Effects of ethnicity on glucose tolerance, insulin resistance and beta cell function in 223 women with an abnormal glucose challenge test during pregnancy

Management of gestational diabetes mellitus via nutritional interventions: The relevance of gastric emptying

Gestational diabetes mellitus (GDM) represents one of the most common medical complications of pregnancy and is important to the well-being of both mothers and offspring in the short and long term. Lifestyle intervention remains the mainstay for the management of GDM. The efficacy of nutritional approaches (e.g. calorie restriction and small frequent meals) to improving the maternal-neonatal outcomes of GDM was attested to by Chinese population data, discussed in two articles in recent issues of this journal. However, a specific focus on the relevance of postprandial glycaemic control was lacking. Postprandial rather than fasting hyperglycaemia often represents the predominant manifestation of disordered glucose homeostasis in Chinese women with GDM. There is now increasing appreciation that the rate of gastric emptying, which controls the delivery of nutrients for digestion and absorption in the small intestine, is a key determinant of postprandial glycaemia in both health, type 1 and 2 diabetes. It remains to be established whether gastric emptying is abnormally rapid in GDM, particularly among Chinese women, thus contributing to a predisposition to postprandial hyperglycaemia, and if so, how this influences the therapeutic response to nutritional interventions. It is essential that we understand the role of gastric emptying in the regulation of postprandial glycaemia during pregnancy and the potential for its modulation by nutritional strategies in order to improve post-prandial glycaemic control in GDM.

An evaluation of dietary intakes of a selected group of South Asian migrant women with gestational diabetes mellitus

Background: Women of South Asian descent have an increased risk of developing gestational diabetes mellitus (GDM), and type 2 diabetes mellitus compared to Caucasian women. Dietary advice provided by health practitioners to this group has been found to be culturally inappropriate. The aim of this study was to describe the dietary intakes of South Asian women with gestational diabetes and use this information to develop culturally appropriate dietary models for education and support of dietary management.Method: An in-depth diet and lifestyle survey was administered with 13 eligible women. Dietary histories were collected for pre-pregnancy, during pregnancy and post-GDM diagnosis to evaluate changes in dietary intake, diet and health beliefs and traditional foods consumed during pregnancy.Results: The diets of participants did not meet nutrient requirements for pregnancy; specific areas on concern were dietary fibre, calcium, iron, folate and iodine. Vegetarians were particularly at risk with regards to energy and protein intake. Generally dietary intakes of these women with GDM were not consistent with guidelines for management of GDM. Confusion about what they should eat for GDM, health practitioner advice and conflict with cultural expectations about foods to consume during pregnancy was evident.Conclusion: The dietary information collected from these women was used to model sample menus for GDM that were culturally appropriate and consistent with vegetarian and non-vegetarian eating patterns.

Seasonality of gestational diabetes mellitus and maternal blood glucose levels: Evidence from Taiwan

Previous studies have indicated that the prevalence of gestational diabetes mellitus (GDM) was related to the season. However, there was no relevant information in Asia. The aim of this study was to determine whether there was seasonality of GDM and maternal blood glucose level in Taiwanese women.A total of 6396 pregnancies were enrolled between 2012 and 2014 in this retrospective study. A 2-step approach according to the Carpenter-Coustan criteria was used for GDM diagnosis. A generalized linear mixed model was used to estimate the effect of season on GDM diagnosis by adjusting for age, prepregnancy body mass index, parity, history of GDM, fetal sex, and the rate of weight gain.During the study period, 418 (6.5%) pregnancies were diagnosed as GDM. The model demonstrated an increased prevalence of GDM in spring and summer (odds ratio: 1.59, 95% confidence interval: 1.13-2.24; odds ratio: 1.59, 95% confidence interval: 1.14-2.23, respectively) compared to winter. For the glucose level variation, the model demonstrated an increase of 2.56 mg/dL glucose in the 50-g glucose challenge test in summer compared to winter. In glucose challenge test-positive pregnancies, the season also had an effect on the results of the 100-g 1-h, 2-h, and 3-h oral glucose tolerance tests, but no effect on the 100-g fasting oral glucose tolerance tests.GDM prevalence in Taiwan presents seasonal variation, with the highest risk during spring and summer due to post-glucose load level variations. These findings could serve as reference data for countries in Southeast Asia or areas with a similar climate.

