Weight gain adequacy and pregnancy outcomes in gestational diabetes: a meta-analysis.

The Institute of Medicine updated guidelines for gestational weight gain in 2009, with no special recommendations for gestational diabetes. Our objectives were to describe the prevalence of weight gain adequacy and their association with adverse pregnancy outcomes in gestational diabetes. We searched MEDLINE, EMBASE, COCHRANE and SCOPUS. We calculated the pooled prevalence of gain adequacy and relative risks for pregnancy outcomes within Institute of Medicine categories. Thirty-three studies/abstracts (88,599 women) were included. Thirty-one studies provided data on the prevalence of weight gain adequacy; it was adequate in 34% (95% CI: 29-39%) of women, insufficient in 30% (95% CI: 27-34%) and excessive in 37% (95% CI: 33-41%). Excessive gain was associated with increased risks of pharmacological treatment, hypertensive disorders of pregnancy, caesarean section, large for gestational age and macrosomic babies, compared to adequate or non-excessive gain. Weight gain below the guidance had a protective effect on large babies (RR: 0.71; 95% CI: 0.56-0.90) and macrosomia (RR 0.57; 95% CI 0.40-0.83), and did not increase the risk of small babies (RR 1.40; 95% CI 0.86-2.27). Less than recommended weight gain would be beneficial, while effective prevention of excessive gain is of utmost importance, in gestational diabetes pregnancies. Nevertheless, no ideal range for weight gain could be established.

Gestational diabetes mellitus diagnosed with a 2-h 75-g oral glucose tolerance test and adverse pregnancy outcomes.

OBJECTIVE: To evaluate American Diabetes Association (ADA) and World Health Organization (WHO) diagnostic criteria for gestational diabetes mellitus (GDM) against pregnancy outcomes. RESEARCH DESIGN AND METHODS: This cohort study consecutively enrolled Brazilian adult women attending general prenatal clinics. All women were requested to undertake a standardized 2-h 75-g oral glucose tolerance test (OGTT) between their estimated 24th and 28th gestational weeks and were then followed to delivery. New ADA criteria for GDM require two plasma glucose values > or = 5.3 mmol/l (fasting), > or = 10 mmol/l (1 h), and > or = 8.6 mmol/l (2 h). WHO criteria require a plasma glucose > or = 7.0 mmol/l (fasting) or > or = 7.8 mmol/l (2 h). Individuals with hyperglycemia indicative of diabetes outside of pregnancy were excluded. RESULTS: Among the 4,977 women studied, 2.4% (95% CI 2.0-2.9) presented with GDM by ADA criteria and 7.2% (6.5-7.9) by WHO criteria. After adjustment for the effects of age, obesity, and other risk factors, GDM by ADA criteria predicted an increased risk of macrosomia (RR 1.29, 95% CI 0.73-2.18), preeclampsia (2.28, 1.22-4.16), and perinatal death (3.10, 1.42-6.47). Similarly, GDM by WHO criteria predicted increased risk for macrosomia (1.45, 1.06-1.95), preeclampsia (1.94, 1.22-3.03), and perinatal death (1.59, 0.86-2.90). Of women positive by WHO criteria, 260 (73%) were negative by ADA criteria. Conversely, 22 (18%) women positive by ADA criteria were negative by WHO criteria. CONCLUSIONS: GDM based on a 2-h 75-g OGTT defined by either WHO or ADA criteria predicts adverse pregnancy outcomes.

Prevalence of gestational diabetes mellitus--do the new WHO criteria make a difference? Brazilian Gestational Diabetes Study Group.

AIMS: To describe the prevalence of gestational diabetes mellitus (GDM) according to the 1998 WHO provisional recommendations and compare it to that found with previous 1985 WHO criteria. METHODS: A total of 5564 consecutive women aged 20 years or more without diagnosis of diabetes mellitus outside of pregnancy in general prenatal care clinics of the National Health Service in 6 state capitals of Brazil, between their 20th and 28th gestational weeks were enrolled. RESULTS: Of the 5004 women who completed a 75-g oral glucose tolerance test, 379 (7.6%, 95% confidence interval (CI) 6.9% to 8.4%) had GDM by the 1998 criteria (fasting glucose > or = 7.0 mmol/l or 2 h glucose > or = 7.8 mmol/l). Of these 379 cases, only 21 (5.5%) had hyperglycaemia in the range considered diabetes mellitus outside pregnancy (fasting glucose > or = 7.0 mmol/l or 2 h glucose > or = 11.1 mmol/l); the remaining 358 (94.5%) had hyperglycaemia in the impaired glucose tolerance range (fasting glucose < 7.0 and 2 h glucose > or = 7.8 mmol/l and < 11.1 mmol/l). Using the 1985 criteria (fasting or 2 h glucose > or = 7.8 mmol/l), 378 cases of GDM were found, 15 in the diabetes range and 363 in the impaired glucose tolerance range. CONCLUSIONS: Prevalence of GDM is minimally altered by the new WHO definition. Although GDM is a common condition, the vast majority of the cases have hyperglycaemia in the range considered impaired glucose tolerance outside pregnancy.

