Higher Thyroid fT3-to-fT4 Ratio Is Associated with Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes.

Aim: To determine the association between thyroid function and the risk of developing gestational diabetes mellitus (GDM) and adverse pregnancy outcomes. Methods: This case−control study was a sub-analysis of the BEDIP-N study, in which 199 GDM women were matched for age and body mass index with 398 controls. Thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and thyroid peroxidase (TPO) antibodies were measured at 6−14 weeks and 26−28 weeks during pregnancy. TSH and fT4 were also measured in early postpartum in GDM women. Results: The fT3-to-fT4 ratio at 26−28 weeks was positively associated with GDM risk with an adjusted odds ratio (aOR for smoking, education, parity, ethnicity, gestational weight gain, and (family) history of diabetes or GDM) of 2.12 (95% CI 1.07; 4.23), comparing the highest with the lowest tertile. Higher fT3 levels and a higher fT3-to-fT4 ratio were associated with a less favorable metabolic profile with higher BMI and more insulin resistance during pregnancy and postpartum. Women in the upper fT3 tertile and the upper fT3-to-fT4 ratio had a higher rate of preeclampsia [4.6% (10) vs. 1.0% (2), p = 0.040, and 4.4% (9) vs. 0.5% (1), p = 0.020], gestational hypertension [8.3% (18) vs. 3.1% (6), p = 0.034 and 8.9% (18) vs. 2.0% (4), p = 0.003], and caesarean sections [29.4% (63) vs. 16.1% (31), p = 0.002 and 32.2% (65) vs. 12.7% (25), p < 0.001]. Conclusion: A higher fT3-to-fT4 ratio late into pregnancy was associated with GDM, adverse pregnancy outcomes, and an adverse metabolic profile in early postpartum.

Estimating the risk of gestational diabetes mellitus based on the 2013 WHO criteria: a prediction model based on clinical and biochemical variables in early pregnancy.

AIMS: We aimed to develop a prediction model based on clinical and biochemical variables for gestational diabetes mellitus (GDM) based on the 2013 World Health Organization (WHO) criteria. METHODS: A total of 1843 women from a Belgian multi-centric prospective cohort study underwent universal screening for GDM. Using multivariable logistic regression analysis, a model to predict GDM was developed based on variables from early pregnancy. The performance of the model was assessed by receiver-operating characteristic (AUC) analysis. To account for over-optimism, an eightfold cross-validation was performed. The accuracy was compared with two validated models (van Leeuwen and Teede). RESULTS: A history with a first degree relative with diabetes, a history of smoking before pregnancy, a history of GDM, Asian origin, age, height and BMI were independent predictors for GDM with an AUC of 0.72 [95% confidence interval (CI) 0.69-0.76)]; after cross-validation, the AUC was 0.68 (95% CI 0.64-0.72). Adding biochemical variables, a history of a first degree relative with diabetes, a history of GDM, non-Caucasian origin, age, height, weight, fasting plasma glucose, triglycerides and HbA1c were independent predictors for GDM, with an AUC of the model of 0.76 (95% CI 0.72-0.79); after cross-validation, the AUC was 0.72 (95% CI 0.66-0.78), compared to an AUC of 0.67 (95% CI 0.63-0.71) using the van Leeuwen model and an AUC of 0.66 (95% CI 0.62-0.70) using the Teede model. CONCLUSIONS: A model based on easy to use variables in early pregnancy has a moderate accuracy to predict GDM based on the 2013 WHO criteria.

The 2019 Flemish consensus on screening for overt diabetes in early pregnancy and screening for gestational diabetes mellitus.

Screening for gestational diabetes mellitus (GDM) is important to improve pregnancy outcomes and to prevent type 2 diabetes after pregnancy. The 'International Association of Diabetes and Pregnancy Study Groups' (IADPSG) recommends a universal one-step approach with the 75 g oral glucose tolerance test (OGTT) for screening of GDM. The IADPSG recommendation remains controversial due to the important increase in GDM prevalence and increased workload. After review of the latest evidence and based on data from the 'Belgian Diabetes in Pregnancy' study, members of the Diabetes Liga, the Flemish associations of general physicians (Domus Medica), obstetricians (VVOG), midwives (VVOB), diabetes nurse educators (BVVDV) and clinical chemists (RBSLM) have reached a new consensus on screening for GDM in Flanders. This new consensus recommends universal screening for overt diabetes when planning pregnancy or at the latest at first prenatal contact, preferably by measuring the fasting plasma glucose by using the same diagnostic criteria as in the non-pregnant state. In women with impaired fasting glycaemia, but also in normoglycemic obese women and women with a previous history of GDM, lifestyle counselling is advised with screening for GDM with a 75 g OGTT at 24 weeks. In all other women, we recommend a two-step screening strategy with a 50 g glucose challenge test (GCT) at 24 weeks followed by a 75 g OGTT when the glucose level 1 hour after the GCT ≥130 mg/dl. Diagnosis of GDM is made using the IADPSG criteria for GDM. Postpartum screening for subsequent glucose abnormalities should be advocated and organized for every woman with GDM.

Screening and Management of Gestational Diabetes Mellitus after Bariatric Surgery.

Gestational diabetes mellitus (GDM) is a frequent medical complication during pregnancy. This is partly due to the increasing prevalence of obesity in women of childbearing age. Since bariatric surgery is currently the most successful way to achieve maintained weight loss, increasing numbers of obese women of childbearing age receive bariatric surgery. Bariatric surgery performed before pregnancy significantly reduces the risk to develop GDM but the risk is generally still higher compared to normal weight pregnant women. Women after bariatric surgery therefore still require screening for GDM. However, screening for GDM is challenging in pregnant women after bariatric surgery. The standard screening tests such as an oral glucose tolerance test are often not well tolerated and wide variations in glucose excursions make the diagnosis difficult. Capillary blood glucose measurements may currently be the most acceptable alternative for screening in pregnancy after bariatric surgery. In addition, pregnant women after bariatric surgery have an increased risk for small neonates and need careful nutritional and foetal monitoring. In this review, we address the risk to develop GDM after bariatric surgery, the challenges to screen for GDM and the management of women with GDM after bariatric surgery.