Different intensities of glycaemic control for women with gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) has major short- and long-term implications for both the mother and her baby. GDM is defined as a carbohydrate intolerance resulting in hyperglycaemia or any degree of glucose intolerance with onset or first recognition during pregnancy from 24 weeks' gestation onwards and which resolves following the birth of the baby. Rates for GDM can be as high as 25% depending on the population and diagnostic criteria used, and overall rates are increasing globally. There is wide variation internationally in glycaemic treatment target recommendations for women with GDM that are based on consensus rather than high-quality trials.

OBJECTIVES

To assess the effect of different intensities of glycaemic control in pregnant women with GDM on maternal and infant health outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (26 September 2022), and reference lists of the retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), cluster-RCTs, and quasi-RCTs. Trials were eligible for inclusion if women were diagnosed with GDM during pregnancy and the trial compared tighter and less-tight glycaemic targets during management. We defined tighter glycaemic targets as lower numerical glycaemic concentrations, and less-tight glycaemic targets as higher numerical glycaemic concentrations.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for carrying out data collection, assessing risk of bias, and analysing results. Two review authors independently assessed trial eligibility for inclusion, evaluated risk of bias, and extracted data for the four included studies. We assessed the certainty of evidence for selected outcomes using the GRADE approach. Primary maternal outcomes included hypertensive disorders of pregnancy and subsequent development of type 2 diabetes. Primary infant outcomes included perinatal mortality, large-for-gestational-age, composite of mortality or serious morbidity, and neurosensory disability.

MAIN RESULTS

This was an update of a previous review completed in 2016. We included four RCTs (reporting on 1731 women) that compared a tighter glycaemic control with less-tight glycaemic control in women diagnosed with GDM. Three studies were parallel RCTs, and one study was a stepped-wedged cluster-RCT. The trials took place in Canada, New Zealand, Russia, and the USA. We judged the overall risk of bias to be unclear. Two trials were only published in abstract form. Tight glycaemic targets used in the trials ranged between ≤ 5.0 and 5.1 mmol/L for fasting plasma glucose and ≤ 6.7 and 7.4 mmol/L postprandial. Less-tight targets for glycaemic control used in the included trials ranged between < 5.3 and 5.8 mmol/L for fasting plasma glucose and < 7.8 and 8.0 mmol/L postprandial. For the maternal outcomes, compared with less-tight glycaemic control, the evidence suggests a possible increase in hypertensive disorders of pregnancy with tighter glycaemic control (risk ratio (RR) 1.16, 95% confidence interval (CI) 0.80 to 1.69, 2 trials, 1491 women; low certainty evidence); however, the 95% CI is compatible with a wide range of effects that encompass both benefit and harm. Tighter glycaemic control likely results in little to no difference in caesarean section rates (RR 0.98, 95% CI 0.82 to 1.17, 3 studies, 1662 women; moderate certainty evidence) or induction of labour rates (RR 0.96, 95% CI 0.78 to 1.18, 1 study, 1096 women; moderate certainty evidence) compared with less-tight control. No data were reported for the outcomes of subsequent development of type 2 diabetes, perineal trauma, return to pre-pregnancy weight, and postnatal depression. For the infant outcomes, it was difficult to determine if there was a difference in perinatal mortality (RR not estimable, 2 studies, 1499 infants; low certainty evidence), and there was likely no difference in being large-for-gestational-age (RR 0.96, 95% CI 0.72 to 1.29, 3 studies, 1556 infants; moderate certainty evidence). The evidence suggests a possible reduction in the composite of mortality or serious morbidity with tighter glycaemic control (RR 0.84, 95% CI 0.55 to 1.29, 3 trials, 1559 infants; low certainty evidence); however, the 95% CI is compatible with a wide range of effects that encompass both benefit and harm. There is probably little difference between groups in infant hypoglycaemia (RR 0.92, 95% CI 0.72 to 1.18, 3 studies, 1556 infants; moderate certainty evidence). Tighter glycaemic control may not reduce adiposity in infants of women with GDM compared with less-tight control (mean difference -0.62%, 95% CI -3.23 to 1.99, 1 study, 60 infants; low certainty evidence), but the wide CI suggests significant uncertainty. We found no data for the long-term outcomes of diabetes or neurosensory disability. Women assigned to tighter glycaemic control experienced an increase in the use of pharmacological therapy compared with women assigned to less-tight glycaemic control (RR 1.37, 95% CI 1.17 to 1.59, 4 trials, 1718 women). Tighter glycaemic control reducedadherence with treatment compared with less-tight glycaemic control (RR 0.41, 95% CI 0.32 to 0.51, 1 trial, 395 women). Overall the certainty of evidence assessed using GRADE ranged from low to moderate, downgraded primarily due to risk of bias and imprecision.

