Food glycemic index changes in overweight/obese pregnant women enrolled in a lifestyle program: a randomized controlled trial

Systematic review of interventions in early pregnancy among pregnant individuals at risk for hyperglycemia

OBJECTIVE

The maternal metabolic environment in early pregnancy can influence fetal growth trajectories. Our objective was to identify interventions initiated in early pregnancy (<20 weeks gestation) in pregnant individuals with risk factors for hyperglycemia and report their impact on primary (neonatal adiposity, small for gestational age, large for gestational age, macrosomia) and secondary outcomes (gestational weight gain, maternal hypertensive disorder, birth injury, NICU admission, preterm delivery, emergency cesarean section).

DATA SOURCES

We searched Cochrane Central database, Medline, Embase, CINAHL databases, and clinicaltrials.gov (September 2024) for clinical trials published between 2009 and 2024. Search terms included the key words "early OR during" OR "first trimester OR second trimester" AND "gestation OR pregnancy" OR "prenatal care" AND "insulin resistance" OR "metabolic health" OR "diabet*" OR "body composition" OR "obes*" OR "weight gain" OR "gestational diabetes" OR "hyperglycemia" OR "metabolic syndrome" AND "clinical trial."

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials (RCTs) and other trials reporting interventions initiated before 20 weeks gestation in participants with singleton pregnancies at risk for hyperglycemia (overweight and/or obesity, history of type 2 diabetes, and/or history of GDM) that reported at least one primary outcome were included. Studies had to be conducted with humans in high income countries as defined by the World Bank, written in English.

STUDY APPRAISAL AND SYNTHESIS METHODS

We used the Downs and Black checklist to evaluate the methodological quality and risk. Data was extracted independently and any questions were resolved through group discussion. Interventions were categorized and synthesized by type.

RESULTS

21,924 records were identified and 70 full-text articles met inclusion criteria. 65 articles were RCTs. Eight intervention categories were identified: diet only, physical activity or exercise only, diet and physical activity or exercise combined, lifestyle counseling, supplements, pharmaceuticals, early GDM screening, and mixed interventions. Only 12 studies reported statistically significant effects on primary neonatal outcomes.

CONCLUSIONS

Interventions initiated in early pregnancy (<20 weeks) among pregnant individuals at risk for hyperglycemia that include one or more of the following strategies can reduce risk of excess neonatal adiposity, macrosomia, large for gestational age and small for gestational age neonates: goal-setting and motivational strategies to improve diet and increase physical activity through individual and group sessions; lifestyle coaching that included behavioral techniques designed to empower participants by fostering autonomy in a supportive environment; structured group exercise classes three times per week; and personalized dietary recommendations. El resumen está disponible en Español al final del artículo.

Investigating discrepancies in findings between rigorous randomized trials and meta-analyses evaluating pregnancy interventions to limit gestational weight gain

INTRODUCTION

Robust randomized trials consistently demonstrate little impact from diet and physical activity interventions on gestational weight gain (GWG) and clinical outcomes, although meta-analyses report some benefit. Our aim was to evaluate the effect of trial quality on treatment effect estimates and review conclusions.

METHODS

We conducted a systematic review of dietary and/or physical activity interventions for pregnant women with a body mass index ≥18.5 kg/m2. We assessed studies for risk of bias and methodological features impacting reliability. Outcomes included GWG; gestational diabetes mellitus (GDM); pre-eclampsia; caesarean birth; and birth weight measures. For each outcome, a sequence of meta-analyses was performed based on intervention group and level of potential bias in the effect estimate.

RESULTS

We identified 128 eligible studies. The most robust estimate from a combined diet and physical activity behavioral intervention, with only studies at negligible risk of bias, was a difference in GWG of 1.10 kg (95% CI -1.62 to -0.58; 17,755 women). There was no evidence of an effect on any clinical outcomes.

CONCLUSIONS

Our findings highlight discrepancies produced by the indiscriminate inclusion of studies with methodological flaws in previous systematic reviews. Regular weighing of pregnant women is futile in the absence of clinical benefit.

Number and quality of randomized controlled trials in obstetrics published in the top general medical and obstetrics and gynecology journals

BACKGROUND

There has been an increasing number of randomized controlled trials published in obstetrics and maternal-fetal medicine to reduce biases of treatment effect and to provide insights on the cause-effect of the relationship between treatment and outcomes.

OBJECTIVE

This study aimed to identify obstetrical randomized controlled trials published in top weekly general medical journals and monthly obstetrics and gynecology journals, to assess their quality in reporting and identify factors associated with publication in different journals.

STUDY DESIGN

The 4 weekly medical journals with the highest 2019 impact factor (New England Journal of Medicine, The Lancet, The Journal of the American Medical Association, and British Medical Journal), the top 4 monthly obstetrics and gynecology journals with obstetrics-related research (American Journal of Obstetrics & Gynecology, Ultrasound in Obstetrics & Gynecology, Obstetrics & Gynecology, and the British Journal of Obstetrics and Gynaecology), and the American Journal of Obstetrics & Gynecology Maternal-Fetal Medicine were searched for obstetrical randomized controlled trials in the years 2018 to 2020. The primary outcome was the number of obstetrical randomized controlled trials published in the obstetrics and gynecology journals vs the weekly medical journals and the percentage of trials published, overall and per journal. The secondary outcomes included the proportion of positive vs negative trials overall and per journal and the assessment of the study characteristics of published trials, including quality assessment criteria.