Special considerations for vitamin D in the south Asian population in the UK

The human requirement for vitamin D is achieved primarily through the synthesis of this prehormone in the skin during exposure to ultraviolet B (UVB) radiation, with only a minor contribution from the diet, year round. Achieving optimal vitamin D status is therefore largely dependent upon adequate exposure of the skin to sunlight, however, the length of exposure required varies with latitude and season, and is also dependent upon skin pigmentation, with darker skin requiring greater exposure than fair skin due to the protective effects of melanin against UVB radiation. In northern European latitudes, where UVB radiation between the months of October and March is of insufficient intensity for the synthesis of vitamin D via this route, vitamin D deficiency is a public health concern, particularly for south Asian diaspora and other dark-skinned ethnic minority communities. The consequences of vitamin D deficiency include poor bone health, including rickets and osteomalacia. In addition, there is increasing awareness of an important role for vitamin D in the development and progression of chronic diseases, including type 2 diabetes, which is prevalent in south Asian populations. The aim of this review is to examine some of the most recent reports of vitamin D status in south Asian diaspora communities, and to explore its impact on bone health. In addition, we will examine the putative association between type 2 diabetes and vitamin D deficiency in south Asian populations and the current guidelines for treatment of vitamin D deficiency of south Asians in primary care settings.

Clinical Recommendations for the Use of Islet Cell Autoantibodies to Distinguish Autoimmune and Non-Autoimmune Gestational Diabetes

Gestational diabetes mellitus (GDM) is defined as carbohydrate intolerance that begins or is first recognized during pregnancy. The prevalence of GDM is highly variable, depending on the population studied, and reflects the underlying pattern of diabetes in the population. GDM manifests by the second half of pregnancy and disappears following delivery in most cases, but is associated with the risk of subsequent diabetes development. Normal pregnancy induces carbohydrate intolerance to favor the availability of nutrients for the fetus, which is compensated by increased insulin secretion from the maternal pancreas. Pregnancy shares similarities with adiposity in metabolism to save energy, and both conditions favor the development of insulin resistance (IR) and low-grade inflammation. A highly complicated network of modified regulatory mechanisms may primarily affect carbohydrate metabolism by promoting autoimmune reactions to pancreatic β cells and affecting insulin function. As a result, diabetes development during pregnancy is facilitated. Depending on a pregnant woman's genetic susceptibility to diabetes, autoimmune mechanisms or IR are fundamental to the development autoimmune or non-autoimmune GDM, respectively. Pregnancy may facilitate the identification of women at risk of developing diabetes later in life; autoimmune and non-autoimmune GDM may be early markers of the risk of future type 1 and type 2 diabetes, respectively. The most convenient and efficient way to discriminate GDM types is to assess pancreatic β-cell autoantibodies along with diagnosing diabetes in pregnancy.

Effects of initial body mass index on development of gestational diabetes in a rural Sri Lankan population: A case-control study

AIM

High pre-pregnancy body mass index (BMI) and excessive pregnancy weight gain lead to higher incidence of gestational diabetes mellitus (GDM). Aim of the study was to assess the effects of initial BMI and pregnancy weight gain on development of GDM in a rural Sri Lankan population. It was also hypothesized that these effects could be more pronounced in shorter mothers.

METHODS

A case-control study was conducted at two rural hospitals in Sri Lanka. A case was defined as a pregnant mother admitted for the completion of pregnancy and diagnosed to have GDM (n=99). A similar group of mothers without GDM were recruited as controls (n=336). Data were collected through health records and direct interviews.

RESULTS

Mean age of GDM and non-GDM mothers were 32.8 years 28.1 years, respectively. High pre-pregnancy BMI was a significant risk for GDM, with a rising trend with increasing BMI. In contrast to underweight mothers, the risk increases from normal weight [odds ratio (OR)=6.6, 95% confidence interval (CI) 2.2-19.4, p<0.01], overweight (OR=17.1, 95% CI 5.8-49.9, p<0.01) and to obese (OR=32.4, 95% CI 10.0-104.5, p<0.01). There was no significant difference in weight gain across mother's height groups. Height or leg length did not show an association with GDM. Family history of diabetes and past GDM were associated with GDM. GDM mothers had higher likelihood for cesarian deliveries, and babies with higher birth weight.

CONCLUSION

The pre-pregnancy BMI was the most important modifiable risk factor for GDM, and it should be the main preventive measure.

