Protocol for a randomised controlled trial of a weight maintenance intervention to promote fat loss in pregnant individuals with obesity

Abstract

Introduction: In pregnancy, people with obesity or excess adiposity are prone to excess gestational weight gain (GWG) and have the highest risks for multiple maternal morbidities. Epidemiological studies suggest that the lowest incidence of adverse maternal and infant outcomes occurs with GWG lower than current recommendations (<5 kg) and with gestational weight maintenance, resulting in fat mass loss, in those with obesity. Data from randomised clinical trials are needed to evaluate the efficacy of a fat mass loss intervention on pregnancy outcomes. The objective of this proof-of-principle randomised controlled trial is to test the effect of a gestational fat mass loss intervention in pregnant individuals with obesity on changes in weight, fat mass and cardiometabolic disease risk factors.

Methods and analysis: In this two-site randomised parallel group, 100 women (30% black; 30% Hispanic) with pre-existing obesity (31.0≤body mass index≤55.0 kg/m²) are randomised to usual care (Provider Directed Group) or usual care plus a fat mass loss intervention with food provision (Weight Maintenance Group). The primary outcomes of the trial (Healthy Mamas/Mamis Saludables) are weight, fat mass (via three-compartment model) and cardiometabolic disease risk factors (ie, blood pressure, lipids, glucose, insulin) from baseline (~13 weeks gestation) to ~35 weeks gestation and at 2 weeks postpartum. Secondary aims evaluate the safety of the fat mass loss intervention during pregnancy and test the hypotheses that compared with usual care, the intervention will have no significant adverse effect on fetal growth, neonatal size, infant body composition and other adverse events. Mediators (eg, eating, activity) and moderators (eg, parity, obesity grade, race/ethnicity) of intervention effects are also examined. Finally, the study will explore the effect of prenatal fat mass loss on reducing the incidence of adverse obstetrical outcomes, including non-elective caesarean delivery, gestational diabetes, hypertension and pre-eclampsia.

Ethics and dissemination: The trial has been approved by the Pennington Biomedical Research Center Institutional Review Board, is monitored by an independent data and safety monitoring board and will be conducted in agreement with the Declaration of Helsinki. All results, positive, negative and inconclusive, will be disseminated at national and/or international scientific meetings and in peer-reviewed scientific journals.

Trial registration number: NCT04731688.

Keywords: NUTRITION & DIETETICS; Obesity; Pregnancy; Pregnant Women; Randomized Controlled Trial.

Figure 1. Healthy Mamas/Mamis Saludables clinical trial design. Example weight trajectories for individuals randomised to Usual Care vs Weight Maintenance Groups. GWG, gestational weight gain.

Figure 2. Healthy Mamas/Mamis Saludables multicomponent behavioural intervention.