Glucose targets in pregnant women with diabetes: a systematic review and meta-analysis

Do glycaemic treatment targets affect the perinatal mental health status of women with gestational diabetes? - Data from the TARGET Trial

BACKGROUND

Gestational diabetes mellitus is associated with perinatal mental disorders. Effective management may reduce this risk, but there is little evidence on effects of different glycaemic treatment targets. We assessed whether tight glycaemic treatment targets compared with less-tight targets reduce the risk of poor mental health outcomes in women with gestational diabetes.

METHODS

This was a secondary analysis of data from women who consented to complete perinatal mental health questionnaires as participants in the TARGET Trial, a stepped-wedge cluster randomized trial in 10 hospitals in New Zealand. All hospitals initially used less tight glycaemic targets for management of gestational diabetes and were sequentially randomized, in clusters of two at 4-monthly intervals, to using tighter glycaemic targets. Data were collected from 414 participants on anxiety (6-item Spielberger State Anxiety scale), depression (Edinburgh Postnatal Depression Scale), and health-related quality of life (36-Item Short-Form General Health Survey) at the time of diagnosis (baseline), 36 weeks of gestation, and 6 months postpartum. The primary outcome was composite poor mental health (any of anxiety, vulnerability to depression, or poor mental health-related quality of life). Generalized linear mixed models were used to determine the main treatment effect with 95% confidence intervals using an intention-to-treat approach.

RESULTS

We found no differences between randomised glycaemic target groups in the primary outcome at 36 weeks' (relative risk (RR): 1.07; 95% confidence interval 0.58, 1.95) and 6 months postpartum (RR: 1.03; 0.58, 1.81). There were similarly no differences in the components of the primary outcome at 36 weeks' [anxiety (RR: 0.85; 0.44, 1.62), vulnerability to depression (RR: 1.10; 0.43, 2.83), or poor mental health-related quality of life (RR: 1.05; 0.50, 2.20)] or at 6 months postpartum [anxiety (RR:1.21; 0.59, 2.48), vulnerability to depression (RR:1.41; 0.53, 3.79), poor mental health-related quality of life (RR: 1.11; 0.59, 2.08)].

CONCLUSION

We found no evidence that adoption of tighter glycaemic treatment targets in women with gestational diabetes alters their mental health status at 36 weeks' gestation and at 6 months postpartum.

TRIAL REGISTRATION

The Australian New Zealand Clinical Trials Registry (ANZCTR). ACTRN12615000282583 (ANZCTR-Registration). Date of registration: 25 March 2015.

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.

Glycemic status during pregnancy according to fasting and post-load glucose values: The association with adverse pregnancy outcomes. An observational study

AIM

Prognosis of treated hyperglycemia in pregnancy (HIP) may differ according to whether diagnosis following an oral glucose tolerance test (OGTT) is based on high fasting and/or high post-load glucose values.

METHODS

From a multiethnic prospective study, we included 8,339 women screened for HIP after 22 weeks of gestation. We evaluated the risk of large-for-gestational-age (LGA) infant (primary endpoint) and other adverse pregnancy outcomes according to HIP status in four groups defined as follows: no HIP (n = 6,832, reference); isolated fasting HIP (n = 465), isolated post-load HIP (n = 646), and fasting and post-load HIP (n = 396).

RESULTS

After adjusting for age, body mass index, ethnicity, smoking during pregnancy and parity, compared with no HIP, the adjusted odds ratios [95% confidence interval] for LGA infant were higher in the isolated fasting HIP (1.47 [1.11-1.96]) and fasting and post-load HIP (1.65 [1.23-2.21]) groups, but not in the isolated post-load HIP (1.13 [0.86-1.48]) group. The adjusted odds ratios for preterm delivery and neonatal intensive care unit were higher in the post-load HIP group (1.44 [1.03-2.03] and 1.28 [1.04-1.57], respectively), the fasting and post-load HIP group (1.81 [1.23-2.68] and 1.42 [1.10-1.81], respectively) but not in the isolated fasting HIP group (1.34 [0.90-2.00] and 1.20 [0.94-1.52], respectively).