Diabetes in low-resourced countries

Maternal and newborn health poses one of the greatest health challenges in the developing world. Many low-income countries are now experiencing a demographic and epidemiological transition and changing of lifestyles. Thus, apparent "Western" diseases such as diabetes and obesity have been reaching the Third World countries. There is a paucity of reliable data on diabetes in pregnancy in many low-income countries. Adequate information about maternal and perinatal mortality and morbidity as a consequence of diabetes in pregnancy is scarce. This chapter presents evidence of the magnitude and impact of diabetes in pregnancy. Additionally, we discuss interventions in screening and managing diabetes in pregnancy in these specific patient populations.

Associations of circulating calcium and 25-hydroxyvitamin D with glucose metabolism in pregnancy: a cross-sectional study in European and South Asian women

BACKGROUND

Vitamin D deficiency is thought to impair insulin action and glucose metabolism; however, previous studies have not examined ethnic differences or the influence of calcium and parathyroid hormone. We investigated this in a cohort of predominantly white European and south Asian women during pregnancy.

METHODS

In this cross-sectional study from an urban population in northern England (53.8°N), 1467 women were recruited when undergoing glucose tolerance testing (75 g oral glucose tolerance test) at 26 weeks' gestation.

RESULTS

Gestational diabetes mellitus (GDM) was diagnosed in 137 women (9.3%). Median 25-hydroxyvitamin D concentration for the study population was 9.3 ng/mL (interquartile range 5.2, 16.9) and was higher in European [15.2 ng/mL (10.7, 23.5)] than in south Asian women [5.9 ng/mL (3.9, 9.4), P < .001]. After appropriate adjustment for confounders, 25-hydroxyvitamin D showed a weak inverse association with fasting plasma glucose (FPG; mean difference 1.0% per 1 SD; the ratio of geometric means (RGM) 0.99, 95% confidence interval (CI) 0.98, 1.00), and PTH was weakly associated with FPG (RGM 1.01, 95% CI 1.00, 1.02), but neither was associated with fasting insulin, postchallenge glucose, or GDM. Serum calcium (albumin adjusted) was strongly associated with fasting insulin (RGM 1.06; 95% CI 1.03, 1.08), postchallenge glucose (RGM 1.03, 95% CI 1.01, 1.04), and GDM (odds ratio 1.33, 95% CI 1.06, 1.66) but not with FPG. Associations were similar in European and south Asian women.

CONCLUSIONS

These findings do not indicate any important association between vitamin D status and glucose tolerance in pregnancy. Relationships between circulating calcium and glucose metabolism warrant further investigation.

The impact of ethnicity on glucose homeostasis after gestational diabetes mellitus

The objective of this study was to examine measures of insulin resistance and beta cell function in relation to ethnicity and the development of diabetes after gestational diabetes mellitus (GDM). Glucose homeostasis was assessed during a 75 g oral glucose tolerance test 1-2 years after delivery in 456 women with previous GDM (362 European, 94 non-European; including 41 Arab and 43 Asian women) and 133 control women. Insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR). The insulinogenic index (I/G30) and the disposition index [(I/G30)/HOMA-IR] were used to quantify insulin secretion. Women developing diabetes after GDM were characterized by increased HOMA-IR [p = 0.010, adjusted for body mass index (BMI)], whereas the disposition index was decreased in all women with previous GDM irrespective of glucose tolerance, most pronounced in the presence of diabetes (BMI-adjusted p = 1 × 10(-5)). Non-European origin was associated with increased HOMA-IR (p = 0.001 vs. European), strengthened by adjustment for BMI in Asian women (p = 0.046 vs. p = 0.016), but eradicated among Arab women (p = 0.004 vs. p = 0.65). Non-European women exhibited an increased frequency of diabetes after GDM (17 % vs. European 4 %, p = 2 × 10(-5)). In addition to BMI, non-European and Asian origin was associated with the development of diabetes after GDM in a multivariate logistic regression analysis, whereas Arab origin was not. Our results highlight the importance of preventive measures to ensure a healthy lifestyle in women with GDM, particularly in high-risk ethnic groups.

