncytiotrophoblast as pregnancy advances and acts as a growth-hormone-like antagonist of maternal insulin, sparing glucose and amino acids for the fetus. Its output correlates with placental mass, explaining why insulin resistance peaks near term. hCG sustains the corpus luteum early on and has no major anti-insulin action.

Reference: Ganong's Review of Medical Physiology, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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