Planned birth at or near term for improving health outcomes for pregnant women with gestational diabetes and their infants

Mediating processes underlying the associations between maternal obesity and the likelihood of cesarean birth

BACKGROUND

Pregnant women with obesity are more likely to experience cesarean birth compared to women without obesity. Yet, little is known about the underlying mechanisms. The objective of this study was therefore to evaluate how mediators contribute to the association between obesity and prelabor/intrapartum cesarean birth.

METHODS

We retrospectively analyzed Swiss cohort data from 394,812 singleton, cephalic deliveries between 2005 and 2020. Obesity (BMI ≥ 30 kg/m2 ) was defined as the exposure and prelabor or intrapartum cesarean birth as the outcomes. Hypothesized mediators included gestational comorbidities, large-for-gestational-age infant, pregnancy duration >410/7 weeks, slower labor progress, labor induction, and history of cesarean birth. We performed path analyses using generalized structural equation modeling and assessed mediation by a counterfactual approach.

RESULTS

Women with obesity had a cesarean birth rate of 39.36% vs. 24.12% in women without obesity. The path models mainly showed positive direct and indirect associations between obesity and cesarean birth. In the total sample, the mediation models explained up to 39.47% (95% CI 36.92-42.02) of the association between obesity and cesarean birth, and up to 57.13% (95% CI 54.10-60.16) when including history of cesarean birth as mediator in multiparous women. Slower labor progress and history of cesarean birth were found to be the most clinically significant mediators.

CONCLUSIONS

This study provides empirical insights into how obesity may increase cesarean birth rates through mediating processes. Particularly allowing for a slower labor progress in women with obesity might reduce cesarean birth rates and prevent subsequent repeat cesarean births in multiparous women.

Prediction of lung maturity through quantitative ultrasound analysis of fetal lung texture in women with diabetes during pregnancy

OBJECTIVES

The present study aimed to evaluate the performance of QuantusFLM® software, which performs quantitative ultrasound analysis of fetal lung texture, in predicting lung maturity in fetuses of diabetic mothers.

METHODS

The patients included in this study were between 34 and 38 weeks and 6 days gestation and were divided into two groups: (1) patients with diabetes on medication and (2) control. The ultrasound images were performed up to 48 h prior to delivery and analyzed using QuantusFLM® software, which classified each fetus as high or low risk for neonatal respiratory morbidity based on lung maturity or immaturity.

RESULTS

A total of 111 patients were included in the study, being 55 in diabetes and 56 in control group. The pregnant women with diabetes had significantly higher body mass index (27.8 kg/m2 vs. 25.9 kg/m2, respectively, p=0.02), increased birth weight (3,135 g vs. 2,887 g, respectively, p=0.002), and a higher rate of labor induction (63.6 vs. 30.4 %, respectively, p<0.001) compared to the control group. QuantusFLM® software was able to predict lung maturity in diabetes group with 96.4 % accuracy, 96.4 % sensitivity and 100 % positive predictive value. Considering the total number of patients, the software demonstrated accuracy, sensitivity, specificity, positive predictive value and negative predictive value of 95.5 , 97.2, 33.3, 98.1 and 25 %, respectively.

CONCLUSIONS

QuantusFLM® was an accurate method for predicting lung maturity in normal and DM singleton pregnancies and has the potential to aid in deciding the timing of delivery for pregnant women with DM.

Outcomes of Childbirth Education for Women With Pregnancy Complications

The purpose of this study was to examine associations between pregnancy outcomes and childbirth education, identifying any outcomes moderated by pregnancy complications. This was a secondary analysis of the Pregnancy Risk Assessment Monitoring System, Phase 8 data for four states. Logistic regression models compared outcomes with childbirth education for three subgroups: women with no pregnancy complications, women with gestational diabetes, and women with gestational hypertension. Women with pregnancy complications do not receive the same benefit from attending childbirth education as women with no pregnancy complications. Women with gestational diabetes who attended childbirth education were more likely to have a cesarean birth. The childbirth education curriculum may need to be altered to provide maximum benefits for women with pregnancy complications.

