The Incidence of Gestational Diabetes Mellitus in the Illawarra Area of New South Wales

The prevalence of gestational diabetes mellitus among Aboriginal and Torres Strait Islander women in Australia: a systematic review and meta-analysis

INTRODUCTION

Gestational diabetes mellitus (GDM) is an important and increasing health problem. This study aims to investigate and explain the marked variation in reported GDM prevalence among Australian Indigenous women.

MATERIALS AND METHODS

We searched five databases to August 2013 for studies of GDM prevalence; two people independently assessed search results, extracted data, and appraised risk of bias. Meta-analysis was conducted, and between-study heterogeneity examined using subgroup analyses. Within-study findings were synthesized narratively.

RESULTS

The pooled GDM prevalence from 23 of the 25 total studies (5.74%, 4.78-6.71) was similar to that reported in national studies, but heterogeneity was substantial (I(2)  = 97%), making conclusions from between-study comparisons difficult. The greatest reductions in heterogeneity were seen within subgroups using localized diagnostic criteria (I(2)  = 43%, 3 studies), universal screening (I(2)  = 58%) and some jurisdictions, probably reflecting proxy measures of increased consistency in diagnostic and screening methods. Insufficient data were available to assess the effect of factors such as rurality, diagnostic criteria, study design and data sources on prevalence. Synthesis of within-study findings showed: higher age-adjusted prevalences of GDM in Indigenous versus non-Indigenous women; Indigenous women have greater increases in prevalence with maternal age; and non-Indigenous women appear to have a steeper increase in GDM prevalence over time. Prevalence increased almost fourfold in two studies following introduction of universal screening when compared with selective risk-based screening, although numbers were small.

DISCUSSION/CONCLUSIONS

The published GDM prevalence among Indigenous women varies markedly, probably due to variation in diagnostic and screening practices.

The current state of Indigenous and Aboriginal women with diabetes in pregnancy: a systematic review

To undertake a systematic review of diabetes in pregnancy (DIP), determining prevalence and impact on maternal and child health outcomes for Indigenous and Aboriginal women.

METHOD

Electronic searches of MEDLINE, Embase, CINAHL, ERIC, DARE, CDSR, PsycINFO, Austhealth and HealthInfoNet were undertaken. Changes in diagnostic criteria for DIP and variability in methodology meant a qualitative synthesis of the data was undertaken.

RESULTS

From the 142 potential studies, 42 peer reviewed journal articles met the inclusion criteria. GDM prevalence in 65% of studies was greater for Indigenous and Aboriginal women than the comparison groups; Pacific Islander 8.1%, Canadian Aboriginal 11.5%, American Indian 7.9%, Australian Aboriginal 8.4% compared with 2-5% worldwide. Of studies reporting high birth weight (>4000 g) and DIP, 75% had a higher than expected prevalence, 86% had higher macrosomia prevalence and 63% had higher stillbirth rates. Studies with Alaskan, Australian Aboriginal and Pacific Islander women had GDM prevalence both greater and less than comparison groups.

CONCLUSION

Correcting the health disparity for Indigenous and Aboriginal women with DIP is a health priority. DIP prevalence is not the same for all Indigenous and Aboriginal women. Inconsistent study design without robust data is interfering with accurate prevalence of DIP. New international consensus guidelines provide opportunities for high quality studies of DIP for Indigenous and Aboriginal women.