CONCLUSION

Despite glucose-lowering care and adjustment for confounders, compared with no HIP, fasting HIP was associated with a higher rate of LGA infant, whereas post-load HIP was associated with higher preterm delivery and neonatal intensive care unit admission rates.

Placental abnormalities in type 1 and type 2 diabetes mellitus: a systematic review and metaanalysis of shear wave elastography

OBJECTIVE

This study aimed to describe the placental changes occurring in women with preexisting diabetes mellitus and to determine if elastography can detect placental changes in vivo.

DATA SOURCES

PubMed, Embase, Medline, and Cochrane were searched to identify English language studies published until July 2020.

STUDY ELIGIBILITY CRITERIA

1) For key question 1, studies that described histopathologic changes in placentas from women with known diabetes mellitus and 2) for key question 2, those that described structural-placental changes detectable by elastography in high-risk pregnancies (eg, those complicated by preeclampsia and/or fetal growth restriction), were included.

METHODS

For key question 1, we grouped placental pathologies using the Amsterdam International Consensus Group definitions. For key question 2, we conducted a metaanalysis including all data from studies reporting placental stiffness in meters per second (m/s) or kilopascals (kPa). The mean difference (95% confidence interval) was calculated using a random effects model.

RESULTS

Data were extracted from 14 studies of placental histopathology in women with known diabetes. In this group, a wide variety of placental histopathologic changes are described, though none are considered pathognomonic. The histopathologic changes including maternal vascular malperfusion, fetal vascular malperfusion, and/or infectious/inflammatory/other changes were divided into 3 broad categories on the basis of presumed etiology. A total of 15 studies reported the placental stiffness scores in women with a high-risk pregnancy vs those with a normal pregnancy. Only 1 reported stiffness scores for placentas in women with preexisting diabetes mellitus (N<10 women). Pooled analysis of 14 studies with available data included 478 "high-risk pregnancies" and 828 control or healthy pregnancies. Maternal-derived pathologies resulted in higher placental stiffness (mean difference 4.5 kPa [95% confidence interval, 3.16-5.87]) compared with control or healthy pregnancies. Fetal-derived pathologies also resulted in higher placental stiffness (mean difference of 6.5 kPa [95% confidence interval, 1.08-11.86]) compared with control or healthy pregnancies.

CONCLUSION

Shear wave elastography may provide an in vivo approximation of placental histopathology in women with certain kinds of high-risk pregnancies. A high-risk pregnancy may involve maternal- and fetal-derived pathologies. Further studies, particularly in women with preexisting diabetes, are needed to confirm this observation.

Tighter or less tight glycaemic targets for women with gestational diabetes mellitus for reducing maternal and perinatal morbidity: A stepped-wedge, cluster-randomised trial

BACKGROUND

Treatment for gestational diabetes mellitus (GDM) aims to reduce maternal hyperglycaemia. The TARGET Trial assessed whether tighter compared with less tight glycaemic control reduced maternal and perinatal morbidity.

METHODS AND FINDINGS

In this stepped-wedge, cluster-randomised trial, identification number ACTRN12615000282583, 10 hospitals in New Zealand were randomised to 1 of 5 implementation dates. The trial was registered before the first participant was enrolled. All hospitals initially used less tight targets (fasting plasma glucose (FPG) <5.5 mmol/L (<99 mg/dL), 1-hour <8.0 mmol/L (<144 mg/dL), 2 hour postprandial <7.0 mmol/L (<126 mg/dL)) and every 4 months, 2 hospitals moved to use tighter targets (FPG ≤5.0 mmol/L (≤90 mg/dL), 1-hour ≤7.4 mmol/L (≤133 mg/dL), 2 hour postprandial ≤6.7 mmol/L) (≤121 mg/dL). Women with GDM, blinded to the targets in use, were eligible. The primary outcome was large for gestational age. Secondary outcomes assessed maternal and infant health. Analyses were by intention to treat. Between May 2015 and November 2017, data were collected from 1,100 women with GDM (1,108 infants); 598 women (602 infants) used the tighter targets and 502 women (506 infants) used the less tight targets. The rate of large for gestational age was similar between the treatment target groups (88/599, 14.7% versus 76/502, 15.1%; adjusted relative risk [adjRR] 0.96, 95% confidence interval [CI] 0.66 to 1.40, P = 0.839). The composite serious health outcome for the infant of perinatal death, birth trauma, or shoulder dystocia was apparently reduced in the tighter group when adjusted for gestational age at diagnosis of GDM, BMI, ethnicity, and history of GDM compared with the less tight group (8/599, 1.3% versus 13/505, 2.6%, adjRR 0.23, 95% CI 0.06 to 0.88, P = 0.032). No differences were seen for the other infant secondary outcomes apart from a shorter stay in intensive care (P = 0.041). Secondary outcomes for the woman showed an apparent increase for the composite serious health outcome that included major haemorrhage, coagulopathy, embolism, and obstetric complications in the tighter group (35/595, 5.9% versus 15/501, 3.0%, adjRR 2.29, 95% CI 1.14 to 4.59, P = 0.020). There were no differences between the target groups in the risk for pre-eclampsia, induction of labour, or cesarean birth, but more women using tighter targets required pharmacological treatment (404/595, 67.9% versus 293/501, 58.5%, adjRR 1.20, 95% CI 1.00 to 1.44, P = 0.047). The main study limitation is that the treatment targets used may vary to those in use in some countries.

