Shoulder dystocia in babies born to Aboriginal mothers with diabetes: a population-based cohort study, 1998-2015.

BACKGROUND: Australian Aboriginal and Torres Strait Islander women with diabetes in pregnancy (DIP) are more likely to have glycaemic levels above the target range, and their babies are thus at higher risk of excessive fetal growth. Shoulder dystocia, defined by failure of spontaneous birth of fetal shoulder after birth of the head requiring obstetric maneuvers, is an obstetric emergency that is strongly associated with DIP and fetal size. The aim of this study was to investigate the epidemiology of shoulder dystocia in Aboriginal babies born to mothers with DIP. METHODS: Stratifying by Aboriginal status, characteristics of births complicated by shoulder dystocia in women with and without DIP were compared and incidence and time-trends of shoulder dystocia were described. Compliance with guidelines aiming at preventing shoulder dystocia in women with DIP were compared. Post-logistic regression estimation was used to calculate the population attributable fractions (PAFs) for shoulder dystocia associated with DIP and to estimate probabilities of shoulder dystocia in babies born to mothers with DIP at birthweights > 3 kg. RESULTS: Rates of shoulder dystocia from vaginal births in Aboriginal babies born to mothers with DIP were double that of their non-Aboriginal counterparts (6.3% vs 3.2%, p < 0.001), with no improvement over time. Aboriginal mothers with diabetes whose pregnancies were complicated by shoulder dystocia were more likely to have a history of shoulder dystocia (13.1% vs 6.3%, p = 0.032). Rates of guideline-recommended elective caesarean section in pregnancies with diabetes and birthweight > 4.5 kg were lower in the Aboriginal women (28.6% vs 43.1%, p = 0.004). PAFs indicated that 13.4% (95% CI: 9.7%-16.9%) of shoulder dystocia cases in Aboriginal (2.7% (95% CI: 2.1%-3.4%) in non-Aboriginal) women were attributable to DIP. Probability of shoulder dystocia among babies born to Aboriginal mothers with DIP was higher at birthweights > 3 kg. CONCLUSIONS: Aboriginal mothers with DIP had a higher risk of shoulder dystocia and a stronger association between birthweight and shoulder dystocia. Many cases were recurrent. These factors should be considered in clinical practice and when counselling women.

Overweight/obesity and other predictors of gestational diabetes among Aboriginal and non-Aboriginal women in Western Australia.

This population-based study investigated the association of BMI and other predictors with gestational diabetes mellitus (GDM) among Australian Aboriginal and non-Aboriginal mothers. We conducted a state-wide retrospective cohort study that included all singleton births in Western Australia (n = 134,552) between 2012 and 2015 using population health datasets linked by the Western Australian Data Linkage Branch. Associations between GDM and its predictors were estimated as adjusted relative risks (aRRs) from multivariable generalised linear models. Adjusted ratio of relative risks (aRRRs) compared RRs in Aboriginal and non-Aboriginal mothers. Adjusted population attributable fractions estimated the contribution of overweight/obesity to GDM burden, and adjusted predicted probabilities for GDM were plotted against BMI levels. The following predictors had stronger associations with GDM in Aboriginal, compared to non-Aboriginal, mothers: maternal obesity (aRR [95% CI] 3.16 [2.54-3.93]; aRRR 1.57 [1.26-1.94]), previous LGA (aRR 1.70 [1.37-2.12]; aRRR 1.41 [1.13-1.76]) and previous macrosomia (birthweight ≥ 4 kg) (aRR 1.55 [1.24-1.94]; aRRR 1.53 [1.22-1.91]). 46.1% (95% CI: 36.6-54.1) of GDM cases in Aboriginal women (23.3% in non-Aboriginal mothers, 95% CI: 21.6-25.1) were attributed to overweight/obesity. Compared to non-Aboriginal mothers, adjusted GDM probabilities were higher at all BMI levels and showed greater increase with BMI. Overweight/obesity is a key driver of GDM among Aboriginal women. Association between BMI and GDM is stronger in Aboriginal, compared to non-Aboriginal, women especially at higher BMI.

The impact of diabetes during pregnancy on neonatal outcomes among the Aboriginal population in Western Australia: a whole-population study.