AUTHORS' CONCLUSIONS

This review is based on four trials (1731 women) with an overall unclear risk of bias. The trials provided data on most primary outcomes and suggest that tighter glycaemic control may increase the risk of hypertensive disorders of pregnancy. The risk of birth of a large-for-gestational-age infant and perinatal mortality may be similar between groups, and tighter glycaemic targets may result in a possible reduction in composite of death or severe infant morbidity. However, the CIs for these outcomes are wide, suggesting both benefit and harm. There remains limited evidence regarding the benefit of different glycaemic targets for women with GDM to minimise adverse effects on maternal and infant health. Glycaemic target recommendations from international professional organisations vary widely and are currently reliant on consensus given the lack of high-certainty evidence. Further high-quality trials are needed, and these should assess both short- and long-term health outcomes for women and their babies; include women's experiences; and assess health services costs in order to confirm the current findings. Two trials are ongoing.

Histomorphological changes of the placenta and umbilical cord in pregnancies complicated by gestational diabetes mellitus

INTRODUCTION

The objective of this study was to compare the histomorphological changes of placenta and umbilical cord (UC), between gestational diabetes mellitus (GDM) and non- GDM pregnancies.

METHODS

In this prospective study, 222 parturients were recruited (117 GDM and 105 non-GDM). GDM was confirmed at 24-28 weeks of gestation, using one-step strategy. A full record of demographic, laboratory, histologic and gross morphology data of placenta and UC was extracted and analyzed.

RESULTS

Overall, 222 placentas/UCs met inclusion criteria. The mean (SD) of gestational age of GDM diagnosis was 20.68 (10.02) and the GDM duration was 16.76 (8.98) weeks. The mean HbA1C was 6.03 (0.41) % in the GDM group. The gross morphology findings including UC diameter and thick edematous UC differed significantly between two groups and more presented in GDM group, 1.41 (0.03) vs. 1.28 (0.03) centimeters; p-value = 0.006 and 34.19% vs. 16.19%; p-value = 0.002, respectively. The umbilical coiling index (UCI) was similar in two groups (p-value = 0.61). In the histological evaluation, persistence of central vessels differed significantly between two groups, more detected in non-GDM (47.62% vs. 32.97%; p-value = 0.04). No other significant histomorphological changes were detected between two groups.

DISCUSSION

This study showed that gross morphologic features such as UC diameter increment and thick edematous UC happened more frequently, among the GDM parturients. Due to early diagnosis, diagnosis strategy, and optimal glycemic control, the histomorphological changes were less in GDM comparing of non-GDM group.

Prediction of postnatal abnormal coiling of the umbilical cord in gestational diabetes mellitus: a diagnostic accuracy study