Risk of Stillbirth in Pregnancies Complicated by Diabetes, Stratified by Fetal Growth

OBJECTIVE

To compare stillbirth rates per week of expectant management stratified by birth weight in pregnancies complicated by gestational diabetes mellitus (GDM) or pregestational diabetes mellitus.

METHODS

A national population-based retrospective cohort study of singleton, nonanomalous pregnancies complicated by pregestational diabetes or GDM was performed using national birth and death certificate data from 2014 to 2017. Stillbirth rates per 10,000 patients (stillbirth incidence at gestational age week/ongoing pregnancies-[0.5×live births at gestational age week]) were determined for each week of pregnancy from 34 to 39 completed weeks of gestation. Pregnancies were stratified by birth weight, categorized as having small-for-gestational-age (SGA), appropriate-for-gestational-age (AGA), or large-for-gestational-age (LGA) fetuses, assigned by sex-based Fenton criteria. Relative risk (RR) and 95% CI for stillbirth were calculated for each gestational age week compared with the GDM-related AGA group.

RESULTS

We included 834,631 pregnancies complicated by either GDM (86.9%) or pregestational diabetes (13.1%) in the analysis, with a total of 3,033 stillbirths. Stillbirth rates increased with advancing gestational age for pregnancies complicated by both GDM and pregestational diabetes regardless of birth weight. Compared with pregnancies with AGA fetuses, those with both SGA and LGA fetuses were significantly associated with an increased risk of stillbirth at all gestational ages. Ongoing pregnancies at 37 weeks of gestation complicated by pregestational diabetes with LGA or SGA fetuses had respective stillbirth rates of 64.9 and 40.1 per 10,000 patients. Pregnancies complicated by pregestational diabetes had an RR of stillbirth of 21.8 (95% CI 17.4-27.2) for LGA fetuses and 13.5 (95% CI 8.5-21.2) for SGA fetuses compared with GDM-related AGA at 37 weeks of gestation. The greatest absolute risk of stillbirth was in pregnancies complicated by pregestational diabetes at 39 weeks of gestation with LGA fetuses (97/10,000).

CONCLUSION

Pregnancies complicated by both GDM and pregestational diabetes affected by pathologic fetal growth have an increased risk of stillbirth with advancing gestational age. This risk is significantly higher with pregestational diabetes, especially pregestational diabetes with LGA fetuses.

Pregnancy outcomes in women with gestational diabetes mellitus by models of care: a retrospective cohort study

OBJECTIVE

To compare birth outcomes of women with gestational diabetes mellitus (GDM) with background obstetric population, stratified by models of care.

DESIGN

Retrospective cohort study.

SETTING

A tertiary referral centre in Sydney, Australia.

PARTICIPANTS

All births 1 January 2018 to 30 November 2020. Births <24 weeks, multiple gestations and women with pre-existing diabetes were excluded.

METHODS

Data were obtained from electronic medical records. Women were classified according to GDM status and last clinic attended prior to delivery. Model of care included attendance at dedicated GDM obstetric clinics, and routine antenatal care.

MAIN OUTCOME MEASURES

Hypertensive disorders of pregnancy (HDP), pre-term birth (PTB), induction of labour (IOL), operative delivery, small for gestational age (SGA), large for gestational age, postpartum haemorrhage, obstetric anal sphincter injury (OASIS), neonatal hypoglycaemia, neonatal hypothermia, neonatal respiratory distress, neonatal intensive care unit (NICU) admission.

RESULTS

The GDM rate was 16.3%, with 34.0% of women managed in dedicated GDM clinics. Women with GDM had higher rates of several adverse outcomes. Only women with GDM attending non-dedicated clinics had increased odds of HDP (adjusted OR (adj OR) 1.6, 95% CI 1.2 to 2.0), PTB (adj OR 1.7, 95% CI 1.4 to 2.0), OASIS (adj OR 1.4, 95% CI 1.0 to 2.0), similar odds of induction (adj OR 1.0, 95% CI 0.9 to 1.1) compared with non-GDM women. There were increased odds of NICU admission (adj OR 1.5, 95% CI 1.3 to 1.8) similar to women attending high-risk GDM clinics.

