Continuous glucose monitoring in obese pregnant women with no hyperglycemia on glucose tolerance test

The Impact of Overweight and Obesity on Pregnancy: A Narrative Review of Physiological Consequences, Risks and Challenges in Prenatal Care, and Early Intervention Strategies

BACKGROUND

While substantial literature exists on the intersection of overweight/obesity (OWO) and pregnancy, much of it focuses on specific aspects, making it difficult to maintain an overview of clinically relevant factors for optimal care of OWO women throughout pregnancy.

OBJECTIVES

To provide a comprehensive synthesis of the existing literature, covering the full spectrum of clinically relevant information needed to manage OWO women from preconception to birth.

METHODS

For this narrative review a literature search was conducted on PubMed in January 2025. Eligible studies included full-text English articles with data from human subjects, with no restrictions on publication date.

FINDINGS

The impact of OWO on pregnancy is multifaceted, encompassing four interrelated themes: physiological consequences, emerging risks, challenges in prenatal care, and intervention strategies. OWO women exhibit differences in metabolic and inflammatory pathways compared to normal-weight women, reflected in altered laboratory tests. When managing gestational diabetes and preeclampsia, obesity-related characteristics must be considered. Clinicians need to be alert of obesity-mediated fetal complications, including overgrowth, malformations, stillbirth, and preterm birth, while navigating challenges in ultrasound measurements. Interventions during the preconception and prenatal periods provide key opportunities to optimize maternal weight and reduce the risk of long-term disease development.

CONCLUSION

The review's insights enhance clinical practice and call on researchers and policymakers to prioritize strategies that offer early counseling for obese pregnant women. These initiatives aim to optimize outcomes for both mother and child and contribute to combating the global obesity crisis.

Continuous Glucose Monitor Metrics That Predict Neonatal Adiposity in Early and Later Pregnancy Are Higher in Obesity Despite Macronutrient-Controlled Eucaloric Diets

BACKGROUND

Fasting glucose is higher in pregnancies with obesity (OB); less is known about postprandial (PP) and nocturnal patterns when the diet is eucaloric and fixed or about the continuous-glucose-monitor (CGM) metrics that predict neonatal adiposity (NB%fat). We hypothesized that continuous glucose monitors (CGMs) would reveal higher glycemia in OB vs. normal weight (NW) during Early (14-16 weeks) and Later (26-28 weeks) gestation despite macronutrient-controlled eucaloric diets and elucidate unique predictors of NB%fat.

METHODS

In a prospective, parallel-group comparative study, a eucaloric diet (NW: 25 kcal/kg; OB: 30 kcal/kg) was provided (50% carbohydrate [20% simple/30% complex; of total calories], 35% fat, 15% protein) to Early and Later gestation groups wearing a blinded CGM for three days. CGM metrics (mean fasting; 1 h and 2 h PP; daytime and nocturnal glucose; percent time-in-range (%TIR: 63-140 mg/dL); PP excursions; and area-under-the-curve [AUC]) were interrogated between groups and as predictors of NB%fat by dual X-ray absorptiometry(DXA).

RESULTS

Fifty-four women with NW (BMI: 23 kg/m2; n = 27) and OB (BMI: 32; n = 27) provided their informed consent to participate. Early, the daytime glucose was higher in OB vs. NW (mean ± SEM) (91 ± 2 vs. 85 ± 2 mg/dL, p = 0.017), driven by 2 h PP glucose (95 ± 2 vs. 88 ± 2, p = 0.004). Later, those with OB exhibited higher nocturnal (89 ± 2 vs. 81 ± 2), daytime (95 ± 2 vs. 87 ± 2), 1 h (109 ± 3 vs. 98 ± 2), and 2 h PP (101 ± 3 vs. 92 ± 2) glucose (all p < 0.05) but no difference in %TIR (95-99%). Postprandial peak excursions for all meals were markedly blunted in both the Early (9-19 mg/dL) and Later (15-26 mg/dL). In OB, the Later group's 24 h AUC was correlated with NB%fat (r = 0.534, p = 0.02). Despite similar weight gain, infants of OB had higher birthweight (3528 ± 107 vs. 3258 ± 74 g, p = 0.037); differences in NB%fat did not reach statistical significance (11.0 vs. 8.9%; p > 0.05).

CONCLUSIONS

Despite macronutrient-controlled eucaloric diets, pregnancies with OB had higher glycemia Early and Later in gestation; the Later 24 h glucose AUC correlated with NB%fat. However, glycemic patterns were strikingly lower than current management targets.

Impact of pregestational obesity on perinatal complications: update in a Latin American cohort

OBJECTIVES

While the association between pregestational obesity and perinatal complications has been established, it is necessary to update the current understanding of its impact on maternal and foetal health due to its growing prevalence. Thus, this study aimed to investigate the association between pregestational obesity with the leading perinatal complications during the last 6 years.

STUDY DESIGN

A cross-sectional study was performed in San Felipe, Chile. Anonymised data of 11,197 deliveries that occurred between 2015 and 2021 were included.

METHODS

Pregestational body mass index was defined according to the World Health Organisation during the first trimester of pregnancy. The association between pregestational obesity and perinatal complications was analysed by calculating the odds ratio (OR), which was adjusted for confounding variables. Statistical differences were considered with a P-value of <0.05.