CONCLUSIONS

Tighter glycaemic targets in women with GDM compared to less tight targets did not reduce the risk of a large for gestational age infant, but did reduce serious infant morbidity, although serious maternal morbidity was increased. These findings can be used to aid decisions on the glycaemic targets women with GDM should use.

TRIAL REGISTRATION

The Australian New Zealand Clinical Trials Registry (ANZCTR). ACTRN12615000282583.

The influence of maternal blood glucose during pregnancy on weight outcomes at birth and preschool age in offspring exposed to hyperglycemia first detected during pregnancy, in a South African cohort

Introduction

Little is known about the influence of hyperglycemia first detected in pregnancy (HFDP) on weight outcomes in exposed offspring in Africa. We investigated the influence of maternal blood glucose concentrations during pregnancy on offspring weight outcomes at birth and preschool age, in offspring exposed to HFDP, in South Africa.

Research design and methods

Women diagnosed with HFDP had data routinely collected during the pregnancy and at delivery, at a referral hospital, and the offspring followed up at preschool age. Maternal fasting, oral glucose tolerance test 1 and 2-hour blood glucose were measured at diagnosis of HFDP and 2-hour postprandial blood glucose during the third trimester. Offspring were classified as either those exposed to diabetes first recognized in pregnancy (DIP) or gestational diabetes (GDM). At birth, neonates were classified into macrosomia, low birth weight (LBW), large for gestational age (LGA), appropriate (AGA) and small for gestational age (SGA)groups. At preschool age, offspring had height and weight measured and Z-scores for weight, height and BMI calculated.

Results

Four hundred and forty-three neonates were included in the study at birth, with 165 exposed to DIP and 278 exposed to GDM. At birth, the prevalence of LGA, macrosomia and LBW were 29.6%, 12.2% and 7.5%, respectively, with a higher prevalence of LGA and macrosomia in neonates exposed to DIP. At pre-school age, the combined prevalence of overweight and obesity was 26.5%. Maternal third trimester 2-hour postprandial blood glucose was significantly associated with z-scores for weight at birth and preschool age, and both SGA and LGA at birth.

Conclusion

In offspring exposed to HFDP, there is a high prevalence of LGA and macrosomia at birth, and overweight and obesity at preschool age, with higher prevalence in those exposed to DIP, compared to GDM. Maternal blood glucose control during the pregnancy influences offspring weight at birth and preschool age.

Diagnosis and Management of Gestational Diabetes Mellitus: An Overview of National and International Guidelines

Importance

Gestational diabetes mellitus (GDM) represents one of the most frequent complications of pregnancy and is associated with increased maternal and neonatal morbidity. Its incidence is rising, mostly due to an increase in maternal age and maternal obesity rate.

Objective

The aim of this study was to review and compare the recommendations of the most recently published guidelines on the diagnosis and management of this condition.

Evidence Acquisition

A descriptive review of guidelines from the National Institute for Health and Care Excellence (NICE), the International Federation of Gynecology and Obstetrics, the Australasian Diabetes in Pregnancy Society (ADIPS), the Society of Obstetricians and Gynecologists of Canada (SOGC), the American College of Obstetricians and Gynecologists (ACOG), the American Diabetes Association, and the Endocrine Society on gestational diabetes mellitus was carried out.

