The rates of maternal overweight and obesity, but also excess gestational weight gain, are increasing. Pregnancy complications, including gestational diabetes mellitus, gestational hypertension, pre-eclampsia and delivery of a preterm or growth restricted baby, are higher for both women with overweight and obesity and women who gain excess weight during their pregnancy. Other conditions such as polycystic ovary syndrome are also strongly linked to overweight and obesity and worsened pregnancy complications. All of these conditions place women at increased risk for future cardiometabolic diseases. If overweight and obesity, but also excess gestational weight gain, can be reduced in women of reproductive age, then multiple comorbidities associated with pregnancy complications may also be reduced in the years after childbirth. This narrative review highlights the association between maternal overweight and obesity and gestational weight gain, with gestational diabetes, pre-eclampsia, polycystic ovary syndrome and delivery of a preterm or growth restricted baby. This review also addresses how these adverse conditions are linked to cardiometabolic diseases after birth. We report that while the independent associations between obesity and gestational weight gain are evident across many of the adverse conditions assessed, whether body mass index or gestational weight gain is a stronger driving factor for many of these is currently unclear. Mechanisms linking gestational diabetes mellitus, gestational hypertension, pre-eclampsia, preterm delivery and polycystic ovary syndrome to heightened risk for cardiometabolic diseases are multifactorial but relate to cardiovascular and inflammatory pathways that are also found in overweight and obesity. The need for post-partum cardiovascular risk assessment and follow-up care remains overlooked. Such early detection and intervention for women with pregnancy-related complications will significantly attenuate risk for cardiovascular disease.