CONCLUSIONS

Women with GDM receiving care in lower risk clinics had similar or higher rates of adverse outcomes. Pathways of care need to be similar in all women with GDM.

Timing of delivery in women with diabetes: A population-based study

Introduction

Women with diabetes, and their infants, have an increased risk of adverse events due to excess fetal growth. Earlier delivery, when fetuses are smaller, may reduce these risks. This study aimed to evaluate the week‐specific risks of maternal and neonatal morbidity/mortality to assist with obstetrical decision making.

Material and methods

In this population‐based cohort study, women with type 1 diabetes (n = 5889), type 2 diabetes (n = 9422) and gestational diabetes (n = 138 917) and a comparison group without diabetes (n = 2 553 243) who delivered a singleton infant at ≥36 completed weeks of gestation between 2004 and 2014 were identified from the Canadian Institute of Health Information Discharge Abstract Database. Multivariate logistic regression was used to determine the week‐specific rates of severe maternal and neonatal morbidity/mortality among women delivered iatrogenically vs those undergoing expectant management.

Results

For all women, the absolute risk of severe maternal morbidity/mortality was low, typically impacting less than 1% of women, and there was no significant difference in gestational age‐specific severe maternal morbidity/mortality between iatrogenic delivery and expectant management among women with any form of diabetes. Among women with gestational diabetes, iatrogenic delivery was associated with an increased risk of neonatal morbidity/mortality compared with expectant management at 36 and 37 weeks’ gestation (76.7 and 27.8 excess cases per 1000 deliveries, respectively) and a lower risk of neonatal morbidity/mortality at 38, 39 and 40 weeks’ gestation (7.9, 27.3 and 15.9 fewer cases per 1000 deliveries, respectively). Increased risks of severe neonatal morbidity following iatrogenic delivery compared with expectant management were also observed for women with type 1 diabetes at 36 (98.3 excess cases per 1000 deliveries) and 37 weeks’ gestation (44.5 excess cases per 1000 deliveries) and for women with type 2 diabetes at 36 weeks’ gestation (77.9 excess cases per 1000 deliveries) weeks.

Conclusions

The clinical decision regarding timing of delivery is complex and contingent on maternal‐fetal wellbeing, including adequate glycemic control. This study suggests that delivery at 38, 39 or 40 weeks’ gestation may optimize neonatal outcomes among women with diabetes.

Recent advances in the antepartum management of diabetes

Gestational and pre-gestational diabetes are frequent problems encountered in obstetrical practice and their complications may influence both the mother (such as hypertension, pre-eclampsia, increased caesarean rates) and the foetus (such as macrosomia, shoulder dystocia, respiratory distress, hypoglycaemia, or childhood obesity and diabetes). Given the important implications for mothers and their offspring, screening and appropriate management of diabetes during pregnancy are essential. This is a review of articles published between 2015 and 2018 on Medline via Ovid that focus on advances in the management of diabetes in pregnancy. Recent data have concentrated predominantly on optimising glycaemic control, which is key for minimising the burden of maternal and foetal complications. Lifestyle changes, notably physical exercise and diet adjustments, appear to have beneficial effects. However, data are inconclusive with respect to which diet and form of exercise provide optimal benefits. Oral glycaemic agents-in particular, metformin-are gaining acceptance as more data indicating their long-term safety for the foetus and newborn emerge. Recent reviews present inconclusive data on the efficacy and safety of insulin analogues. New technologies such as continuous insulin pumps for type 1 diabetes and telemedicine-guided management of diabetes are significantly appreciated by patients and represent promising clinical tools. There are few new data addressing the areas of antenatal foetal surveillance, the timing and need for induction of delivery, and the indications for planned caesarean section birth.

Treatments for women with gestational diabetes mellitus: an overview of Cochrane systematic reviews

BACKGROUND

Successful treatments for gestational diabetes mellitus (GDM) have the potential to improve health outcomes for women with GDM and their babies.