Results

The NICE guideline recommends targeted screening only for women with risk factors, whereas the International Federation of Gynecology and Obstetrics, ADIPS, SOGC, and the ACOG recommend screening for all pregnant women at 24 to 28 weeks of gestation in order to diagnose and effectively manage GDM; they also state that women with additional risk factors should be screened earlier (ie, in the first trimester) and retested at 24 to 28 weeks, if the initial test is negative. These guidelines describe similar risk factors for GDM and suggest the same thresholds for the diagnosis of GDM when using a 75-g 2-hour oral glucose tolerance test. Of note, the NICE only assesses the fasting and the 2-hour postprandial glucose levels for the diagnosis of GDM. Moreover, the SOGC and the ACOG do not recommend this test as the optimal screening method. The Endocrine Society alone, on the other hand, recommends the universal testing of all pregnant women for diabetes before 13 weeks of gestation or as soon as they attend the antenatal service and retesting at 24 to 28 weeks if the initial results are normal. In addition, there is a general consensus on the appropriate ultrasound surveillance of pregnancies complicated with GDM, and all the medical societies, except the ADIPS, recommend self-monitoring of capillary glucose to assess the glycemic control and set the same targets for fasting and postprandial glucose levels. There is also agreement that lifestyle modifications should be the first-line treatment; however, the reviewed guidelines disagree on the medical management of GDM. In addition, there are controversies regarding the timing of delivery, the utility of hemoglobin A_1c measurement, and the postpartum and lifelong screening for persistent hyperglycemia and type 2 diabetes. However, all the guidelines state that all women in pregnancies complicated by GDM should undergo a glycemic test at around 6 to 12 weeks after delivery. Finally, there is a universal consensus on the importance of breastfeeding and preconception screening before future pregnancies.

Conclusions

As GDM is an increasingly common complication of pregnancy, it is of paramount importance that inconsistencies between national and international guidelines should encourage research to resolve the issues of controversy and allow uniform international protocols for the diagnosis and management of GDM, in order to safely guide clinical practice and subsequently improve perinatal and maternal outcomes.

Continuous Glucose Monitoring Versus Self-Monitoring of Blood Glucose to Assess Glycemia in Gestational Diabetes

Background: Gestational diabetes mellitus (GDM) management using self-monitoring blood glucose (SMBG) does not normalize pregnancy outcomes. Objective: We aimed to conduct an observational study to explore if continuous glucose monitoring (CGM) could identify elevated glucose levels not apparent in women with GDM managed using SMBG. Study Design: A 7-day masked-CGM (iPro; Medtronic) was performed within 2 weeks of GDM diagnosis, immediately post-GDM education, but before insulin commencement as determined by SMBG. CGM data regarding hyperglycemia (sensor glucose >126 mg/dL [06:00-00:00 h] and >99 mg/dL [00:00-06:00 h] for >10% of time), time with health care professionals, treatment, and pregnancy outcome were collected. Comparisons (Mann-Whitney test) were performed between subjects subsequently commenced on insulin versus those continued with diet and lifestyle measures alone. Results: Ninety women of mean (standard deviation) gestational age weeks 27(1) were studied. Those prescribed insulin (n = 34) compared with those managed with diet and lifestyle alone (n = 56) had a greater time in hyperglycemia (P = 0.0001). Of those not prescribed insulin, 35/56 (61%) breached CGM cutoffs between 00:00 and 06:00 h; 11/56 (20%) breached 6.00-00.00 h CGM cutoffs for >10% of the time; and 21/45 (47%) with optimal CGM glucose levels during the daytime spent >10% time in hyperglycemia between 00.00 and 06:00 h. In contrast, SMBG measurements exceeded the clinical targets of <120 mg/dL postdinner in 5.4% and <100 mg/dL fasting in 0% of the subjects. Conclusions: CGM provides a more comprehensive assessment of nocturnal hyperglycemia than SMBG and could improve targeting of interventions in GDM. Larger studies to better define CGM targets are required, which once established will inform studies aimed at targeting nocturnal glucose levels.

