Impact of preconception weight loss on fasting glucose and pregnancy outcomes in women with obesity: A randomized trial

Teratogenic risks of treated and untreated maternal obesity

Untreated obesity in pregnancy is associated with adverse fetal and neonatal outcomes that influence the long-term offspring health trajectory, propagating obesity and cardiometabolic disease from one generation to the next. The current efforts to reduce the risk of these negative outcomes through preconception weight loss remain largely ineffective. Anti-obesity medications (AOMs) are an understudied option for this indication, likely due to the potential for teratogenicity with accidental exposure during pregnancy. However, the current recommendation to discontinue all AOMs prior to conception fails to frame obesity within the chronic disease paradigm typically used for preconception counseling. Evolving evidence suggests that glucagon-like peptide 1 receptor agonists (GLP-1 RAs), the newest and most effective AOM class, may be safe in early pregnancy. Although further research is needed, counseling about GLP-1 RAs during pregnancy should include the potential for both risk and benefit. This review summarizes the known risks that obesity in pregnancy poses to the offspring and discusses the benefits and limitations of current treatment strategies. While there remain several barriers to optimal preconception and prenatal care for people with obesity, this review aims to arm providers with the knowledge needed for patient-centered counseling prior to and during pregnancy.

Using continuous glucose monitoring (CGM) to understand glucose control in women with obesity during pregnancy

In women with obesity but without diabetes, the factors driving poor pregnancy outcomes are inadequately understood. This study explores glucose as a potential mediator of adverse pregnancy outcomes in women with obesity. A two-arm observational study was conducted in a single maternity hospital in Melbourne, Australia. Thirty-eight women without diabetes, 20 of normal weight (BMI 20-24.9 kg/m2) and 18 with obesity (BMI ≥30 kg/m2), wore a continuous glucose monitor and had anthropometry and blood samples collected in early, mid and late pregnancy. Subjects who developed gestational diabetes were excluded prior to analysis. Groups were compared with respect to patient-day mean glucose, mean blood glucose, daytime and nighttime glucose AUC, post-prandial glucose AUC, HOMA-IR and QUICKI. Five subjects developed gestational diabetes and were excluded from the analysis. Compared to controls (n = 19), women with obesity (n = 14) had significantly higher PDMG (p < .001), daytime and nighttime glucose AUC (p < .01) and post-breakfast glucose AUC (p < .001 and p = .043) and post-dinner glucose AUC (p < .001) in early and mid-pregnancy. Mean plasma glucose and post-lunch glucose AUC were only higher in women with obesity in early pregnancy (p = .009 and p < .001, respectively). In mid and late pregnancy, HOMA-IR was significantly higher (p < .05) and QUICKI (p < .01) significantly lower in the women with obesity compared to controls. Most parameters that used to assess glycaemic control in pregnancy demonstrated significantly higher plasma glucose in women with obesity compared to controls. This supports the hypothesis that glucose is a mediator of adverse pregnancy outcomes in women with obesity.

Predicting Pregnancy in Preconception Weight Loss Trials: Is it Possible?

Introduction

Predicting pregnancy is a challenge in preconception weight loss intervention trials. The current study examined whether self-reported pregnancy likelihood and timing were predictive of conception.

Methods

Adults (n = 184; 58% Hispanic; age = 33.4 ± 5.1; BMI = 33.6 ± 6.6) with overweight or obesity, prior gestational diabetes mellitus, and plans to become pregnant participated in a pre-conception behavioral weight loss intervention or control. At baseline, participants reported their estimated likelihood of pregnancy from 1 to 10 (categorized as low [1-3], medium [4-7], and high [8-10] likelihood); they also reported expected timeframe for pregnancy.

Results

Over the 4-year trial, 62 (30%) participants became pregnant. Participants who reported a high likelihood of pregnancy were more likely to conceive than those with a lower rating (45.7% vs. 21.1%). The sensitivity and specificity of a high likelihood rating predicting conception were 69%, 95% CI (56.2%, 80.1%), and 58%, 95% CI (48.9%, 67.0%), respectively. Among those who conceived, mean expected time to pregnancy was 21.6 ± 13.2 months while actual mean time was 11.3 ± 9.1 months. Baseline age, ethnicity, parity, BMI, income, and other demographics did not predict conception.