Objective: To investigate whether evaluations of antenatal umbilical coiling index (aUCI) could predict postnatal umbilical coiling index (UCI) (pUCI) in people with gestational diabetes mellitus (GDM) compared with normal pregnancy independent of maternal demographic and reproductive characteristics.Method: In this prospective study, 105 women with normal pregnancy, and 117 women with pregnancy complicated by GDM were recruited. Ultrasound scan of umbilical cord was performed at 18-23 and 37-41 weeks of gestation (WG). Evaluation of pUCI, as the reference standard, was performed within 24 hours after delivery.Findings: There was no significant relationship between aUCI and maternal demographic and reproductive characteristics. The mean for pUCI was 0.21 ± 0.12 in the GDM group, and 0.21 ± 0.09 in the normal pregnancy (p = .61). In the GDM group, a significant association was found between aUCI and pUCI categories (p = .004). The area under curve (AUC) was less than 0.5 for hypocoiling in both groups. For hypercoiling it was 0.84 ± 0.04 in the GDM group and 0.75 ± 0.06 in the normal pregnancy group (18-23 WG). In the GDM group the cutoff points that predict hypercoiling were 0.28 (18-23WG), and 0.21 (37-41WG). These were 0.35 (18-23WG), and 0.33 (37-41WG) in the normal pregnancy group. Diagnostic accuracy analysis revealed that in the GDM group, the sensitivity and specificity of hypercoiling for prediction of pUCI were 0.94 and 0.70 respectively at 18-23 WG.Conclusions: Antenatal hypercoiling at the second trimester of pregnancy strongly predict postnatal hypercoiling in pregnancies complicated by GDM.

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.

Different intensities of glycaemic control for women with gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) has major short- and long-term implications for both the mother and her baby. GDM is defined as a carbohydrate intolerance resulting in hyperglycaemia or any degree of glucose intolerance with onset or first recognition during pregnancy from 24 weeks' gestation onwards and which resolves following the birth of the baby. Rates for GDM can be as high as 25% depending on the population and diagnostic criteria used and rates are increasing globally. Risk factors associated with GDM include advanced maternal age, obesity, ethnicity, family history of diabetes, and a previous history of GDM, macrosomia or unexplained stillbirth. There is wide variation internationally in glycaemic treatment target recommendations for women with GDM that are based on consensus rather than high-quality trials.

OBJECTIVES

To assess the effect of different intensities of glycaemic control in pregnant women with GDM on maternal and infant health outcomes.

SEARCH METHODS

We searched the Cochrane Pregancy and Childbirth Group's Trials Register (31 January 2016), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (1 February 2016) and reference lists of the retrieved studies.

SELECTION CRITERIA

We included one randomised controlled trial. Cluster-randomised and quasi-randomised controlled trials were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We used the methods described in the Cochrane Handbook for Systematic Reviews of Interventions for carrying out data collection, assessing study quality and analysing results. Two review authors independently assessed trial eligibility for inclusion, evaluated methodological quality and extracted data for the one included study. We sought additional information from one trial author but had no response. We assessed the quality of evidence for selected outcomes using the GRADE approach.

MAIN RESULTS

We included one Canadian trial of 180 women, recruited between 20 to 32 weeks' gestation, who had been diagnosed with GDM. Data from 171 of the 180 women were published as a conference abstract and no full report has been identified. The overall risk of bias of the single included study was judged to be unclear.The included trial did not report on any of this review's primary outcomes. For the mother, these were hypertension disorders of pregnancy or subsequent development of type 2 diabetes. For the infant, our primary outcomes were (perinatal (fetal and neonatal) mortality; large-for-gestational age; composite of death or severe morbidity or later childhood neurosensory disability).The trial did report data relating to some of this review's secondary outcomes. There was no clear difference in caesarean section rates for women assigned to using strict glycaemic targets (pre-prandial 5.0 mmol/L (90 mg/L) and at one-hour postprandial 6.7 mmol/L (120 mg/dL)) (28/85, 33%) when compared with women assigned to using liberal glycaemic targets (pre-prandial 5.8 mmol/L (103 mg/dL) and at one-hour postprandial 7.8 mmol/L (140 mg/dL)) (21/86, 24%) (risk ratio (RR) 1.35, 95% confidence interval (CI) 0.83 to 2.18, one trial, 171 women; very low quality). Using the GRADE approach, we found the quality of the evidence to bevery low for caesarean section due to poor reporting of risk of bias, imprecision and publication bias. Strict glycaemic targets were associated with an increase in the use of pharmacological therapy (identified as the use of insulin in this study) (33/85; 39%) compared with liberal glycaemic targets (18/86; 21%) (RR 1.85, 95% CI 1.14 to 3.03; one trial, 171 women). CIs are wide suggesting imprecision and caution is required when interpreting the data. No other secondary maternal outcome data relevant to this review were reported. For the infant, there were no clear differences between the groups of women receiving strict and liberal glycaemic targets for macrosomia (birthweight greater than 4000 g) (RR 1.35, 95% CI 0.31 to 5.85, one trial, 171 babies); small-for-gestational age (RR 1.12, 95% CI 0.48 to 2.63, one trial, 171 babies); birthweight (mean difference (MD) -92.00 g, 95% CI -241.97 to 57.97, one trial, 171 babies) or gestational age (MD -0.30 weeks, 95% CI -0.73 to 0.13, one trial, 171 babies). Adverse effects data were not reported. No other secondary neonatal outcomes relevant to this review were reported.