Impact of different glycaemic treatment targets on pregnancy outcomes in gestational diabetes

AIM

With no current randomized trials, we explored the impact of tight compared with standard treatment targets on pregnancy outcomes in gestational diabetes mellitus (GDM).

METHODS

This cohort study of singleton births ≥ 28 weeks' gestation was conducted at two major Australian maternity services (2009-2013). Standardized maternal, neonatal and birth outcomes were examined using routine healthcare data and compared for women with GDM at Service One (n = 2885) and Service Two (n = 1887). Services applied different treatment targets: Service One (standard targets, reference group) fasting < 5.5 mmol/l, 2-h postprandial < 7.0 mmol/l; Service Two (tight targets) fasting < 5.0 mmol/l, 2-h postprandial < 6.7 mmol/l. Multivariable regression with propensity score adjustment was used to examine associations between targets and outcomes.

RESULTS

GDM prevalence and insulin use were 7.9% and 31% at Service One, and 5.7% and 46% at Service Two. There were no differences in primary outcomes: birthweight > 90th centile [adjusted odds ratio (OR) 1.06, 95% confidence interval (CI) 0.87-1.30] and < 10th centile (OR 0.84, 95% CI 0.70-1.01), or secondary outcomes gestational hypertension, pre-eclampsia, shoulder dystocia or a perinatal composite. Service Two with tight targets had increased induction of labour (OR 3.63, 95% CI 3.17-4.16), elective Caesarean section (OR 1.75, 95% CI 1.37-2.23) and Apgar scores < 7 at 5 min (OR 1.54, 95% CI 1.05-2.25), decreased hypoglycaemia (OR 0.76, 95% CI 0.61-0.94]), jaundice (OR 0.47, 95% CI 0.35-0.63) and respiratory distress (OR 0.68, 95% CI 0.47-0.98).

CONCLUSIONS

Tight GDM treatment targets were associated with greater insulin use and no difference in primary birthweight outcomes. The service with tight targets had higher obstetric intervention, lower rates of reported hypoglycaemia, jaundice, respiratory distress and lower Apgar scores. High-quality interventional data are required before tight treatment targets can be implemented.

Tight or less tight glycaemic targets for women with gestational diabetes mellitus for reducing maternal and perinatal morbidity? (TARGET): study protocol for a stepped wedge randomised trial

Background

Gestational diabetes mellitus (GDM) is strongly associated with significant adverse maternal and perinatal health outcomes that have lifelong consequences. Treatment for women with GDM aims to normalise maternal blood glucose concentrations to reduce these adverse health risks. Target recommendations for glycaemic control in women with GDM vary amongst international organisations. All their recommendations rely on consensus, as there have been no published randomised trials that compare different intensities of glucose control in women with GDM. The TARGET Trial aims to determine whether tighter targets for glycaemic control in women with GDM compared with less tight targets, reduce maternal and perinatal morbidity without adverse health consequences.

Methods/design

Using a stepped wedge, cluster randomised trial the 10 participating hospitals will be randomised to the timing of the change from the less tight to the tighter glycaemic target period. During the less tight target period, all health professionals at the hospital will aim to use the less tight glycaemic targets for treatment of women with GDM (fasting plasma glucose < 5.5 mmol/L; 1 h postprandial < 8.0 mmol/L; 2 h postprandial < 7.0 mmol/L). During the tighter target period all health professionals at the hospital will aim to use the tighter glycaemic targets for treatment of women with GDM (fasting plasma glucose ≤5.0 mmol/L, 1 h postprandial ≤7.4 mmol/L; 2 h postprandial ≤6.7 mmol/L). The primary study outcome is large for gestational age infant (birth weight > 90th centile). A sample size of 1080 participants will detect a treatment difference of 6% in the proportion of large for gestational age babies from 13% with less tight glycaemic targets to 7% with tighter targets, assuming an intra-cluster correlation coefficient of 0.05.

Discussion

The TARGET Trial will provide high-level evidence of direct relevance for clinical practice. If tighter treatment targets for women with GDM clearly result in significantly fewer large for gestational age infants and less adverse maternal and perinatal outcomes then they should be recommended for women with GDM. This would be of great importance to these women, their children, health services and communities.

