Research Background
Women with high body mass indices are urged to lose weight before becoming pregnant, but no studies have been done to determine how this affects health outcomes. The goal of the survey by LeBlanc et al. was to determine whether weight loss before pregnancy reduces gestational weight gain and improves pregnancy outcomes (2021). Between May 2015 and October 2019, a pragmatic randomized clinical trial was conducted at Kaiser Permanente Northwest, an integrated health system. The assignment of conditions was hidden from the data-gathering process.
Participants
Women aged 18-40 who planned to become pregnant within 2 years and had a body mass index of 27 kg/m2 were eligible to participate. Twenty-seven thousand six hundred sixty-five health system members who fit the age and BMI requirements received recruitment contacts; 329 women went to screening appointments, and 326 were randomly assigned to receive routine care or a behavioral weight loss intervention.
Hypotheses and Objectives
The intervention consisted of weekly phone consultations with a health coach for 6 months, followed by monthly meetings for 18 months or until the end of the pregnancy. The a priori primary hypothesis that intervention participants would be less likely to exceed advised limits for gestational weight gain overall and throughout each trimester was tested using logistic regression.
Secondary and exploratory aims included absolute weight gain before and during pregnancy, as well as perinatal and baby outcomes. 169 of the 326 individuals had 14-week singleton pregnancies. At the outset, the body mass index was 34.85 ± 8 kg/m2, and the mean age was 31.33 ± 5 years. Before becoming pregnant, intervention group members shed more weight than control group members.
Study Results
However, participants in the intervention group gained more weight overall during the second and third trimesters than those in the control group. However, at no time point did the frequencies of arms surpassing the recommended gestational weight increase range differ. The intervention group saw fewer spontaneous miscarriages than the control arm, but there were no additional variations in the secondary or exploratory outcomes.
Women’s risk of exceeding the recommended gestational weight gain was unaffected by their participation in the prenatal weight-loss strategy. Despite the intervention group’s successful weight loss before conception, it was associated with higher weight gain in the last trimester. Pre-pregnancy weight loss therapies may need to be paired with intensive weight control that lasts until delivery to reduce weight during pregnancy and enhance mother and child outcomes.
A high body mass index (BMI) before conception and excessive weight gain during pregnancy are linked to unfavorable pregnancy outcomes. Guidelines advise obese women to lose weight before getting pregnant to prevent excessive prenatal weight gain (GWG). However, research has not looked prospectively at how pre-pregnancy weight control influences GWG or delivery outcomes. Participants’ height and weight were assessed at a baseline visit while wearing light indoor clothing and without shoes; weight was determined using a routinely calibrated digital scale.
The intervention or control arm was then randomly assigned to the participants. Age, BMI, and parity were used to stratify the randomization. Until the randomization button was pushed, the allocation was hidden. Women in the intervention group attended an introductory session to review the website and the research objectives. Information about having a healthy pregnancy was presented to women in the control group; participants in the intervention group got this information in later sessions. Every woman received regular prenatal care from their obstetrician. The research team sent birthday and holiday cards yearly to help with retention.
The plan included access to a personalized intervention website and specialized 20–30-minute telephone counseling sessions with the health coach, a licensed behavioral interventionist. It was created to be implemented in a wide range of contexts. Sessions took place once a week for six months, then once a month for 18 months, or until the conclusion of the pregnancy.
The Harris-Benedict equation created a customized calorie target for each participant to help them lose weight before becoming pregnant. They were also urged to exercise, setting two daily goals: 60 minutes of moderate-intensity physical activity and at least 10,000 steps. A participant who disclosed becoming pregnant remained to participate in the intervention, but the main objective shifted to maintaining GWG within NAM standards. They also made changes to their diet and caloric goals.
In prespecified stratified analyses, participants in the intervention group lost significantly more weight before pregnancy among those who became pregnant within six months and between 6 and 24 months following randomization. There was no difference in weight change before pregnancy between the intervention and control arms among women who became pregnant after the intervention. The likelihood of women exceeding NAM GWG requirements did not differ significantly between those who participated in a successful behavioral weight-loss program before becoming pregnant and those who received standard medical care.
Participants in the intervention group, particularly those in the maintenance stage of pregnancy, gained significantly more weight than participants in the control group in the second half of the pregnancy. By the end of the pregnancy, it was impossible to tell them apart from the controls. Although the Prepare intervention caused prenatal weight loss, which may have enhanced the early intrauterine environment, it also had the unanticipated side effect of increasing GWG in subsequent pregnancies. Early-pregnancy weight-loss initiatives may need to be paired with active weight-management strategies that continue through delivery.
Reference
LeBlanc, E. S., Smith, N. X., Vesco, K. K., Paul, I. M., & Stevens, V. J. (2021). Weight loss prior to pregnancy and subsequent gestational weight gain: prepare, a randomized clinical trial. American journal of obstetrics and gynecology, 224(1), 99-e1.