OBJECTIVES

To provide a comprehensive synthesis of evidence from Cochrane systematic reviews of the benefits and harms associated with interventions for treating GDM on women and their babies.

METHODS

We searched the Cochrane Database of Systematic Reviews (5 January 2018) for reviews of treatment/management for women with GDM. Reviews of pregnant women with pre-existing diabetes were excluded.Two overview authors independently assessed reviews for inclusion, quality (AMSTAR; ROBIS), quality of evidence (GRADE), and extracted data.

MAIN RESULTS

We included 14 reviews. Of these, 10 provided relevant high-quality and low-risk of bias data (AMSTAR and ROBIS) from 128 randomised controlled trials (RCTs), 27 comparisons, 17,984 women, 16,305 babies, and 1441 children. Evidence ranged from high- to very low-quality (GRADE). Only one effective intervention was found for treating women with GDM.EffectiveLifestyle versus usual careLifestyle intervention versus usual care probably reduces large-for-gestational age (risk ratio (RR) 0.60, 95% confidence interval (CI) 0.50 to 0.71; 6 RCTs, N = 2994; GRADE moderate-quality).PromisingNo evidence for any outcome for any comparison could be classified to this category.Ineffective or possibly harmful Lifestyle versus usual careLifestyle intervention versus usual care probably increases the risk of induction of labour (IOL) suggesting possible harm (average RR 1.20, 95% CI 0.99 to 1.46; 4 RCTs, N = 2699; GRADE moderate-quality).Exercise versus controlExercise intervention versus control for return to pre-pregnancy weight suggested ineffectiveness (body mass index, BMI) MD 0.11 kg/m², 95% CI -1.04 to 1.26; 3 RCTs, N = 254; GRADE moderate-quality).Insulin versus oral therapyInsulin intervention versus oral therapy probably increases the risk of IOL suggesting possible harm (RR 1.3, 95% CI 0.96 to 1.75; 3 RCTs, N = 348; GRADE moderate-quality).Probably ineffective or harmful interventionsInsulin versus oral therapyFor insulin compared to oral therapy there is probably an increased risk of the hypertensive disorders of pregnancy (RR 1.89, 95% CI 1.14 to 3.12; 4 RCTs, N = 1214; GRADE moderate-quality).InconclusiveLifestyle versus usual careThe evidence for childhood adiposity kg/m² (RR 0.91, 95% CI 0.75 to 1.11; 3 RCTs, N = 767; GRADE moderate-quality) and hypoglycaemia was inconclusive (average RR 0.99, 95% CI 0.65 to 1.52; 6 RCTs, N = 3000; GRADE moderate-quality).Exercise versus controlThe evidence for caesarean section (RR 0.86, 95% CI 0.63 to 1.16; 5 RCTs, N = 316; GRADE moderate quality) and perinatal death or serious morbidity composite was inconclusive (RR 0.56, 95% CI 0.12 to 2.61; 2 RCTs, N = 169; GRADE moderate-quality).Insulin versus oral therapyThe evidence for the following outcomes was inconclusive: pre-eclampsia (RR 1.14, 95% CI 0.86 to 1.52; 10 RCTs, N = 2060), caesarean section (RR 1.03, 95% CI 0.93 to 1.14; 17 RCTs, N = 1988), large-for-gestational age (average RR 1.01, 95% CI 0.76 to 1.35; 13 RCTs, N = 2352), and perinatal death or serious morbidity composite (RR 1.03; 95% CI 0.84 to 1.26; 2 RCTs, N = 760). GRADE assessment was moderate-quality for these outcomes.Insulin versus dietThe evidence for perinatal mortality was inconclusive (RR 0.74, 95% CI 0.41 to 1.33; 4 RCTs, N = 1137; GRADE moderate-quality).Insulin versus insulinThe evidence for insulin aspart versus lispro for risk of caesarean section was inconclusive (RR 1.00, 95% CI 0.91 to 1.09; 3 RCTs, N = 410; GRADE moderate quality).No conclusions possibleNo conclusions were possible for: lifestyle versus usual care (perineal trauma, postnatal depression, neonatal adiposity, number of antenatal visits/admissions); diet versus control (pre-eclampsia, caesarean section); myo-inositol versus placebo (hypoglycaemia); metformin versus glibenclamide (hypertensive disorders of pregnancy, pregnancy-induced hypertension, death or serious morbidity composite, insulin versus oral therapy (development of type 2 diabetes); intensive management versus routine care (IOL, large-for-gestational age); post- versus pre-prandial glucose monitoring (large-for-gestational age). The evidence ranged from moderate-, low- and very low-quality.

