Association Between Twin Pregnancy and Hyperglycemia in a Multiethnic Community in New Zealand

Human placental lactogen is higher in twin pregnancies than singleton pregnancies. Theoretically, this should increase insulin resistance and risk for gestational diabetes mellitus (GDM) (1). However, twin pregnancy has been found to be associated with a higher incidence of GDM in some studies (2,3) but not others (4,5). Polynesians have a high incidence of GDM (6), and we have investigated whether, in our multiethnic population, twin pregnancies are associated with a greater risk of GDM.

Locally, a universal screening policy using a nonfasting 50-g glucose challenge test (GCT) at 24–28 weeks is advocated (6), and if the fasting glucose is ≥5.5 mmol/l and/or the 2-h post–oral glucose tolerance test (OGTT) 75-g load is ≥9.0 mmol/l, GDM is diagnosed (7). If a suspicion of GDM occurs (e.g., previous GDM or evidence of macrosomia), then direct referral …