International migration and gestational diabetes mellitus: a systematic review of the literature and meta-analysis

Influxes of migrant women of childbearing age to receiving countries have made their perinatal health status a key priority for many governments. The international research collaboration Reproductive Outcomes And Migration (ROAM) reviewed published studies to assess whether migrants in countries of resettlement have a greater risk of gestational diabetes mellitus (GDM) than women in receiving countries. A systematic review of the literature from Medline, Embase, PsychInfo and CINAHL from 1990 to 2009 included studies of migrant women and GDM. Studies were excluded if there was no cross-border movement or comparison group or if the receiving country was not the country of resettlement. Studies were assessed for quality, analysed descriptively and meta-analysed. Twenty-four reports (representing >120,000 migrants) met our inclusion criteria. Migrants were described primarily by geographic origin; other relevant aspects (e.g. time in country, language fluency) were rarely studied. Migrants' results for GDM were worse than those for receiving-country women in 79% of all studies. Meta-analyses showed that, compared with receiving-country women, Caribbean, African, European and Northern European women were at greater risk of GDM, while North Africans and North Americans had risks similar to receiving-country women. Although results of the 31 comparisons of Asians, East Africans or non-Australian Oceanians were too heterogeneous to provide a single GDM risk estimate for migrant women, only one comparison was below the receiving-country comparison group, all others presented a higher risk estimate. The majority of women migrants to resettlement countries are at greater risk for GDM than women resident in receiving countries. Research using clear, specific migrant definitions, adjusting for relevant risk factors and including other aspects of migration experiences is needed to confirm and understand these findings.

Effect of a low-glycemic-index diet during pregnancy on obstetric outcomes

BACKGROUND

Pregnancy is a condition in which the glycemic index (GI) may be of particular relevance because maternal glucose is the main energy substrate for intrauterine growth.

OBJECTIVE

The aim was to compare the effects of low-GI and conventional dietary strategies on pregnancy outcomes in healthy women. Compliance and acceptability were also investigated.

DESIGN

The subjects were assigned alternately to receive dietary counseling that encouraged either low-GI (LGI) carbohydrate foods or high-fiber, moderate-to-high GI (HGI) foods and were studied 5 times between <16 wk gestation and delivery. Of the 70 women who met the inclusion criteria, 62 completed the study (32 in the LGI and 30 in the HGI groups). Primary outcomes were measures of fetal size.

RESULTS

The mean diet GI fell significantly in the LGI group but not in the HGI group. Compared with the LGI group, women in the HGI group gave birth to infants who were heavier (3408 +/- 78 compared with 3644 +/- 90 g; P = 0.051) and had a higher birth centile (48 +/- 5 compared with 69 +/- 5; P = 0.005), a higher ponderal index (2.62 +/- 0.04 compared with 2.74 +/- 0.04; P = 0.03), and a higher prevalence of large-for-gestational age (3.1% compared with 33.3%; P = 0.01). Women in the LGI group found the diet easier to follow.

CONCLUSION

Because birth weight and ponderal index may predict chronic disease in later life, a low-GI diet may favorably influence long-term outcomes.

Advice that includes food sources of unsaturated fat supports future risk management of gestational diabetes mellitus

Abstract Women with gestational diabetes mellitus (GDM) have a greater risk of developing type 2 diabetes mellitus (DM) and heart disease than pregnant women without GDM. Advice given during the GDM pregnancy provides an opportunity to develop protective dietary patterns for the long-term management of this risk. Dietary guidelines for the prevention and management of type 2 DM support the inclusion of unsaturated fats, but food advice needs to target this outcome. The aim of this study was to compare the dietary intakes of women with GDM given general low-fat advice (control group) to women with GDM given the same advice with additional targets for food sources of unsaturated fats (intervention group). After approximately 6 weeks, the intervention group reported more ideal dietary fatty acid intakes than the control group, with polyunsaturated:saturated fat ratios of 1:1 and 0.4:1, respectively ( P < .001), assessed using repeated measures analysis of variance. These results confirm the need to include food sources of unsaturated fats in advice strategies to assure optimal protective eating habits in this at-risk group.

Gestational diabetes mellitus: Compliance with testing

An audit of birth records of two public and one private hospital was undertaken, over a 6-month period, to determine compliance with the local policy that all women are tested for gestational diabetes mellitus (GDM). Overall 92.1% of women were tested for GDM. When those women who delivered their babies early or who had no prenatal care were excluded, then there was 95.3% compliance with the advice for universal testing.

