ABSTRACT
In normal pregnancy, blood sugar remains within tightly controlled limits, while insulin secretion doubles between the first and the third trimester.1 The reason for this relative insulin resistance is uncertain, but it is likely that many pregnancy hormones, some of which are known to be insulin antagonists, including human placental lactogen, glucagon and cortisol, play a role.2 If insulin secretion cannot increase sufficiently to offset the increase in peripheral insulin resistance, gestational diabetes can develop. This abnormality may be confined to pregnancy or may represent the first manifestation of type 2 diabetes.3