Fasting plasma glucose is a useful test for the detection of gestational diabetes. Brazilian Study of Gestational Diabetes (EBDG) Working Group.

OBJECTIVE: To evaluate fasting plasma glucose as a screening test for states of gestational diabetes. RESEARCH DESIGN AND METHODS: Baseline data of a cohort conducted in general prenatal care units in Brazil, enrolling 5,579 women aged > or = 20 years with gestational ages of 24-28 weeks at the time of testing and no previous diagnosis of diabetes. A standardized 2-h 75-g oral glucose tolerance test was performed in 5,010 women. Gestational diabetes and its subcategories--diabetes and impaired glucose tolerance--were defined according to the 1994 World Health Organization panel recommendations. We evaluated screening properties of calculated sensitivity and specificity for fasting plasma glucose with receiver operator characteristic curves. RESULTS: For detection of the subcategory diabetes, a fasting plasma glucose of 89 mg/dl jointly maximizes sensitivity (88%) and specificity (78%), identifying 22% of the women as test-positive. For detection of impaired glucose tolerance, a value of 85 mg/dl jointly maximizes sensitivity and specificity (68%), identifying as test-positive 35% of the women. Lowering the cut point to 81 mg/dl increases sensitivity to 81%, but decreases specificity to 54%, labeling as test-positive 49% of the women. CONCLUSIONS: Fasting plasma glucose is a useful test for the screening of both subcategories of gestational diabetes, a threshold of 85 mg/dl being an acceptable option. Effective screening for the subcategory diabetes can be achieved using a cut point of 89 mg/dl. If greater emphasis is placed on the detection of impaired glucose tolerance, a lower value, 81 mg/dl, may be needed.

Waist circumference and waist-to-hip ratio are related to gestational glucose tolerance.

OBJECTIVE: To evaluate the relationship of central fat distribution with gestational glucose tolerance during the usual time for screening gestational diabetes. RESEARCH DESIGN AND METHODS: This cross-sectional study investigated 1,113 consecutive women, > or = 20 years old, pregnant for approximately 21 to 28 weeks, without history of previous diabetes outside pregnancy, who attended two general prenatal care units in Porto Alegre, Brazil, from 1991 to 1993. Weight, height, waist and hip circumferences, and skinfolds were measured, and a 2-h, 75-g glucose tolerance test was performed. Data were analyzed using multiple linear regression models. RESULTS: Waist-to-hip ratio (WHR) and waist circumference were independently associated with higher 2-h glycemia. Glycemic level was 0.11 and 0.13 mmol/l greater for each standard deviation increase in WHR (0.06) and waist circumference (8.0 cm), respectively (P < 0.02). Restricting analyses to the subset of women with uterine height < or = 26 cm improved the association (0.13 and 0.19 mmol/l, respectively, P < 0.02); differences of 0.22 and 0.19 mmol/l were observed for 1 SD changes in the sum of skinfold thicknesses (24.7 mm) and in age (5.5 years), respectively. CONCLUSIONS: Central fat distribution measured in pregnancy is an independent predictor of gestational glucose intolerance. This finding supports the concept that NIDDM and gestational diabetes are parts of the same disease, differing basically in their moment of detection. The usefulness of these anthropometric measurements in identifying pregnant women at high risk of having gestational glucose intolerance merits further investigation.

Variation in glucose tolerance with ambient temperature.

Ambient temperature may affect venous glucose concentration after glucose tolerance tests. We analysed 1030 standardised 75 g tests. Although mean fasting values did not differ, post-load values did: adjusted mean 2 h glucose concentration was 1.03 mmol/L lower at lower (5-14 degrees C) than at higher (25-31 degrees C) temperatures (p < 0.001). The occurrence of abnormal glucose tolerance doubled on warmer days. The diagnostic accuracy of the glucose tolerance test showed clinically significant temperature-associated variation. These variations, if confirmed, call for temperature standardisation during glucose tolerance testing and/or alternative strategies for use when standardisation is not feasible.