Population health significance of gestational diabetes

OBJECTIVE

Women who have had gestational diabetes mellitus (GDM) have a high risk of subsequently developing diabetes. However, the contribution of GDM toward the total population of people with diabetes, or its population health impact, has not been examined. Therefore, the aim of this study is to determine the population health significance of GDM by estimating the proportion of cases of diabetes in women that would have been preceded by a pregnancy complicated by GDM.

RESEARCH DESIGN AND METHODS

A MEDLINE search was conducted to identify controlled follow-up studies of women with GDM. Meta-analysis of these studies, using the Mantel-Haenszel method for pooling relative risks (RRs), provided an overall RR for the development of diabetes in women with GDM versus control women who had been pregnant without GDM. Recent large studies examining the prevalence of GDM were also reviewed. This enabled the calculation of the population-attributable risk (PAR) for these populations. In this case, the PAR represents the proportion of cases of diabetes among parous women that were associated with previous GDM.

RESULTS

From six controlled follow-up studies, the overall RR for developing diabetes after GDM was calculated to be 6.0 (95% CI 4.1-8.8). Applying this to the studies of GDM prevalence, the PAR for GDM ranged from 0.10 to 0.31 (i.e., 10-31% of parous women with diabetes would have experienced a GDM pregnancy earlier).

CONCLUSIONS

In some populations, women who have had GDM comprise a substantial proportion of subjects who ultimately develop diabetes. Effective measures to prevent women with GDM from progressing to frank diabetes could therefore have a significant population health impact.

Gestational diabetes in Victoria in 1996: incidence, risk factors and outcomes

OBJECTIVES

To describe the epidemiology of gestational diabetes mellitus (GDM) in Victoria.

STUDY DESIGN

Population study of all women having singleton births in Victoria in 1996.

METHODS

Probabilistic record linkage of routinely collected data and capture-recapture techniques to provide an estimate of the incidence of GDM.

MAIN OUTCOME MEASURES

Risk factors for and the adverse outcomes associated with GDM compared with the non-diabetic population by univariate and multivariate analysis.

RESULTS

The estimated incidence of GDM was 3.6% (95% confidence interval [CI], 3.60%-3.64%). GDM is associated with women who are older, Aboriginal, non-Australian born, or who give birth in a larger hospital. The adverse outcomes associated with GDM pregnancies were hypertension/pre-eclampsia (adjusted odds ratio [OR], 1.6; 95% CI, 1.4-1.9), hyaline membrane disease (1.6; 1.2-2.2), neonatal jaundice (1.4; 1.2-1.7) and macrosomia (2.0; 1.8-2.3). Interventions during childbirth were also associated with GDM - for example, induction of labour (3.0; 2.7-3.4) and caesarean section (1.7; 1.6-1.9).

CONCLUSION

Women with GDM had increased rates of hypertension, pre-eclampsia, induced labour, and interventional delivery. Their offspring had a higher risk of macrosomia, neonatal jaundice and hyaline membrane disease.

Prevalence of gestational diabetes mellitus in polycystic ovarian syndrome (PCOS) patients pregnant after ovulation induction with gonadotrophins

Our aims were: 1. To investigate if women with PCOS who become pregnant using gonadotrophins have a higher incidence of gestational diabetes mellitus (GDM) compared to spontaneously pregnant matched control women, 2. To compare the prevalence of GDM in PCOS women with that in women with hypo/eugonadotrophic hypogonadism and in unexplained infertility and 3. To investigate differences in pregnancy outcomes between the groups. This was a retrospective case-control study. Women with PCOS were matched with a control by age, BMI, and ethnicity. There were 60 women with PCOS, 11 with hypogonadotrophic hypogonadism, 6 with eugonadotrophic hypogonadism, and 12 with unexplained infertility. Control women were those who attended a major public hospital for antenatal care and delivery We found no difference in the prevalence of GDM between the PCOS (22%) and the controls (17%) or between the PCOS and other groups. Women with GDM (diet or insulin controlled) had a significantly higher BMI than women without GDM (p = 0.019). There was no difference in pregnancy outcomes between the groups. There was a significant dependence of babies' birthweight on mother's BMI (p<0.001).

