Women's HealthPending review

Gestational diabetes

Placental hormones progressively induce maternal insulin resistance through pregnancy, and gestational diabetes emerges when the pancreas cannot secrete enough extra insulin to compensate, leaving glucose (and its downstream fetal effects) uncontrolled.

In a nutshell

Rising placental hormones make the mother progressively insulin-resistant through pregnancy; gestational diabetes occurs when her pancreas cannot secrete enough extra insulin to compensate. Fetal hyperglycaemia then drives fetal hyperinsulinaemia (Pedersen hypothesis), causing macrosomia and neonatal hypoglycaemia at birth.

Classic presentation

Usually asymptomatic, identified by risk-factor-based OGTT screening at 24–28 weeks, or found incidentally with fetal macrosomia or polyhydramnios on scan.

Key points

Glucose crosses the placenta freely; insulin does not. Fetal hyperinsulinaemia, not maternal glucose itself, drives macrosomia and organomegaly.

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Educational content pending clinical review. Not medical advice.