RESULTS

Of the 4024 original research articles published in the 9 journals during the 3-year study period, 1221 (30.3%) were randomized controlled trials, with 137 (11.2%) randomized controlled trials being in obstetrics (46 in 2018, 47 in 2019, and 44 studies in 2020). Furthermore, 33 (24.1%) were published in weekly medical journals, and 104 (75.9%) were published in obstetrics and gynecology journals. The percentage of obstetrical randomized controlled trials published ranged from 1.5% to 9.6% per journal. Overall, 34.3% of obstetrical trials were statistically significant or "positive" for the primary outcome. Notably, 24.8% of the trials were retrospectively registered after the enrollment of the first study patient. Trials published in the 4 weekly medical journals enrolled significantly more patients (1801 vs 180; P<.001), received more often funding from the federal government (78.8% vs 35.6%; P<.001), and were more likely to be multicenter (90.9% vs 42.3%; P<.001), non-United States based (69.7% vs 49.0%; P=.03), and double blinded (45.5% vs 18.3%; P=.003) than trials published in the obstetrics and gynecology journals. There was no difference in study type (noninferiority vs superiority) and trial quality characteristics, including pretrial registration, ethics approval statement, informed consent statement, and adherence to the Consolidated Standards of Reporting Trials guidelines statement between studies published in weekly medical journals and studies published in obstetrics and gynecology journals.

CONCLUSION

Approximately 45 trials in obstetrics are being published every year in the highest impact journals, with one-fourth being in the weekly medical journals and the remainder in the obstetrics and gynecology journals. Only about a third of published obstetrical trials are positive. Trials published in weekly medical journals are larger, more likely to be funded by the government, multicenter, international, and double blinded. Quality metrics are similar between weekly medical journals and obstetrics and gynecology journals.

Do Lifestyle Interventions in Pregnant Women with Overweight or Obesity Have an Effect on Neonatal Adiposity? A Systematic Review with Meta-Analysis

Excessive body fat at birth is a risk factor for the development of childhood obesity. The aim of the present systematic review with meta-analysis was to evaluate the effect of lifestyle interventions in pregnant women with overweight or obesity on neonatal adiposity. The PubMed, Embase, Web of Science, Scopus, and LILACS databases were used as information sources. Original articles from randomized clinical trials of lifestyle intervention studies on pregnant women with excessive body weight and the effect on neonatal adiposity were considered eligible. The risk of bias was assessed using Cochrane criteria. The meta-analysis was calculated using the inverse variance for continuous data expressed as mean difference (MD), using the random effect model with a 95% confidence interval (CI). The outcomes were submitted to the GRADE evaluation. Of 2877 studies, four were included in the qualitative and quantitative synthesis (n = 1494). All studies were conducted in developed countries, with three including pregnant women with overweight or obesity, and one only pregnant women with obesity. The interventions had no effect on neonatal adiposity [Heterogeneity = 56%, MD = −0.21, CI = (−0.92, 0.50)] with low confidence in the evidence, according to GRADE. Studies are needed in low- and medium-developed countries with different ethnic-racial populations. PROSPERO (CRD42020152489).

An update on the use of inositols in preventing gestational diabetes mellitus (GDM) and neural tube defects (NTDs)

INTRODUCTION

Obstetric history and maternal body composition and lifestyle may be associated with serious complications both for the mother, such as gestational diabetes mellitus (GDM), and for the fetus, including congenital malformations such as neural tube defects (NTDs).

AREAS COVERED

In view of the recent knowledge, changes in nutritional and physical activity habits ameliorate glycemic control during pregnancy and in turn improve maternal and neonatal health outcomes. Recently, a series of small clinical and experimental studies indicated that supplemenation with inositols, a family of insulin sensitizers, was associated with beneficial impact for both GDM and NTDs.

EXPERT OPINION

Herein, we discuss the most significant scientific evidence supporting myo-inositol administration as a prophylaxis for the above-mentioned conditions.

The Impact of an Early Lifestyle Intervention on Pregnancy Outcomes in a Cohort of Insulin-Resistant Overweight and Obese Women

Obese women are more likely to have decreased insulin sensitivity and are at increased risk for many adverse pregnancy outcomes. An early lifestyle intervention (LI) may have the potential to reduce the impact of insulin resistance (IR) on perinatal outcomes. We report post hoc analysis of an open-label randomized control trial that includes IR women with body-mass index ≥25 randomly assigned to a LI with a customized low glycemic index diet or to standard care (SC) involving generic counseling about healthy diet and physical activity. Women were evaluated at 16, 20, 28, and 36 weeks of gestation, at which times perinatal outcomes were collected and analyzed. An oral-glucose-tolerance test (OGTT) showed that women in the LI group had lower plasma glucose levels at 120 min at 16-18 weeks of gestation, and at 60 and 120 min at 24-28 weeks. More importantly, these women had a lower rate of large-for-gestational-age (LGA) infants (p = 0.04). Interestingly, the caloric restriction and low-glycemic index diet did not increase the rate of small-for-gestational-age (SGA) babies in the LI group. A lifestyle intervention started early in pregnancy on overweight and obese women had the potential to restore adequate glucose tolerance and mitigate the detrimental role of IR on neonatal outcomes, especially on fetal growth.