During pregnancy, sudden weight gain and an increase in certain hormones can cause a type of temporary diabetes called gestational diabetes. In this type of diabetes, the body can’t make enough insulin fast enough, or use it as effectively as before. This second response is known as “insulin resistance”, and women who enter pregnancy overweight are more likely to experience it. Also called “metabolic syndrome”, this failure to keep up with the demands pregnancy puts on a woman’s body, is one of the first indicators of prediabetes. But weight isn’t the only factor. The chances of developing gestational diabetes also increase if the woman has a parent, sister or brother with diabetes; if the fetus is exceptionally large (nine pounds plus); or if she is Hispanic/Latina, African American, Native American, Asian American, or Pacific Islander. These ethnic groups all share “feast or fast” genes, which – put in a permanent state of “feast” by Western diets – are no longer able to regulate insulin production. The most vulnerable populations are Puerto Rican, Mexican American, and Native American. A final risk factor for gestational diabetes is polycystic ovary syndrome, or PCOS, a hereditary disease characterized by hormone imbalances, notably androgen. Doctors can help control gestational diabetes by prescribing medications to keep blood sugar under control. They will also recommend low-carbohydrate diets, and regular exercise. Gestational diabetes ordinarily disappears as soon as the baby is delivered, or very shortly thereafter. However, among at-risk populations, diabetes may return, years or even decades later, as full-blown type 2 diabetes. And when it does, it may be doubly difficult to bring under control again. Babies born to mothers with gestational diabetes are likely to develop jaundice or difficulty breathing, and face a greater risk of death both immediately before and after birth. They may also face a lifelong struggle with weight, and are highly prone to type 2 diabetes themselves. Breastfeeding, in addition to maternal blood sugar control, can offset these immediate and future risks of developing diabetes.