Conclusions

Pregnancy likelihood estimates best predicted conception, but sensitivity and specificity were low. Future work may consider additional ways to screen for likelihood of conception in preconception trials.

Improving dietary energy and antioxidative properties benefit early maternal BMI and further manage adverse pregnancy outcomes with better weight gain

Dietary characteristics affect maternal status in early pregnancy, which is important for later outcomes. However, Chinese dietary guidelines for pregnant women are not specific to obesity, overweight, and underweight. Moreover, since pregnancy is a prolonged process, an intermediate factor is needed to connect early maternal BMI with pregnancy outcomes. In this cohort of 1785 Chinese pregnant women from 2020 to 2022, 37.98% of participants had abnormal BMI in early pregnancy. A lower energy intake from carbohydrates (<50%) but higher intake from protein (>20%) and fat (>30%) resulted in excessive energy consumption, which was a risk factor for maternal obesity (adjusted OR (AOR): 1.49, 95%CI: 1.02-2.17) and overweight (AOR: 1.47, 95%CI: 1.00-2.18). Furthermore, the risk of maternal underweight was increased by a poor antioxidative diet (AOR: 2.80, 95%CI: 1.02-7.66) with a 20.28% lower intake of isoflavones and an imbalanced dietary structure (AOR: 3.95, 95%CI: 1.42-10.95) with less energy from fat (<20%) and unsaturated fatty acids (<3%). Following the timeline from gestation to delivery, early maternal obesity, overweight, and underweight increased the risk of abnormal body weight gain during pregnancy (AOR: 1.91-3.62, 95%CI: 1.20-6.12). Subsequently, abnormal weight gain further provoked adverse pregnancy outcomes, such as gestational diabetes mellitus, hypertensive disorders, cesarean section, and macrosomia (AOR, 1.33-2.58; 95%CI, 1.04-4.17). To minimize these threats, obese/overweight pregnant women in China might have more energy from carbohydrates (>65%) while reducing energy intake from protein (<10%) and fat (<20%). Meanwhile, underweight pregnant women are advised to increase their intake of dietary antioxidants (especially isoflavones) and consume more energy from fat (>30%) and unsaturated fatty acids (>11%). Finally, gestational body weight gain, as a potential intermediate bridge, should receive more attention.

Measuring Dietary Intake of Pregnant Women Post-Bariatric Surgery: Do Women Meet Recommendations?

Background: Bariatric surgery is increasingly offered to women of childbearing age and significantly reduces food intake and nutrient absorption. During pregnancy, associated risks, including micronutrient deficiency, are accentuated. This study describes maternal dietary intake and adherence to dietary recommendations in pregnant women with a history of bariatric surgery. Methods: Women aged 18-45 with singleton pregnancies post-bariatric surgery were recruited at <23 weeks of gestation and followed until birth. Dietary intake was measured using three non-consecutive 24 h recalls at enrolment and at 28 and 36 weeks using the standardized tool ASA24-Australia. Micronutrient supplementation dose and adherence was reported using the Brief Medication Adherence Questionnaire. Mean macronutrient intake was calculated from all diet recalls. Micronutrient intake was determined from diet recalls and from supplementation. Intake was compared to the recommended daily intakes for pregnancy. Results: Sixty-three women participated in the study. The participants met 65 ± 17.3% (mean ± SD) of estimated energy requirements, 53(23)% (median(IQR)) of fiber requirements, and exceeded fat and saturated fat recommendations. Dietary intake levels of iron, folate, zinc, calcium, and vitamin A were below recommended levels. Gastric bypass recipients consumed significantly less folate (p = 0.008), vitamin A (p = 0.035), and vitamin E (p = 0.027) than women post-gastric sleeve or gastric band. Multivitamins were used by 80% (n = 55) of participants at study enrolment, which increased their mean intake of all micronutrients to meet recommendations. Conclusions: Women who conceive post-bariatric surgery may require targeted support to meet the recommended nutrient intake. Micronutrient supplementation enables women to meet nutrient recommendations for pregnancy and is particularly important for gastric bypass recipients.

