Conversely, women with a very low body-mass index have a decreased risk of gestational hypertension. A curious but consistent finding is that women who smoke cigarettes have a lower risk of preeclampsia than women who do not smoke, even when confounders are carefully excluded. The babies of cigarette smokers are smaller than those of nonsmokers, presumably because of tobacco-related interference with the transfer of placental nutrients, and their average blood pressures are lower. Multiple pregnancy doubles the risk of preeclampsia. The placental mass is large in both diabetes and multiple pregnancy, and the placenta is at the heart of the problem.
Delivery is the ultimate cure.
Hypoxia or reperfusion injury during placentation might account for the endothelial damage that is increasingly recognized as playing a part in the pathogenesis of preeclampsia. Environmental factors may also contribute to the development of preeclampsia. For example, the high incidence of preeclampsia in many poor countries suggests that an inadequate diet may be a risk factor. The dietary inadequacies that have been proposed as relevant include deficiencies of calcium, zinc, vitamins C and E, and n-3 essential fatty acids. Recommendations for a sensibly balanced diet during pregnancy should be part of routine antenatal care.