Time-restricted Eating Among Pregnant Females With Severe Obesity

In the United States, severe obesity (body mass index (BMI) ≥ 40.0 kg/m2) affects approximately 10% of females of reproductive age with Black females disproportionately burdened (16%). Severe obesity is a significant predictor of adverse perinatal outcomes including gestational diabetes mellitus, pre-eclampsia, premature birth, and at its most severe, fetal death, birth defects and a three-fold greater risk of maternal mortality - outcomes that also disproportionately affect Black females. Observational studies suggest weight maintenance and even modest body fat loss and altering the maternal metabolic milieu (availability of glucose and lipids) in the gestational period may be important to reducing perinatal health risks among pregnant females with severe obesity. The proposed research aims to assess time-restricted eating in the 2nd and 3rd trimesters of pregnancy to explore the effects on maternal weight, and perinatal health outcomes compared to standard clinical care.

Severe obesity is a contributor to adverse perinatal outcomes and Black females are disproportionately burdened. The prevalence of severe obesity is on the rise in the United States (U.S.), having increased from 6.4% of the adult population in 2011-2012 to just over 9% of adults in 2017-2018. The prevalence of severe obesity among reproductive age females is approximately 10%. This is an alarming statistic given severe obesity is a predictor of adverse perinatal outcomes including gestational diabetes mellitus, preeclampsia, premature birth (both spontaneous and medically indicated), and at its most severe, fetal death, birth defects, and a three-fold greater risk of maternal mortality. Observational studies suggest weight maintenance and even modest body fat loss and altering the maternal metabolic milieu (availability of glucose and lipids) in the gestational period may be important to reducing perinatal health risks among pregnant females with severe obesity. Existing lifestyle interventions (calorie control/dietary pattern changes/physical activity) have showed modest effects on attenuating excess gestational weight gain and modest effects on perinatal health outcomes among pregnant females with obesity. Time- restricted eating, where an individual simply watches the clock and consumes calories within a particular eating window, is a simple and highly accessible eating pattern that has the potential to minimize gestational weight gain, reduce excess glucose and lipids, and improve metabolic health among pregnant females with severe obesity all of which could translate to improved perinatal health outcomes. Yet there are no clinical trials of time-restricted eating in pregnancy. The investigators aim to test the safety, feasibility, and acceptability of time-restricted eating among 80 pregnant females with severe obesity. The investigators will examine time-restricted eating safety, feasibility and acceptability (8-hr eating window in the 2nd trimester \& 10-hr eating window in the 3rd trimester), and explore its effects on weight, cardiometabolic risk markers and perinatal health outcomes vs. Standard Care. The intervention will begin at \~17 weeks gestational age and continue through admission for labor and delivery. The study will involve weekly meetings with a nutritionist, and research visits at baseline (\~17 weeks gestational age), 27-29 weeks gestational age and 35-37 weeks gestational age as well as monthly check-ins for maternal and fetal health monitoring. Maternal and neonatal data from labor and delivery will also be collected from electronic health records. Glucose will be continuously monitored for 10 days at 20 weeks gestational age and 34 weeks gestational age (optional). The goal of our work is to reduce and prevent adverse perinatal outcomes among pregnant females with severe obesity. Given the relative simplicity of time-restricted eating it can be easily disseminated in clinic demonstrating its strong potential for wide-scale public health impact.

Eligibility Criteria:
Inclusion criteria:

* Female based on sex assigned at birth
* Preconception body mass index (BMI) 40.0 - 50 kg/m2
* Singleton pregnancy
* Age 18-44 years old
* \< = to 17 weeks gestational age
* Fluency in English to provide consent and complete study procedures
* Ability to provide informed consent
* Cleared by study doctor and the obstetrician/mid-wife provider to participate
* Access to a smartphone to complete intervention procedures

Exclusion criteria:

* Deemed medically high risk
* Multiple pregnancy (e.g., twins)
* Type 1 or 2 diabetes mellitus
* Early gestational diabetes (diagnosed at \< = to17 weeks gestational age through an oral glucose tolerance test)
* Currently eating ≤ 12 hours daily
* Autoimmune disorder (e.g., rheumatoid arthritis)
* iron deficiency anemia
* Inflammatory bowel disease
* Previous spontaneous preterm birth
* History of bariatric surgery
* Night shift work
* Currently incarcerated