AUTHORS' CONCLUSIONS

Currently there is insufficient high-quality evidence about the effects on health outcomes of relevance for women with GDM and their babies for many of the comparisons in this overview comparing treatment interventions for women with GDM. Lifestyle changes (including as a minimum healthy eating, physical activity and self-monitoring of blood sugar levels) was the only intervention that showed possible health improvements for women and their babies. Lifestyle interventions may result in fewer babies being large. Conversely, in terms of harms, lifestyle interventions may also increase the number of inductions. Taking insulin was also associated with an increase in hypertensive disorders, when compared to oral therapy. There was very limited information on long-term health and health services costs. Further high-quality research is needed.

Planned birth at or near term for improving health outcomes for pregnant women with pre-existing diabetes and their infants

BACKGROUND

Pregnant women with pre-existing diabetes (Type 1 or Type 2) have increased rates of adverse maternal and neonatal outcomes. Current clinical guidelines support elective birth, at or near term, because of increased perinatal mortality during the third trimester of pregnancy.This review replaces a review previously published in 2001 that included "diabetic pregnant women", which has now been split into two reviews. This current review focuses on pregnant women with pre-existing diabetes (Type 1 or Type 2) and a sister review focuses on women with gestational diabetes.

OBJECTIVES

To assess the effect of planned birth (either by induction of labour or caesarean birth) at or near term gestation (37 to 40 weeks' gestation) compared with an expectant approach, for improving health outcomes for pregnant women with pre-existing diabetes and their infants. The primary outcomes relate to maternal and perinatal mortality and morbidity.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (15 August 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

We planned to include randomised trials (including those using a cluster-randomised design) and non-randomised trials (e.g. quasi-randomised trials using alternate allocation) which compared planned birth, at or near term, with an expectant approach for pregnant women with pre-existing diabetes.

DATA COLLECTION AND ANALYSIS

Two of the review authors independently assessed study eligibility. In future updates of this review, at least two of the review authors will extract data and assess the risk of bias in included studies. We will also assess the quality of the evidence using the GRADE approach.

MAIN RESULTS

We identified no eligible published trials for inclusion in this review.We did identify one randomised trial which examined whether expectant management reduced the incidence of caesarean birth in uncomplicated pregnancies of women with gestational diabetes (requiring insulin) and with pre-existing diabetes. However, published data from this trial does not differentiate between pre-existing and gestational diabetes, and therefore we excluded this trial.

AUTHORS' CONCLUSIONS

In the absence of evidence, we are unable to reach any conclusions about the health outcomes associated with planned birth, at or near term, compared with an expectant approach for pregnant women with pre-existing diabetes.This review demonstrates the urgent need for high-quality trials evaluating the effectiveness of planned birth at or near term gestation for pregnant women with pre-existing (Type 1 or Type 2) diabetes compared with an expectant approach.

Planned birth at or near term for improving health outcomes for pregnant women with gestational diabetes and their infants

BACKGROUND

Gestational diabetes is a type of diabetes that occurs during pregnancy. Women with gestational diabetes are more likely to experience adverse health outcomes such as pre-eclampsia or polyhydramnios (excess amniotic fluid). Their babies are also more likely to have health complications such as macrosomia (birthweight > 4000 g) and being large-for-gestational age (birthweight above the 90th percentile for gestational age). Current clinical guidelines support elective birth, at or near term in women with gestational diabetes to minimise perinatal complications, especially those related to macrosomia.This review replaces a review previously published in 2001 that included "diabetic pregnant women", which has now been split into two reviews. This current review focuses on pregnant women with gestational diabetes and a sister review focuses on women with pre-existing diabetes (Type 1 or Type 2).

