The increasing prevalence of overweight and obesity among women of childbearing age is a growing public health concern in the United States. The average body mass index (BMI) is increasing among all age categories and women enter pregnancy at higher weights. Women are also more likely to retain gestational weight with each pregnancy. Women who are overweight (BMI 25-30) and obese (BMI >/=30) are at greater risk of adverse reproductive health outcomes compared to women of normal weight status (BMI 19.8-25). This article provides an overview of the complications associated with maternal overweight and obesity including diabetes, pre-eclampsia, c-sections, and birth defects. We present updated information on the weight trends among women. Finally, we present an overview of the prevention studies aimed at adolescents and women prior to pregnancy.