Maternal/fetal determinants of insulin resistance in women during pregnancy and in offspring over life

Insulin resistance is a component of the pathophysiology of both type 2 diabetes and gestational diabetes mellitus (GDM), but is also characteristic of normal glycemic physiology during pregnancy. In recent years, many studies have tried to understand determinants of insulin resistance in normal pregnancy and GDM, revealing that the placenta is capable of secreting many cytokines and hormones, classically considered as adipokines. More specifically, it appears that leptin and TNFα could be implicated in gestational insulin resistance and GDM pathophysiology. In addition, the maternal metabolic milieu was also identified as a key determinant of later insulin resistance in offspring, a phenomenon often described as 'fetal programming'. This article reviews the established risk factors and the more novel suspected biomarkers involved in maternal insulin resistance during pregnancy as well as the maternal and early life determinants of insulin resistance in offspring later in their life. We are also highlighting recent reports of the potential mechanisms involved in 'programming' of insulin resistance such as epigenetic modulation.

Maternal racial origin and adverse pregnancy outcome: a cohort study

OBJECTIVE

To examine the association between maternal racial origin and a wide range of adverse pregnancy outcomes after adjustment for confounding factors in obstetric history and maternal characteristics.

METHODS

This was a retrospective study in women with singleton pregnancies attending their first routine hospital visit at 11 + 0 to 13 + 6 weeks of gestation. Data on maternal characteristics, and medical and obstetric history were collected and pregnancy outcomes ascertained. Regression analysis was performed to examine the association between racial origin and adverse pregnancy outcomes including pre-eclampsia (PE), gestational hypertension (GH), gestational diabetes mellitus (GDM), preterm delivery (PTD), small-for-gestational age (SGA), large-for-gestational age (LGA), miscarriage, stillbirth and elective and emergency Cesarean section (CS).

RESULTS

The study population included 76 158 singleton pregnancies with a live fetus at 11 + 0 to 13 + 6 weeks. In addition to maternal characteristics and obstetric history, Afro-Caribbean racial origin was associated with increased risk for miscarriage, stillbirth, PE, GH, spontaneous PTD, GDM, SGA and CS. In women of South Asian racial origin there was increased risk for PE, GDM, SGA and CS, and East Asian race contributed to the prediction of GDM and SGA.

CONCLUSION

Maternal racial origin should be combined with other maternal characteristics and obstetric history when calculating an individualized adjusted risk for adverse pregnancy outcome.

Failure to increase insulin secretory capacity during pregnancy-induced insulin resistance is associated with ethnicity and gestational diabetes

OBJECTIVE

To assess changes in insulin resistance and β-cell function in a multiethnic cohort of women in Oslo, Norway, from early to 28 weeks' gestation and 3 months post partum and relate the findings to gestational diabetes mellitus (GDM).

METHOD

Population-based cohort study of 695 healthy pregnant women from Western Europe (41%), South Asia (25%), Middle East (15%), East Asia (6%) and elsewhere (13%). Blood samples and demographics were recorded at mean 15 (V1) and 28 (V2) weeks' gestation and 3 months post partum (V3). Universal screening was by 75 g oral glucose tolerance test at V2, GDM with modified IADPSG criteria (no 1-h measurement): fasting plasma glucose (PG) ≥5.1 or 2-h PG ≥8.5 mmol/l. Homeostatic model assessment (HOMA)-β (β-cell function) and HOMA-IR (insulin resistance) were calculated from fasting glucose and C-peptide.

RESULT

Characteristics were comparable across ethnic groups, except age (South Asians: younger, P<0.001) and prepregnant BMI (East Asians: lower, P=0.040). East and South Asians were more insulin resistant than Western Europeans at V1. From V1 to V2, the increase in insulin resistance was similar across the ethnic groups, but the increase in β-cell function was significantly lower for the East and South Asians compared with Western Europeans. GDM women compared with non-GDM women were more insulin resistant at V1; from V1 to V2, their β-cell function increased significantly less and the percentage increase in β-cell function did not match the change in insulin resistance.

CONCLUSION

Pregnant women from East Asia and South Asia were more insulin resistant and showed poorer HOMA-β-cell function than Western Europeans.

Racial/ethnic disparities in the prevalence of gestational diabetes mellitus by BMI

OBJECTIVE

To examine whether the association between gestational diabetes mellitus (GDM) and BMI category varies by racial/ethnic group.

RESEARCH DESIGN AND METHODS

In a cohort of 123,040 women without recognized pregravid diabetes who delivered babies between 1995 and 2006 at Kaiser Permanente of Northern California, we examined racial/ethnic disparities in the prevalence of GDM by BMI category and the population-attributable risk (PAR) associated with overweight/obesity.