Prepregnancy and Gestational Interventions to Prevent Childhood Obesity

Childhood obesity is a significant global health issue with complex and multifactorial origins, often beginning before conception and influenced by both maternal and paternal health. The increased prevalence of prepregnancy obesity and gestational diabetes mellitus in women of reproductive age contributes to a heightened risk of metabolic dysfunction in offspring. Current clinical practices often implement lifestyle interventions after the first trimester and have limited success, implying that they miss a critical window for effective metabolic adjustments. This review examines the limitations of lifestyle interventions during pregnancy in improving perinatal outcomes and highlights the importance of initiating such interventions before conception to positively impact parental health and fetal development. A re-evaluation of strategies is needed to enhance the metabolic health of prospective parents as a preventive measure against childhood obesity.

Effectiveness of preconception weight loss interventions on fertility in women: a systematic review and meta-analysis

IMPORTANCE

Weight loss before conception is recommended for women with overweight or obesity to improve fertility outcomes, but evidence supporting this recommendation is mixed.

OBJECTIVE

To examine the effectiveness of weight loss interventions using lifestyle modification and/or medication in women with overweight or obesity on pregnancy, live birth, and miscarriage.

DATA SOURCES

An electronic search of MEDLINE, Embase, Cochrane Library, including Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature was conducted through July 6, 2022, via Wiley.

STUDY SELECTION AND SYNTHESIS

Randomized controlled trials examining weight loss interventions through lifestyle and/or medication in women with overweight or obesity planning pregnancy were included. Random-effects meta-analysis was conducted, reporting the risk ratio (RR) for each outcome. Subgroup analyses were conducted by intervention type, type of control group, fertility treatment, intervention length, and body mass index (BMI).

MAIN OUTCOME(S)

Clinical pregnancy, live birth, and miscarriage events.

RESULT(S)

A narrative review and meta-analysis were possible for 16 studies for pregnancy (n = 3,588), 13 for live birth (n = 3,329), and 11 for miscarriage (n = 3,248). Women randomized and exposed to a weight loss intervention were more likely to become pregnant (RR = 1.24, 95% CI 1.07-1.44; I2 = 59%) but not to have live birth (RR = 1.19, 95% CI 0.97-1.45; I2 = 69%) or miscarriage (RR = 1.17, 95% CI 0.79-1.74; I2 = 31%) compared with women in control groups. Subgroup analyses revealed women randomized to weight loss interventions lasting 12 weeks or fewer (n = 9, RR = 1.43; 95% CI 1.13-1.83) and women with a BMI ≥ 35 kg/m2 (n = 7, RR = 1.54; 95% CI, 1.18-2.02) were more likely to become pregnant compared with women in the control groups. Miscarriage was higher in intervention groups who underwent fertility treatment (n = 8, RR 1.45; 95% CI 1.07-1.96).

CONCLUSION(S)

Pregnancy rates were higher in women undergoing preconception weight loss interventions with no impact on live birth or miscarriage rates. Findings do not support one-size-fits-all recommendation for weight loss through lifestyle modification and/or medication in women with overweight or obesity immediately before conception to improve live birth or miscarriage outcomes.

Prepregnancy weight loss and maternal metabolic and inflammatory biomarkers during pregnancy: An analysis of National Health and Nutrition Examination Survey

AIM

Women with overweight or obesity are recommended to lose weight before conception to optimize pregnancy outcomes. However, the obstetrical implications of prepregnancy weight loss have been minimally examined. The objective of this study was to investigate the association between prepregnancy weight loss and maternal metabolic and inflammatory profiles during a subsequent pregnancy.