Trial registration

Australian New Zealand Clinical Trials Registry - ACTRN 12615000282583.

Glucose Targets and Insulin Choice in Pregnancy: What Has Changed in the Last Decade?

PURPOSE OF REVIEW

To review current glycaemic targets and the potential use of newer insulin formulations in pregnancy.

RECENT FINDINGS

The impact of stricter glycaemic control on perinatal outcomes remains controversial, showing conflicting results. Current ongoing randomised trials investigating the role of tighter glucose targets in pregnancy should help clarify the benefit of tighter glucose control. Optimal timing for self-monitoring blood glucose (SMBG) remains debatable. Data suggest that post-prandial SMBG, particularly at 1 h, offers the best prediction of adverse perinatal outcome. To achieve these targets, insulin is the standard therapy. Novel insulin formulations offer benefits outside of pregnancy. Recent data on the use of new insulins in pregnancy (e.g. insulin degludec and glargine (U 300)) is limited to case reports. Glycaemic targets have remained unchanged in the last decade. Studies using stricter glycaemic targets may improve perinatal outcomes. Newer insulin formulations may offer increased flexibility and glycaemic control. Clinicians caring for women with diabetes striving to minimise adverse perinatal outcomes will find this review of interest.

Gestational Diabetes Mellitus (GDM): Relationship Between Higher Cutoff Values for 100 g Oral Glucose Tolerance Test (OGTT) and Insulin Requirement During Pregnancy

Objectives To study if there is any relationship about higher cutoff values for 100 g oral glucose tolerance test and the need for insulin in women diagnosed with gestational diabetes. Materials and Methods This is a retrospective population-based study of 201 women diagnosed with Gestational Diabetes Mellitus (GDM) between January 2012 and June 2014 in the area of Oviedo, Asturias, Spain. According to diagnostic criteria recommended by GEDE, NDDG, gestational diabetes is diagnosed if two or more plasma glucose levels meet or exceed the following threshold: fasting glucose of 105 mg/dl, 1-h 190 mg/dl, 2-h 165 mg/dl, or 3-h 145 mg/dl. We aim to know if there is any relationship between higher cutoffs and insulin requirement. Results 36 out of 201 patients (17.91%) needed insulin to achieve the targets of blood glucose control. There were no differences in mean maternal age and birthweights. Fasting blood glucose levels were significantly higher in women with further need for insulin than those who only needed diet and exercise (p < 0.001). Also, blood glucose levels 2 h after the oral glucose intake were statistically different between the two groups (p 0.032). AUC for fasting glucose value was the highest according to ROC curve. Conclusions Fasting cutoff vales for 100 g oral glucose tolerance test are consistently higher in women diagnosed with Gestational Diabetes that further needed insulin to achieve adequate blood glucose control. The positive predictive value of fasting glucose value 105 mg/dl on OGTT was 81.1%, whereas for the cut-off 95 mg/dl it was 54.0%.

Controversies and Advances in Gestational Diabetes-An Update in the Era of Continuous Glucose Monitoring

Diabetes in pregnancy, both preexisting type 1 or type 2 and gestational diabetes, is a highly prevalent condition, which has a great impact on maternal and fetal health, with short and long-term implications. Gestational Diabetes Mellitus (GDM) is a condition triggered by metabolic adaptation, which occurs during the second half of pregnancy. There is still a lot of controversy about GDM, from classification and diagnosis to treatment. Recently, there have been some advances in the field as well as recommendations from international societies, such as how to distinguish previous diabetes, even if first recognized during pregnancy, and newer diagnostic criteria, based on pregnancy outcomes, instead of maternal risk of future diabetes. These new recommendations will lead to a higher prevalence of GDM, and important issues are yet to be resolved, such as the cost-utility of this increase in diagnoses as well as the determinants for poor outcomes. The aim of this review is to discuss the advances in diagnosis and classification of GDM, as well as their implications in the field, the issue of hyperglycemia in early pregnancy and the role of hemoglobin A1c (HbA1c) during pregnancy. We have looked into the determinants of the poor outcomes predicted by the diagnosis by way of oral glucose tolerance tests, highlighting the relevance of continuous glucose monitoring tools, as well as other possible pathogenetic factors related to poor pregnancy outcomes.