RESULTS

Among all racial/ethnic groups, the age-adjusted prevalence of GDM increased with increasing BMI (kg/m(2)) category. However, Asian and Filipina women had a prevalence of GDM of 9.9 and 8.5%, respectively, at a BMI of 22.0-24.9 kg/m(2), whereas in Hispanic, non-Hispanic white, and African American women, the prevalence of GDM was >8.0% at a higher BMI, such as 28-30, 34-36, and ≥37 kg/m(2), respectively. The estimated PARs suggest that the percentage of GDM that could be prevented if all pregnant women were of normal weight (BMI <25.0 kg/m(2)) ranging from 65% for African American women to only 23% among Asian women.

CONCLUSIONS

Clinicians should be aware that the BMI thresholds for increased risk of GDM varies by racial/ethnic group and that the risk is high even at relatively low BMI cutoffs in Asian and Filipina women. Asian women may benefit from different prevention strategies in addition to weight management.

Consequences of gestational diabetes in an urban hospital in Viet Nam: a prospective cohort study

BACKGROUND

Gestational diabetes mellitus (GDM) is increasing and is a risk for type 2 diabetes. Evidence supporting screening comes mostly from high-income countries. We aimed to determine prevalence and outcomes in urban Viet Nam. We compared the proposed International Association of the Diabetes and Pregnancy Study Groups (IADPSG) criterion, requiring one positive value on the 75-g glucose tolerance test, to the 2010 American Diabetes Association (ADA) criterion, requiring two positive values.

METHODS AND FINDINGS

We conducted a prospective cohort study in Ho Chi Minh City, Viet Nam. Study participants were 2,772 women undergoing routine prenatal care who underwent a 75-g glucose tolerance test and interview around 28 (range 24-32) wk. GDM diagnosed by the ADA criterion was treated by local protocol. Women with GDM by the IADPSG criterion but not the ADA criterion were termed "borderline" and received standard care. 2,702 women (97.5% of cohort) were followed until discharge after delivery. GDM was diagnosed in 164 participants (6.1%) by the ADA criterion, 550 (20.3%) by the IADPSG criterion. Mean body mass index was 20.45 kg/m(2) in women with out GDM, 21.10 in women with borderline GDM, and 21.81 in women with GDM, p<0.001. Women with GDM and borderline GDM were more likely to deliver preterm, with adjusted odds ratios (aORs) of 1.49 (95% CI 1.16-1.91) and 1.52 (1.03-2.24), respectively. They were more likely to have clinical neonatal hypoglycaemia, aORs of 4.94 (3.41-7.14) and 3.34 (1.41-7.89), respectively. For large for gestational age, the aORs were 1.16 (0.93-1.45) and 1.31 (0.96-1.79), respectively. There was no significant difference in large for gestational age, death, severe birth trauma, or maternal morbidity between the groups. Women with GDM underwent more labour inductions, aOR 1.51 (1.08-2.11).

CONCLUSIONS

Choice of criterion greatly affects GDM prevalence in Viet Nam. Women with GDM by the IADPSG criterion were at risk of preterm delivery and neonatal hypoglycaemia, although this criterion resulted in 20% of pregnant women being positive for GDM. The ability to cope with such a large number of cases and prevent associated adverse outcomes needs to be demonstrated before recommending widespread screening. Please see later in the article for the Editors' Summary.

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.

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.

The association between body mass index and gestational diabetes mellitus varies by race/ethnicity

We examined body mass index (BMI) as a screening tool for gestational diabetes (GDM) and its sensitivity among different racial/ethnic groups. In a retrospective cohort study of 24,324 pregnant women at University of California, San Francisco, BMI was explored as a screening tool for GDM and was stratified by race/ethnicity. Sensitivity and specificity were examined using chi-square test and receiver-operator characteristic curves. BMI of ≥25.0 kg/m (2) as a screening threshold identified GDM in >76% of African-Americans, 58% of Latinas, and 46% of Caucasians, but only 25% of Asians ( P < 0.001). Controlling for confounders and comparing to a BMI of ≤25, African-Americans had the greatest increased risk of GDM (adjusted odds ratio [AOR] 5.1, 95% confidence interval [CI]: 3.0 to 8.5), followed by Caucasians (AOR 3.6, 95% CI: 2.7 to 4.8), Latinas (AOR 2.7, 95% CI: 1.9 to 3.8), and Asians (AOR 2.3, 95% CI: 1.8 to 3.0). BMI's screening characteristics to predict GDM varied by race/ethnicity. BMI can be used to counsel regarding the risk of developing GDM, but alone it is not a good screening tool.