OBJECTIVES

To assess the effect of planned birth (either by induction of labour or caesarean birth), at or near term (37 to 40 weeks' gestation) compared with an expectant approach for improving health outcomes for women with gestational diabetes and their infants. The primary outcomes relate to maternal and perinatal mortality and morbidity.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) (15 August 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised trials comparing planned birth, at or near term (37 to 40 weeks' gestation), with an expectant approach, for women with gestational diabetes. Cluster-randomised and non-randomised trials (e.g. quasi-randomised trials using alternate allocation) were also eligible for inclusion but none were identified.

DATA COLLECTION AND ANALYSIS

Two of the review authors independently assessed study eligibility, extracted data and assessed the risk of bias of the included study. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

The findings of this review are based on a single trial involving 425 women with gestational diabetes. The trial compared induction of labour with expectant management (waiting for the spontaneous onset of labour in the absence of any maternal or fetal issues that may necessitate birth) in pregnant women with gestational diabetes at term. We assessed the overall risk of bias as being low for most domains, apart from performance, detection and attrition bias (for outcome perineum intact), which we assessed as being at high risk. It was an open-label trial, and women and healthcare professionals were not blinded.There were no clear differences between women randomised to induction of labour and women randomised to expectant management for maternal mortality or serious maternal morbidity (risk ratio (RR) 1.48, 95% confidence interval (CI) 0.25 to 8.76, one trial, 425 women); caesarean section (RR 1.06, 95% CI 0.64 to 1.77, one trial, 425 women); or instrumental vaginal birth (RR 0.81, 95% CI 0.45 to 1.46, one trial, 425 women). For the primary outcome of maternal mortality or serious maternal morbidity, there were no deaths in either group and serious maternal morbidity related to admissions to intensive care unit. The quality of the evidence contributing to these outcomes was assessed as very low, mainly due to the study having high risk of bias for some domains and because of the imprecision of effect estimates.In relation to primary neonatal outcomes, there were no perinatal deaths in either group. The quality of evidence for this outcome was judged as very low, mainly due to high risk of bias and imprecision of effect estimates. There were no clear differences in infant outcomes between women randomised to induction of labour and women randomised to expectant management: shoulder dystocia (RR 2.96, 95% CI 0.31 to 28.21, one trial, 425 infants, very low-quality evidence); large-for-gestational age (RR 0.53, 95% CI 0.28 to 1.02, one trial, 425 infants, low-quality evidence).There were no clear differences between women randomised to induction of labour and women randomised to expectant management for postpartum haemorrhage (RR 1.17, 95% CI 0.53 to 2.54, one trial, 425 women); admission to intensive care unit (RR 1.48, 95% CI 0.25 to 8.76, one trial, 425 women); and intact perineum (RR 1.02, 95% CI 0.73 to 1.43, one trial, 425 women). No infant experienced a birth trauma, therefore, we could not draw conclusions about the effect of the intervention on the outcomes of brachial plexus injury and bone fracture at birth. Infants of women in the induction-of-labour group had higher incidences of neonatal hyperbilirubinaemia (jaundice) when compared to infants of women in the expectant-management group (RR 2.46, 95% CI 1.11 to 5.46, one trial, 425 women).We found no data on the following prespecified outcomes of this review: postnatal depression, maternal satisfaction, length of postnatal stay (mother), acidaemia, intracranial haemorrhage, hypoxia ischaemic encephalopathy, small-for-gestational age, length of postnatal stay (baby) and cost.The authors of this trial acknowledge that it is underpowered for their primary outcome of caesarean section. The authors of the trial and of this review note that the CIs demonstrate a wide range, therefore making it inappropriate to draw definite conclusions.

AUTHORS' CONCLUSIONS

There is limited evidence to inform implications for practice. The available data are not of high quality and lack power to detect possible important differences in either benefit or harm. There is an urgent need for high-quality trials evaluating the effectiveness of planned birth at or near term gestation for women with gestational diabetes compared with an expectant approach.