Factors associated with patients with gestational diabetes in Japan being at increased risk of requiring intensive care

OBJECTIVE

To investigate factors associated with high-risk gestational diabetes (GDM) among patients with GDM.

METHODS

The present retrospective study included women with singleton pregnancies diagnosed with GDM using International Association of Diabetes and Pregnancy Study Group criteria at a single tertiary perinatal care center in Japan between July 1, 2010, and October 31, 2014. High-risk GDM was defined as patients who required at least 20 units of insulin therapy a day, delivering a large-for-gestational age neonate regardless of insulin therapy, or both. Maternal characteristics and diagnostic test results were investigated to identify associations with the high-risk criteria, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Among 217 patients, 95 (43.8%) were categorized as high risk. After adjusting for confounders, a fasting plasma glucose level at diagnosis of at least 4.66 mmol/L (adjusted OR 2.88, 95% CI 1.51-5.58) and pre-pregnancy body mass index (calculated as weight in kilograms divided by the square of height in meters) of at least 24 (adjusted OR 3.27, 95% CI 1.60-6.90) were independently associated with meeting the high-risk criteria.

CONCLUSION

Among Japanese patients with GDM, pre-pregnancy body mass index and fasting plasma glucose levels could be used to identify high-risk patients requiring intensive care during pregnancy.

Obstructive sleep apnea and diet-controlled gestational diabetes

BACKGROUND

Obstructive sleep apnea (OSA) was shown to be associated with gestational diabetes mellitus (GDM). However, prevalence of OSA in GDM women, its relationship to metabolic control, and predictive factors have not been studied.

MATERIAL AND METHODS

Eighty-two obese pregnant women with diet-controlled GDM between 24 and 34 weeks of gestation participated. The Berlin questionnaire was used to assess OSA symptoms. OSA was diagnosed using an overnight monitor. Fasting glucose and hemoglobin A1c (HbA1c) were obtained. Those with OSA underwent meal tolerance test (MTT) to assess their metabolic parameters. Classification tree analysis was used to develop a screening tool for OSA.

RESULTS

At a median gestational age of 29 weeks, OSA was diagnosed in 52.4% of the women, with a median apnea hypopnea index of 9.4 (interquartile range 6.4, 12.4). More severe OSA was significantly correlated with higher fasting glucose but not HbA1c. For those with OSA, sleep parameters related to oxygen desaturation significantly correlated with higher fasting insulin resistance and more severe β-cell dysfunction, as evaluated by MTT. A screening tool involving two variables, neck circumference and Berlin Questionnaire score, was developed. The sensitivity and specificity were 86% and 51%, respectively. The overall accuracy was 70%.

CONCLUSION

OSA is prevalent in obese pregnant women with diet-controlled GDM in the late second to early third trimester. OSA severity, especially the degree of oxygen desaturation, correlated with fasting glucose, insulin resistance, and β-cell function. A simple screening tool involving the Berlin Questionnaire and neck circumference can aid in predicting OSA in this patient group.

Fasting target for hyperglycaemia in pregnancy

Knowledge of the fasting plasma glucose of healthy women may assist in the setting of treatment targets for women with hyperglycaemia in pregnancy (HIP). This study examines the pregnancy glucose tolerance test results of 3344 women without HIP collected over a three-year period. The median fasting plasma glucose was 4.4 mmol/L with an interquartile range of 4.2-4.6 mmol/L and a 5th to 95th centile of 3.8-4.9 mmol/L. As the diagnostic fasting glucose level for HIP is ≥5.1 mmol/L, these data support a treatment target of ≤5.0 mmol/L.

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.

