After a pregnancy with gestational diabetes, a 75 g oral glucose tolerance test at about 4 to 12 weeks postpartum is the standard check for persisting diabetes or prediabetes. HbA1c is unreliable this soon after delivery because of pregnancy-related changes in red-cell turnover and blood loss.
If the result is normal, risk does not return to baseline. Lifelong screening every one to three years is the usual recommendation, with lifestyle advice and attention to weight. Breastfeeding is worth encouraging for its own sake.
The weak link is rarely the test choice — it is that the test never happens. Booking it before discharge, or at the infant's vaccination visit, catches women who would otherwise not return.
- Book a 75 g OGTT for 4–12 weeks after delivery in every woman who had GDM.
- Do not rely on HbA1c in the early postpartum weeks.
- Screen every one to three years afterwards, even when the postpartum test is normal.
- Use the infant's vaccination visits as a prompt to check the test was done.
Why it matters
Most missed post-GDM diabetes is a missed appointment, not a missed result.
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