Fetal umbilical arterial and venous Doppler measurements in gestational diabetic and nondiabetic pregnancies near term

OBJECTIVE

To compare Doppler measurements of umbilical arteries (UAs) and veins (UV) in diabetic and nondiabetic pregnancies near term.

METHODS

Consecutive patients with gestational diabetes mellitus (GDM) were prospectively recruited from a regional obstetric service over an 18-month period. Doppler assessment of the UA and UV done within 10 days from delivery were used for analysis. Similar measurements were performed in a control group of nondiabetic nonhypertensive patients near term.

RESULTS

All of the Doppler waveform patterns were within normal in the cohort of 140 patients (GDM 84, normal 62). The mean PI values for the UA and the mean total umbilical venous flow (TUVF) and TUVF per unit birth weight did not differ significantly between diabetic and nondiabetic pregnancies. Large-for-gestational-age fetuses showed higher TUVF than normal size fetuses, but the TUVF per unit birth weight was higher for small-gestational-age fetuses. These differences were independent of their diabetic status.

CONCLUSION

Umbilical arterial and venous Doppler measurements near term were unable to distinguish between diabetic and nondiabetic pregnancies. Umbilical venous flow volume was apparently more sensitive to the size of the fetus than to the maternal diabetic state.

International migration and adverse birth outcomes: role of ethnicity, region of origin and destination

BACKGROUND

The literature on international migration and birth outcomes shows mixed results. This study examined whether low birth weight (LBW) and preterm birth differed between non-migrants and migrant subgroups, defined by race/ethnicity and world region of origin and destination.

METHODS

A systematic review and meta-regression analyses were conducted using three-level logistic models to account for the heterogeneity between studies and between subgroups within studies.

RESULTS

Twenty-four studies, involving more than 30 million singleton births, met the inclusion criteria. Compared with US-born black women, black migrant women were at lower odds of delivering LBW and preterm birth babies. Hispanic migrants also exhibited lower odds for these outcomes, but Asian and white migrants did not. Sub-Saharan African and Latin-American and Caribbean women were at higher odds of delivering LBW babies in Europe but not in the USA and south-central Asians were at higher odds in both continents, compared with the native-born populations.

CONCLUSIONS

The association between migration and adverse birth outcomes varies by migrant subgroup and it is sensitive to the definition of the migrant and reference groups.

Comparison the Carpenter and Coustan thresholds with the new thresholds obtained from Thai pregnant women for the diagnosis of gestational diabetes

AIMS

To determine the threshold of plasma glucose levels calculated from the mean+2SDs for diagnosing gestational diabetes mellitus (GDM) in Thai women.

METHODS

Thai pregnant women without pre-existing diabetes were invited into the study. A 100-g oral glucose tolerance test (OGTT) was performed in all participants during their second or third trimesters, regardless of the results of 50-g glucose challenge test.

RESULTS

Seven hundred and ninety seven women with singleton pregnancy participated in the study. The distribution of 1-, 2-, and 3-h plasma glucose levels of the 100-g OGTT was Gaussian. The rounded cut-off point values calculated from the mean+2SDs were 90, 195, 170, and 155 mg/dl, respectively for fasting, 1-, 2-, and 3-h plasma glucose. With the Carpenter and Coustan thresholds, 52 women (6.5%, 95%CI 4.9-8.5%) were diagnosed as GDM. Of these, when tested with the new thresholds, 30 had normal glucose tolerance and 22 were diagnosed as GDM.

CONCLUSION

By using mean+2SDs of plasma glucose levels of the 100-g OGTT as the threshold for diagnosing GDM, the thresholds at 1, 2, and 3h obtained from Thai women were 15 mg/dl higher than those of the Carpenter and Coustan thresholds.

Maternal vitamin D deficiency, ethnicity and gestational diabetes

AIMS

Vitamin D deficiency has been linked to impaired glucose metabolism. We determined whether serum 25-hydroxyvitamin D (25OHD) is associated with glucose metabolism in pregnant women and the effect of ethnicity on this relationship.