Gestational diabetes mellitus; resource utilization and costs of diagnosis and treatment

The recommendation to test every woman for gestational diabetes mellitus (GDM) has a defined cost. The management of women diagnosed with GDM will use additional health resources. This examines the cost and resource utilization of a consecutive group of women diagnosed over a 1-year period. The cost of testing a woman for GDM is around $10.00 with slight variations depending on the testing procedure. The annual cost of testing in NSW would be less than 1 million dollars. Women diagnosed with GDM used the resources of a diabetes education centre for an average of 2.8 hours and attended for 3.4 (2.3) medical visits. Insulin was required by 18.7% of the women for 9.7 (4.7) weeks using 47.7 (21.2) units each day. Testing women for GDM is a low-cost item. Managing a woman diagnosed with GDM may cost several hundred dollars. Cost reductions could be made by reducing the amount of insulin used and by avoiding hospitalization.

Free fatty acids and gestational diabetes mellitus

Dyslipidaemia is a common finding in the syndrome of gestational diabetes mellitus (GDM). Free fatty acids (FFA) can cause insulin resistance and have a toxic effect on beta cell function. GDM is a syndrome due to insulin resistance and the purpose of this study was to examine FFA levels in pregnancy. For this purpose samples were taken from 44 consecutive women with GDM and 36 consecutive controls. The women with GDM had similar levels of insulin, triglycerides and total cholesterol to the controls but a significant elevation in FFA; 0.70 (0.33) mmol/L versus 0.29 (0.12) mmol/L (p < 0.0001).

Gestational diabetes: do all women need to be tested?

The results of glucose tolerance testing in 1,185 consecutive women were examined with respect to historical risk factors for gestational diabetes mellitus (GDM). GDM was present in 79 of 1,185 (6.7%) of the women. GDM was present in 8.5% of women aged > or = 30 years, in 12.3% of women with a preconception BMI > or = 30 and in 11.6% of women with a family history of diabetes in a first degree relation. A combination of one or all of these risk factors predicted GDM in only 48 of 79 (60.8%) cases. GDM was present in 4.8% of women without risk factors. Testing for GDM on the basis of these historical risk factors alone, and using the Australasian Diabetes in Pregnancy Society (ADIPS) criteria for diagnosis, would miss more than one-third of all cases. This study supports the ADIPS recommendation that there should be universal testing.

Is there a seasonal variation in the incidence of gestational diabetes?

It has been suggested that the incidence of gestational diabetes (GDM) may vary with different seasons of the year. The fasting and 2 h glucose levels after a 75 g glucose tolerance test were therefore examined in 2749 women being tested for GDM and were correlated with the mean temperature at 0900 h by month and by season. The mean monthly temperature ranged from 22.3 degrees C in January to 13.6 degrees C in July. The monthly incidence of GDM ranged from 3.5% (95% CI, 0.7-6.3) in September to 8.7% (4.7-12.7) in November. The seasonal incidence of GDM ranged from 7.4% (5.6-9.2) in autumn to 5.5% (3.5-7.5) in winter. Chi-squared analysis did not suggest a significant association between the proportion of women diagnosed with GDM and either the month (p = 0.47) or the season (p = 0.39). Multiple regression analysis, after correction for maternal age, parity, BMI, and the week of testing revealed a non-significant association between fasting glucose and monthly temperature (p = 0.36) and an increase in the 2 h glucose of 0.026 mmol l-1 for each increase of 1 degree C in temperature (p = 0.011). In a temperate coastal area of Australia these differences do not appear clinically significant and have not caused a variation in the incidence of GDM with different seasons.