Numerous studies have shown that nutritional status during pregnancy has a significant impact on the long-term health of the child born. The developmental origins of health and disease hypothesis proposes that if a child is undernourished during pregnancy, that child will develop diabetes and hypertension in the future if the child is adequately nourished after birth. Furthermore, exposure to hyperglycemia during pregnancy (e.g., gestational diabetes mellitus (GDM) has been reported to cause a variety of complications in the child. In particular, myocardial hypertrophy is a serious complication. We have created a model animal (GDM rat) that is hyperglycemic during pregnancy, and have been studying at the molecular level what kind of abnormalities are seen in the hearts of the offspring. We have also searched for the best nutrition to correct these abnormalities. As a result, we have found that n-3 unsaturated fatty acid EPA intake during pregnancy improves these abnormalities in GDM rats. However, EPA-rich fish contain high concentrations of heavy metals such as mercury and toxic substances. In addition, there is concern that EPA intake by pregnant women may lead to bleeding tendency during childbirth. Therefore, palmitoleic acid, an n-7 unsaturated fatty acid, was examined in a GDM cell model and was found to improve the adverse effects of hyperglycemia. Since trans-palmitoleic acid is found in dairy products, it is considered to be a safe nutrition for pregnant women.