METHODS

We analysed serum 25OHD concentrations in 307 pregnant women attending a metropolitan obstetric clinic between October 2003 and May 2005. Measurements from 264 of the women were taken at the time of glucose tolerance testing at mid-gestation, a population therefore at increased risk for gestational diabetes. Pearson correlation analysis was used to test for univariate linear relationships between the natural log of serum 25OHD (ln-25OHD) and other variables. Multiple regression analysis was used to adjust for confounding factors.

RESULTS

Mean serum 25OHD concentration was 53.8 +/- 23.9 nmol/l (sd). Ln-25OHD was negatively correlated with serum parathyroid hormone as expected (r -0.24, confidence intervals -0.35 to -0.12). Ln-25OHD was also negatively correlated with fasting plasma glucose (r-0.20, -0.31 to -0.08), fasting insulin (r -0.20, -0.31 to -0.08) and insulin resistance as calculated by homeostasis model assessment (r -0.21, -0.32 to -0.09). The association between fasting glucose and log-transformed 25OHD concentration was of borderline significance after accounting for ethnicity, age and body mass index in multivariate analyses (-0.13, -0.26 to 0.01). The odds ratio of gestational diabetes in women with 25OHD < 50 nmol/l did not reach statistical significance (1.92, 95% confidence interval 0.89-4.17).

CONCLUSIONS

Maternal 25OHD concentrations are inversely related to fasting glucose, although further studies are required to establish whether this is independent of the effects of ethnic background.

Influence of acute upper respiratory tract infection on the absorption of inhaled insulin using the AERx insulin Diabetes Management System

AIMS

To assess the effects due to an uncomplicated acute upper respiratory tract infection (URTI) on the pharmacokinetics and glucose response of insulin when delivered by oral pulmonary absorption.

METHODS

Normally healthy adult men (n = 11) and women (n = 9) received a single dose of inhaled human insulin, equivalent to approximately 6 IU subcutaneous, using the AERx insulin Diabetes Management System (iDMS), during and following recovery from an URTI. The first dose was administered with ongoing symptoms of < 3 days' duration, the second dose following recovery, and within 3 weeks of the first. Blood sampling for determination of insulin pharmacokinetics (serum AUC(0-6 h), AUC(0-8), C(max),t(max), t(1/2), MRT) and glucose response (plasma AOC(0-6 h)) was performed from 15 min predose to 6 h postdose.

RESULTS

Insulin pharmacokinetics were not different for subjects during and following recovery from URTI [e.g. URTI: no URTI ratio in serum AUC(0-6 h) = 0.92 (95% confidence interval 0.81, 1.05)]; this was reflected by a similar glucose response. Inhaled insulin delivered by AERx iDMS was well tolerated by all subjects; no significant changes were observed in pulmonary function tests. No safety concerns arising from the mode of insulin administration were raised by either dose.

CONCLUSIONS

The results suggest that insulin can be administered via AERx iDMS to nondiabetic subjects experiencing a URTI without any statistically significant changes in insulin pharmacokinetics or pharmacodynamics, and that the necessity for dose adjustments will not differ from subjects with an acute URTI who are receiving subcutaneous insulin.

Gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is defined as glucose intolerance of various degrees that is first detected during pregnancy. GDM is detected through the screening of pregnant women for clinical risk factors and, among at-risk women, testing for abnormal glucose tolerance that is usually, but not invariably, mild and asymptomatic. GDM appears to result from the same broad spectrum of physiological and genetic abnormalities that characterize diabetes outside of pregnancy. Indeed, women with GDM are at high risk for having or developing diabetes when they are not pregnant. Thus, GDM provides a unique opportunity to study the early pathogenesis of diabetes and to develop interventions to prevent the disease.

Gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is defined as glucose intolerance of various degrees that is first detected during pregnancy. GDM is detected through the screening of pregnant women for clinical risk factors and, among at-risk women, testing for abnormal glucose tolerance that is usually, but not invariably, mild and asymptomatic. GDM appears to result from the same broad spectrum of physiological and genetic abnormalities that characterize diabetes outside of pregnancy. Indeed, women with GDM are at high risk for having or developing diabetes when they are not pregnant. Thus, GDM provides a unique opportunity to study the early pathogenesis of diabetes and to develop interventions to prevent the disease.

A population-based screening for gestational diabetes mellitus in non-diabetic women in Bahrain

BACKGROUND

Maternal hyperglycemia is considered a risk factor for fetal morbidity. Since there is a high prevalence of diabetes mellitus among the population of Bahrain, we conducted a prospective population-based study of gestational diabetes mellitus (GDM) in non-diabetic pregnant women.