RESULTS

The prevalence of pregestational obesity was 30.1%. Pregestational obesity was related to a high incidence of perinatal complications (≥3 complications; P < 0.0001). The main perinatal complications were caesarean section, large for gestational age (LGA), gestational diabetes (GD), macrosomia, hypertensive disorders of pregnancy (HDP), premature rupture of membranes (PROM), intrauterine growth restriction, and failed induction. Pregestational obesity was shown to be a risk factor for macrosomia (OR: 2.3 [95% confidence interval {95% CI}: 2.0-2.8]), GD (OR: 1.9 [95% CI: 1.6-2.1]), HDP (OR: 1.8 [95% CI: 1.5-2.1]), LGA (OR: 1.6 [95% CI: 1.5-1.8]), failed induction (OR: 1.4 [95% CI: 1.0-1.8]), PROM (OR: 1.3 [95% CI: 1.1-1.6]), and caesarean section (OR: 1.3 [95% CI: 1.2-1.4]).

CONCLUSIONS

Pregestational obesity has been shown to be a critical risk factor for the main perinatal complications in the study population. Pregestational advice is imperative not only in preventing pregestational obesity but also in the mitigation of critical perinatal complications once they arise.

Obstetrical Outcome following Diagnosis of Gestational Diabetes in the Third Trimester (>29 Weeks) versus Second Trimester (24-28 Weeks): A Retrospective Comparative Study

OBJECTIVE

This study aimed to compare obstetrical outcomes between women diagnosed with gestational diabetes mellitus (GDM) in the third trimester after testing negative for GDM in two-step screening in the second trimester and women diagnosed in the second trimester.

STUDY DESIGN

This retrospective study compared obstetrical outcomes between 375 women diagnosed with GDM in the second trimester and 125 diagnosed in the third trimester.

RESULTS

Among women diagnosed with GDM in the third versus second trimester, the incidences were higher of morbid obesity (body mass index ≥35 kg/m2), macrosomia, and cesarean section (CS) due to suspected macrosomia: 23.2 versus 9.8%, p < 0.001; 44.0 versus 10.1%, p < 0.001; and 24.8 versus 6.3%, p < 0.001, respectively. For those diagnosed in the third versus second trimester, the incidences were lower of hypertensive disorders of pregnancy and intrauterine growth restriction, and a lower proportion of women needed pharmacological therapy for glucose control: 2.4 versus 9.0%, p = 0.016; 0.8 versus 8.2%, p < 0.001; and 12.0 versus 29.7%, p < 0.001, respectively. Multivariate analysis supported a correlation between third-trimester-diagnosed GDM and macrosomia, and between second-trimester-diagnosed GDM and hypertensive disorders of pregnancy.

CONCLUSION

Among women diagnosed with GDM in the third compared with the second trimester, the incidence of morbid obesity was higher; accordingly, the risks were higher for large for gestational age infants and delivery by CS, and lower for hypertensive disorders. Guidelines regarding repeat oral glucose tolerance testing in the third trimester should be considered following prospective studies.

KEY POINTS

· Third-trimester GDM was 29.9% among women with normal second-trimester screening.. · Morbid obesity and macrosomia were more frequent in third- versus second-trimester GDM.. · Incidence of preeclampsia was lower in third- versus second-trimester-diagnosed GDM..

Glucometabolic Alterations in Pregnant Women with Overweight or Obesity but without Gestational Diabetes Mellitus: An Observational Study

INTRODUCTION

Maternal overweight is a risk factor for gestational diabetes mellitus (GDM). However, emerging evidence suggests that an increased maternal body mass index (BMI) promotes the development of perinatal complications even in women who do not develop GDM. This study aims to assess physiological glucometabolic changes associated with increased BMI.

METHODS

Twenty-one women with overweight and 21 normal weight controls received a metabolic assessment at 13 weeks of gestation, including a 60-min frequently sampled intravenous glucose tolerance test. A further investigation was performed between 24 and 28 weeks in women who remained normal glucose tolerant.

RESULTS

At baseline, mothers with overweight showed impaired insulin action, whereby the calculated insulin sensitivity index (CSI) was lower as compared to normal weight controls (3.5 vs. 6.7 10-4 min-1 [microU/mL]-1, p = 0.025). After excluding women who developed GDM, mothers with overweight showed higher average glucose during the oral glucose tolerance test (OGTT) at the third trimester. Moreover, early pregnancy insulin resistance and secretion were associated with increased placental weight in normal glucose-tolerant women.

CONCLUSION

Mothers with overweight or obesity show an unfavorable metabolic environment already at the early stage of pregnancy, possibly associated with perinatal complications in women who remain normal glucose tolerant.

Obesity Is Associated With Higher Risk of Adverse Maternal and Neonatal Outcomes Than Supervised Gestational Diabetes

BACKGROUND

Unlike gestational diabetic mellitus (GDM), which is strictly managed by most patients and physicians, obesity does not have proper management guidelines, and the importance of its management during pregnancy is often ignored. The aim of this study was to compare maternal and neonatal outcomes according to obesity and GDM, alone or in combination.

METHODS

This was a retrospective cohort study of 3,078 consecutive pregnant women who experienced prenatal care and delivery of a live singleton neonate between January 2016 and December 2020 at our institution. Study participants were categorized into 4 mutually exclusive groups, as follows: group 1, no GDM without obesity; group 2, GDM without obesity; group 3, no GDM with obesity; and group 4, GDM with obesity.

RESULTS

Compared to group 2, group 3 had higher rates of pre-eclampsia, cesarean section including emergent cesarean section rate. Also, neonates in group 3 were heavier and had lower glucose levels compared to those in group 2. Of note, there was no significant difference in maternal or neonatal outcomes except the rate of large-for-gestational-age (LGA) between group 1 and group 2. Among the GDM groups, group 4 had higher risks for pre-eclampsia, cesarean section, and LGA infant status than group 2.

CONCLUSION

Our data showed that obese women without GDM face higher risk of adverse pregnancy outcomes than women with supervised GDM and non-obese women. We also confirmed that adverse pregnancy outcomes associated with GDM were mainly attributable to obesity among women receiving GDM education.