Glycemic targets in pregnancies affected by diabetes: historical perspective and future directions

The definition of optimal glycemic control in pregnancies affected by diabetes remains enigmatic. Diabetes phenotypes are heterogeneous. Moreover, fetal macrosomia insidiously occurs even with excellent glycemic control. Current blood glucose (BG) targets (FBG ≤95, 1-h post-prandial <140, 2 h <120 mg/dL) have improved perinatal outcomes, but arguably they have not normalized. The conventional management approach has been to replicate a pattern of glycemia in normal pregnancy. Although these patterns are lower than previously appreciated, a randomized controlled trial (RCT) has never compared current vs. lower glucose targets powered on maternal/fetal outcomes. This paper provides historical context to the current targets by reviewing evidence supporting their evolution. Using lower targets (FBG <90, 1 h <122, 2 h <110, mean BG ≤95 mg/dL) may help normalize outcomes, but phenotypic differences (type 1 vs. type 2 vs. gestational diabetes) might require different glycemic goals. There remains a critical need for well-designed RCTs to confirm optimal glycemic control that minimizes both small for and large for gestational age across pregnancies affected by diabetes.

Screening and management of gestational diabetes

Gestational diabetes (GDM) is a frequent medical condition during pregnancy. It is associated with an increased risk of complications for both the mother and the baby during pregnancy and post partum. The International Association of Diabetes and Pregnancy Study Groups (IADPSG) has proposed a new screening strategy for overt diabetes in pregnancy and screening for GDM. However, there is still a lack of international uniformity in the approach to the screening and diagnosis of GDM. Controversies include universal versus selective screening, the optimal time for screening, appropriate tests and cutoff values, and whether testing should be conducted in one or two steps. This review gives an update on screening for GDM and overt diabetes during pregnancy. We also give an overview on the medical and obstetrical management of GDM.

Changing perspectives in pre-existing diabetes and obesity in pregnancy: maternal and infant short- and long-term outcomes

PURPOSE OF REVIEW

Climbing obesity rates in women have propelled the increasing prevalence of type 2 diabetes mellitus (T2DM) in pregnancy, and an increasing number of women with type 1 diabetes mellitus (T1DM) are also affected by obesity. Increasing recognition that an intrauterine environment characterized by obesity, insulin resistance, nutrient excess, and diabetes may be fueling the obesity epidemic in children has created enormous pressure to re-examine the conventional wisdom of our current approaches.

RECENT FINDINGS

Compelling data in pregnancies complicated by diabetes, in particular those accompanied by insulin resistance and obesity, support a fetal programming effect resulting in increased susceptibility to metabolic disease for the offspring later in life. Recent data also underscore the contribution of obesity, lipids, and lesser degrees of hyperglycemia on fetal fat accretion, challenging the wisdom of current gestational weight gain recommendations with and without diabetes. The risks of adverse pregnancy outcomes in T2DM are at least as high as in T1DM and there remains controversy about the ideal glucose treatment targets, the benefit of different insulin analogues, and the role of continuous glucose monitoring in T1DM and T2DM.

SUMMARY

It has become unmistakably evident that achieving optimal outcomes in mothers with diabetes is clearly impacted by ideal glycemic control but goes far beyond it. The intrauterine metabolic environment seems to have long-term implications on the future health of the offspring so that the effectiveness of our current approaches can no longer be simply measured by whether or not maternal glucose values are at goal.

Unresolved controversies in gestational diabetes: implications on maternal and infant health

PURPOSE OF REVIEW

Gestational diabetes mellitus (GDM) is a major public health concern because of rising rates and offspring consequences; yet, expert panels are in complete disagreement on how to diagnose and optimally treat GDM. This review underscores why there remains no diagnostic standard, no agreement on whether excess dietary carbohydrate or fat should be reduced, and whether oral hypoglycemic therapy is safe given the unknown offspring effects on hepatic, pancreatic, or fat development.

RECENT FINDINGS

New diagnostic criteria proposed by the American Diabetes Association would triple the prevalence of GDM (∼18%). Whether the treatment of women with these milder degrees of hyperglycemia will improve pregnancy outcomes is unknown given the powerful effect of obesity alone on excess fetal growth. There are data that restricting carbohydrate in the diet by substituting fat to blunt postprandial glucose levels may worsen maternal insulin resistance and that metformin may increase offspring subcutaneous fat.

SUMMARY

The adoption of the new American Diabetes Association diagnostic criteria for GDM was rejected by ACOG and not endorsed by the NIH. Yet, varying criteria are used by different centers resulting in confusion for both patient care and research. Both maternal diet and agents that cross the placenta could potentially modify offspring gene expression. Better identification and treatment of mothers and fetuses at risk may have far-reaching implications for maternal and child health.