METHODS

This study was a retrospective analysis of National Health and Nutrition Examination Survey data (2003-2018). Participants were women who were pregnant at the time of assessment. Prepregnancy weight loss was described as percent weight change based on self-reported baseline (1 year before pregnancy) and prepregnancy weight. Metabolic (e.g., blood pressure [BP]) and inflammatory biomarkers (i.e., high-sensitivity C-reactive protein [hs-CRP]) were determined by standard medical tests. Statistical analyses included linear regressions with appropriate imputation, weighting, and variance estimation techniques.

RESULTS

Participants (N = 236) reported a mean percent weight loss of 4.6% (standard error [SE] = 0.3%) during the year before pregnancy. Regression models showed that prepregnancy weight loss was inversely associated with levels of total cholesterol (β = -1.24, p = 0.01), low-density lipoprotein-cholesterol (β = -0.79, p < 0.01), and high-density lipoprotein-cholesterol (β = -0.18, p < 0.01). The effect of prepregnancy weight loss on BP, insulin sensitivity, and hs-CRP was not significant, although there was a trend toward higher levels of diastolic BP (β = 0.24, p = 0.07) and hs-CRP (β = 0.10, p = 0.08).

CONCLUSIONS

This study found favorable changes in lipid profiles following prepregnancy weight loss. Due to limitations such as a relatively small sample size, self-reported weight measures, and missing data on several outcome variables, future studies are needed to confirm study findings.

Randomized controlled trial of prepregnancy lifestyle intervention to reduce recurrence of gestational diabetes mellitus

BACKGROUND

Preconception lifestyle intervention holds potential for reducing gestational diabetes mellitus, but clinical trial data are lacking.

OBJECTIVE

This study aimed to determine the effects of a prepregnancy weight loss intervention on gestational diabetes mellitus recurrence in women with overweight/obesity and previous gestational diabetes mellitus.

STUDY DESIGN

A 2-site, randomized controlled trial comparing a prepregnancy lifestyle intervention with educational control was conducted between December 2017 and February 2022. A total of 199 English- and Spanish-speaking adults with overweight/obesity and previous gestational diabetes mellitus were randomized to a 16-week prepregnancy lifestyle intervention with ongoing treatment until conception or educational control. The primary outcome was gestational diabetes mellitus recurrence. Analyses excluded 6 participants who conceived but did not have gestational diabetes mellitus ascertained by standard methods.

RESULTS

In the 63 (33%) women who conceived and had gestational diabetes mellitus ascertained (Ns=38/102 [37%] intervention vs 25/91 [28.0%] control; P=.17), those in the intervention group had significantly greater weight loss at 16 weeks compared with controls (4.8 [3.4-6.0] vs 0.7 [-0.9 to 2.3] kg; P=.001) and a greater proportion lost ≥5% of body weight (50.0% [17/34] vs 13.6% [3/22]; P=.005). There was no significant difference in the incidence of gestational diabetes mellitus recurrence between the intervention (57.9% [ns=23/38]) and the control group (44.0% [ns=11/25]; odds ratio, 1.8 [0.59-5.8]). Independent of group, greater prepregnancy weight loss predicted 21% lower odds of gestational diabetes mellitus recurrence (odds ratio, 0.79 [0.66-0.94]; P=.008). A ≥5% weight loss before conception reduced the odds of gestational diabetes mellitus recurrence by 82% (odds ratio, 0.18 [0.04-0.88]; P=.03).

CONCLUSION

Lifestyle intervention produced considerable prepregnancy weight loss but did not affect gestational diabetes mellitus rates. Given that the conception rate was 50% lower than expected, this study was underpowered.

A Women's health perspective on managing obesity

While the prevalence of obesity in US men and women is nearly equivalent, obesity management in women requires a different approach that considers age and life stage in development including sexual maturation/reproduction, menopause and post-menopause. In this review, the diagnosis and treatment of obesity using lifestyle modification, pharmacotherapy and metabolic and bariatric surgery are discussed from a women's health perspective, with emphasis on management during pregnancy and post-partum.