SUBJECTS AND METHODS

All non-diabetic pregnant women attending antenatal clinics during January 2001 to December 2002 (n=10,495) were screened for GDM during the 24th to 28th weeks of gestation. All positive subjects based on a 50-g glucose challenge test (GCT) were further evaluated by a diagnostic 75-g oral glucose tolerance test (OGTT). The birth weight of the child and post-delivery insulin resistance were monitored. The homeostasis model of insulin resistance (HOMA-IR) was used to assess insulin resistance.

RESULTS

Of 10,495 non-diabetic pregnant women screened, 32.8% (n=3443) had plasma glucose > or = 7.8 mmol/L (140 mg/dL) in the GCT. The 75-g OGTT found a prevalence of GDM of 13.5%. There were twice as many Bahrainis as expatriates. Of children born to women with GDM, 6.5% had a birth weight > 4000 g. Post-delivery evaluation of insulin resistance indicated that 33% of women with GDM had a HOMA-IR value > 2.

CONCLUSION

The population of Bahrain is a high-risk ethnic group for GDM. The association of insulin resistance in the post-gravid state with GDM among 33% of the study population suggests that insulin resistance, the possible cause of the pathophysiological mechanism underlying the development of gestational diabetes, continues in the post gravid state.

Epidemiology of gestational diabetes mellitus and its association with Type 2 diabetes

Gestational diabetes (GDM) is defined as carbohydrate intolerance that begins or is first recognized during pregnancy. Although it is a well-known cause of pregnancy complications, its epidemiology has not been studied systematically. Our aim was to review the recent data on the epidemiology of GDM, and to describe the close relationship of GDM to prediabetic states, in addition to the risk of future deterioration in insulin resistance and development of overt Type 2 diabetes. We found that differences in screening programmes and diagnostic criteria make it difficult to compare frequencies of GDM among various populations. Nevertheless, ethnicity has been proven to be an independent risk factor for GDM, which varies in prevalence in direct proportion to the prevalence of Type 2 diabetes in a given population or ethnic group. There are several identifiable predisposing factors for GDM, and in the absence of risk factors, the incidence of GDM is low. Therefore, some authors suggest that selective screening may be cost-effective. Importantly, women with an early diagnosis of GDM, in the first half of pregnancy, represent a high-risk subgroup, with an increased incidence of obstetric complications, recurrent GDM in subsequent pregnancies, and future development of Type 2 diabetes. Other factors that place women with GDM at increased risk of Type 2 diabetes are obesity and need for insulin for glycaemic control. Furthermore, hypertensive disorders in pregnancy and afterwards may be more prevalent in women with GDM. We conclude that the epidemiological data suggest an association between several high-risk prediabetic states, GDM, and Type 2 diabetes. Insulin resistance is suggested as a pathogenic linkage. It is possible that improving insulin sensitivity with diet, exercise and drugs such as metformin may reduce the risk of diabetes in individuals at high risk, such as women with polycystic ovary syndrome, impaired glucose tolerance, and a history of GDM. Large controlled studies are needed to clarify this issue and to develop appropriate diabetic prevention strategies that address the potentially modifiable risk factors.

Incidence of fetal macrosomia and birth complications in Chinese immigrant women

OBJECTIVE

To compare rates of fetal macrosomia (birthweight > 4000 g) and birth complications in both Chinese women immigrants and Caucasian women for two time periods: 1992 and 1999-2000.

POPULATION

Chinese women immigrants and Caucasian women attending the Royal North Shore Hospital and Hornsby Ku-Ring-Gai Hospital in Sydney's northern health region.

METHODS

Data used were extracted from the Northern Suburbs Area Health Service OBSTET database. Significance of trends were assessed using chi2 test.

RESULTS

The results show a rise in macrosomic babies born to Chinese immigrants from 4% of total Chinese births in 1992 to 9.8% in 1999-2000 (P = 0.02). There was no significant difference in the rate of macrosomia among Caucasian women with respective rates of 11 and 14% for the same periods. The incidence of post-partum haemorrhage increased significantly in both Chinese immigrants and Caucasian women (P < 0.001).

CONCLUSION

Australia has a multicultural population and yet the normal ranges defined for many obstetric investigations do not adjust for ethnicity. The application of values derived from a Caucasian population to other ethnic populations may be inappropriate and conceal important pathologies.