BACKGROUND: Aboriginal and Torres Strait Islander (hereafter Aboriginal) women have a high prevalence of diabetes in pregnancy (DIP), which includes pre-gestational diabetes mellitus (PGDM) and gestational diabetes mellitus (GDM). We aimed to characterize the impact of DIP in babies born to Aboriginal mothers. METHODS: A retrospective cohort study, using routinely collected linked health data that included all singleton births (N = 510 761) in Western Australia between 1998 and 2015. Stratified by Aboriginal status, generalized linear mixed models quantified the impact of DIP on neonatal outcomes, estimating relative risks (RRs) with 95% CIs. Ratio of RRs (RRRs) examined whether RRs differed between Aboriginal and non-Aboriginal populations. RESULTS: Exposure to DIP increased the risk of adverse outcomes to a greater extent in Aboriginal babies. PGDM heightened the risk of large for gestational age (LGA) (RR: 4.10, 95% CI: 3.56-4.72; RRR: 1.25, 95% CI: 1.09-1.43), macrosomia (RR: 2.03, 95% CI: 1.67-2.48; RRR: 1.39, 95% CI: 1.14-1.69), shoulder dystocia (RR: 4.51, 95% CI: 3.14-6.49; RRR: 2.19, 95% CI: 1.44-3.33) and major congenital anomalies (RR: 2.14, 95% CI: 1.68-2.74; RRR: 1.62, 95% CI: 1.24-2.10). GDM increased the risk of LGA (RR: 2.63, 95% CI: 2.36-2.94; RRR: 2.00, 95% CI: 1.80-2.22), macrosomia (RR: 1.95, 95% CI: 1.72-2.21; RRR: 2.27, 95% CI: 2.01-2.56) and shoulder dystocia (RR: 2.78, 95% CI: 2.12-3.63; RRR: 2.11, 95% CI: 1.61-2.77). Birthweight mediated about half of the DIP effect on shoulder dystocia only in the Aboriginal babies. CONCLUSIONS: DIP differentially increased the risks of fetal overgrowth, shoulder dystocia and congenital anomalies in Aboriginal babies. Improving care for Aboriginal women with diabetes and further research on preventing shoulder dystocia among these women can reduce the disparities.

Trends and burden of diabetes in pregnancy among Aboriginal and non-Aboriginal mothers in Western Australia, 1998-2015.

BACKGROUND: Diabetes in pregnancy (DIP), which includes pre-gestational and gestational diabetes, is more prevalent among Aboriginal women. DIP and its adverse neonatal outcomes are associated with diabetes and cardiovascular disease in the offspring. This study investigated the impact of DIP on trends of large for gestational age (LGA) in Aboriginal and non-Aboriginal populations, and added to the limited evidence on temporal trends of DIP burden in these populations. METHODS: We conducted a retrospective cohort study that included all births in Western Australia between 1998 and 2015 using linked population health datasets. Time trends of age-standardised and crude rates of pre-gestational and gestational diabetes were estimated in Aboriginal and non-Aboriginal mothers. Mixed-effects multivariable logistic regression was used to estimate the association between DIP and population LGA trends over time. RESULTS: Over the study period, there were 526,319 births in Western Australia, of which 6.4% were to Aboriginal mothers. The age-standardised annual rates of pre-gestational diabetes among Aboriginal mothers rose from 4.3% in 1998 to 5.4% in 2015 and remained below 1% in non-Aboriginal women. The comparable rates for gestational diabetes increased from 6.7 to 11.5% over the study period in Aboriginal women, and from 3.5 to 10.2% among non-Aboriginal mothers. LGA rates in Aboriginal babies remained high with inconsistent and no improvement in pregnancies complicated by gestational diabetes and pre-gestational diabetes, respectively. Regression analyses showed that DIP explained a large part of the increasing LGA rates over time in Aboriginal babies. CONCLUSIONS: There has been a substantial increase in the burden of pre-gestational diabetes (Aboriginal women) and gestational diabetes (Aboriginal and non-Aboriginal) in recent decades. DIP appears to substantially contribute to increasing trends in LGA among Aboriginal babies.

Metformin and Vitamin B12 Deficiency: Where Do We Stand?

The association between metformin use and low vitamin B12 levels in type 2 diabetes mellitus patients is well-established. However, many aspects of the topic remain to be elucidated. There is still controversy on the current diagnostic approaches to vitamin B12 deficiency. It is now believed that measuring the serum levels of the vitamin may not reflect its metabolic status. Moreover, there were conflicting results from studies attempting to quantify and explore metformin-associated vitamin B12 deficiency and its clinical impacts. This article reviews the cellular functions of vitamin B12, the biomarkers utilized to define the vitamin deficiency and metformin-induced vitamin B12 deficiency with an emphasis on its prevalence and clinical impacts. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.