Maternal BMI in the preconception period, and association with child zBMI growth rates

BACKGROUND

Elevated body mass index (BMI) and rapid growth in early childhood are important predictors of obesity risk. The association between maternal preconception BMI and child growth rates is unclear.

OBJECTIVES

To assess the association between measured maternal preconception BMI and child age- and sex- standardized WHO BMI z-score (zBMI) growth rates and mean zBMI, in children aged 0-10 years old.

METHODS

A longitudinal cohort study was conducted with children (n = 499) enrolled in The Applied Research Group for Kids (TARGet Kids!) primary care practice-based research cohort. Maternal BMI was measured during the preconception period, defined as the 2 years prior to pregnancy. Repeated measures of child weight and height were obtained between 0 and 10 years of age. Linear mixed models were used to evaluate the association between maternal BMI and child zBMI growth rates and mean zBMI.

RESULTS

Maternal preconception BMI was associated with child zBMI growth rate during some growth periods, with the strongest association from age 0 to 4 months; a 5 kg/m2 higher maternal BMI was associated with 0.031 zBMI SD unit/mo higher growth rate (p = 0.004), and 0.186 SD unit higher mean child zBMI (p = 0.0002).

CONCLUSIONS

Maternal preconception BMI was associated with growth rate and mean zBMI in early childhood. The preconception period may be an important target for health interventions to promote healthy child growth rate and weight outcomes.

Using a Very Low Energy Diet to Achieve Substantial Preconception Weight Loss in Women with Obesity: A Review of the Safety and Efficacy

Obesity in women of reproductive age is common. Emerging evidence suggests that maternal obesity not only increases the risk of adverse pregnancy outcomes but also has an enduring impact on the metabolic health of the offspring. Given this, management of obesity prior to pregnancy is critically important. Almost all international guidelines suggest that women with obesity should aim to achieve weight loss prior to pregnancy. However, current pre-conception weight loss therapies are sub-optimal. Lifestyle modification typically results in modest weight loss. This may assist fertility but does not alter pregnancy outcomes. Bariatric surgery results in substantial weight loss, which improves pregnancy outcomes for the mother but may be harmful to the offspring. Alternative approaches to the management of obesity in women planning pregnancy are needed. Very low energy diets (VLEDs) have been proposed as a possible tool to assist women with obesity achieve weight loss prior to conception. While VLEDs can induce substantial and rapid weight loss, there are concerns about the impact of rapid weight loss on maternal nutrition prior to pregnancy and about inadvertent exposure of the early fetus to ketosis. The purpose of this review is to examine the existing literature regarding the safety and efficacy of a preconception VLED program as a tool to achieve substantial weight loss in women with obesity.

Weight gain during pregnancy: A narrative review on the recent evidences

Gestational weight gain is necessary for the normal fetus development, in fact a series of studies have evidenced that both low and excessive gestational weight gain is associated with negative fetal-neonatal outcomes. So, evidences on the optimal gestational weight gain across the ranges of the pre-pregnancy maternal body mass index are necessary. In this context, while for normal weight and underweight the recommendations of IOM are clearly stated and supported by well designed and conducted clinical studies, those for the obese pregnant women are even today debated. Pre-pregnancy obesity is associated with high risk to develop hypertension, gestational diabetes, cesarean section and high birth weight. The Institute of Medicine guidelines, in 2009, recommended that women with obesity gain 11-20 lb at a rate of 0.5 lb/week during the second and third trimesters of pregnancy. Successively, taking into account a series of meta-analysis, the American College of Obstetricians and Gynecologists emphasized that the IOM weight gain targets for obese pregnant women are too high. However the high risk to have babies small for gestational age, related to a low weight gain or a losing of weight during pregnancy, has also been demonstrated. More recent studies have taken into consideration the maternal and fetal outcomes of obese pregnant women with different obesity class (I,II,III) and different weight gain during pregnancy. The analysis of these studies, discussed in this narrative review, show that the appropriate gestational weight gain should be personalized considering the three obesity class; furthermore both an upper and lower limit of gestational weight gain should be reconsidered in order to prevent the negative maternal and fetal outcomes in these women.