AUTHORS' CONCLUSIONS

This review is based on a single study (involving 180 women) with an unclear risk of bias. The trial (which was only reported in a conference abstract) did not provide data for any of this review's primary outcomes but did provide data for a limited number of our secondary outcomes. There is insufficient evidence to guide clinical practice for targets for glycaemic control for women with GDM to minimise adverse effects on maternal and fetal health. Glycaemic target recommendations from international professional organisations for maternal glycaemic control vary widely and are reliant on consensus given the lack of high-quality evidence.Further high-quality trials are needed, and these should compare different glycaemic targets for guiding treatment of women with GDM, assess both short-term and long-term health outcomes for women and their babies, include women's experiences and assess health services costs. Four studies are ongoing.

The effects of mindfulness eating and yoga exercise on blood sugar levels of pregnant women with gestational diabetes mellitus

AIM

This randomized controlled trial was carried out to investigate the effect of mindfulness eating and yoga exercise on blood sugar levels among pregnant Thai women with GDM.

BACKGROUND

Interventions promoting achievement of good glycemic control result in desired pregnancy outcomes. Little is known about the health benefits of mindfulness eating and yoga exercise on blood sugar levels among pregnant with GDM.

METHODS

A randomized controlled trial was carried out. Main outcome measures were capillary fasting plasma glucose, 2-h postprandial blood glucose, and hemoglobin A1c.

RESULTS

The intervention group showed significantly reduced fasting plasma glucose, 2-h postprandial blood glucose, and glycosylated hemoglobin (HbA1c) in the intervention group (p<0.05).

CONCLUSIONS

Mindfulness eating and yoga exercise had health benefits on glycemic control in pregnant women with GDM. It should be recommended in clinical and community health services.

Gestational diabetes: comparision of the carpenter and the coustan thresholds with the new thresholds of Turkish women and implications of variations in diagnostic criteria

OBJECTIVE

To find optimal 100-g 3-h oral glucose tolerance test (OGTT) threshold levels for diagnosis of gestational diabetes (GDM) in Turkish pregnant women.

METHODS

This study was conducted with 808 women screened for GDM between 24-28 weeks of gestation using the 1-h 50-g glucose challenge test (GCT) with a subsequent 3-h 100-g OGTT for confirmation if screen was positive. The glucose values obtained were analysed by both the Carpenter and Coustan (C&C criteria) and National Diabetes Data Group (NDDG) criteria for the diagnosis of GDM and IGT. Optimal OGTT cutoff values for Turkish population were calculated by ROC curve analysis.

RESULTS

The new diagnostic criteria, based on the result of the 100-g OGTT obtained from the healthy pregnant women, were 82.5, 171.5, 151.5, and 111.5 mg/dl at 0, 1, 2, and 3 h. The prevalence of GDM was 15.7% by the new criteria, 8.1% by C&C criteria, and 5.6% by the NDDG criteria. According to new criteria, 7.7% of infants of diabetic mothers had macrosomia. This ratio was 2.6% for non diabetic women.

CONCLUSIONS

Ethnic differences, enviromental factors and nutritional habits may effect development of GDM. Application of some pre-determined nomograms to all races and ethnic groups can lead errors.