Objective The Lifestyle Interventions for Expectant Moms (LIFE-Moms) Consortium is designed to determine, in pregnant women with overweight or obesity, whether various behavioral and lifestyle interventions reduce excessive gestational weight gain (GWG) and subsequent adverse maternal and neonatal outcomes and obesity in offspring. The design and planning process of the LIFE-Moms Consortium is described. Methods The LIFE-Moms Consortium is a collaboration among seven clinical centers, a Research Coordinating Unit, and the NIH designed to support each clinical center's conduct of a separate trial of a unique intervention. Specific common measures, procedures, and eligibility criteria are consistent across the seven trials allowing data to be combined in exploratory analyses and/or compared readily. Results Numerous committees and working groups were created to define common measures and outcomes during pregnancy and through 1 year postpartum, develop Consortium policies, and oversee progress of the trials. The primary outcome for the Consortium is excessive GWG. Secondary outcomes include maternal, neonatal, and infant anthropometric measures, physical activity, sleep, and complications of pregnancy and delivery. Conclusions A multi-center consortium of independent, lifestyle interventions with common measures and outcomes may enhance the ability to identify promising interventions for improving outcomes in pregnant women and their offspring.