Clinical importance of the 75-g glucose tolerance test (GTT) in the prediction of large for gestational age (LGA) fetuses in non-diabetic pregnancies

The effect of 50 GR oral glucose tolerance test on fetal celiac artery and superior mesenteric artery Doppler parameters in healthy pregnancies

OBJECTIVES

To understand the effect of 50-g oral glucose tolerance test (OGTT) on fetal celiac artery and superior mesenteric artery (SMA) Doppler parameters.

METHODS

A total of 43 healthy pregnant women followed in our hospital were included in the study. All Doppler parameters of the celiac artery and SMA (peak systolic velocity (PSV); pulsatility index (PI); resistance index (RI); systolic/diastolic ratio (SD); time average maximum velocity (TAMAX)) were obtained by ultrasonography before and 1 h after OGTT.

RESULTS

The mean PSV value of the celiac artery decreased statistically significantly after OGTT (37.29 ± 11.96 cm/s; 29.51 ± 10.07 cm/s; p=0.002). While the mean of the PI was 2.09 ± 0.57 before the test, it was found to be 1.84 ± 0.64 after the test (p=0.027). Mean PSV (39.82 ± 13.07 cm/s; 35.19 ± 15.27 cm/s; p=0.104) and PI (2.21 ± 0.65; 2.11 ± 0.80; p=0.375) values of SMA were also found to be decreased without statistically significancy.

CONCLUSIONS

The data obtained from our study reveals that the PSV and PI values of celiac artery and SMA slightly decrease after OGTT.

Use of the 50-g glucose challenge test to predict small-for-gestational-age neonates

BACKGROUND

To determine a cutoff value for the 50-g glucose challenge test (50-g GCT) for the prediction of small-for-gestational-age (SGA) neonates.

METHODS

This retrospective cohort study was conducted among pregnant women who were screened with the 50-g GCT at Hacettepe University Hospital between 1 January 2016 and 31 March 2019. Patients with 50-g GCT values <74 mg/dL (<10th percentile) served as the study group (n = 244), while patients with 50-g GCT values between 74 to 139 mg/dL served as the control group (n = 3104). Groups were compared in terms of demographic features, clinical characteristics, and obstetric outcomes. Logistic regression analysis was used to determine independent predictors of SGA. Receiver operating characteristic curves were used to assess the performance of 50-g GCT values in predicting SGA.

RESULTS

Lower birthweight, birthweight percentile, and 5th-minute Apgar values, together with higher rates of SGA, were observed in the study group (P < .001 for all). A 50-g GCT value below the 10th percentile (odds ratio: 3.29, 95% CI: 2.31-4.69, P < .001) was a significant independent factor for SGA. A cutoff value of 89.5 mg/dL (84.9% sensitivity, 85.6% specificity) was determined for SGA.

CONCLUSIONS

Low 50-g GCT values (<89.5 mg/dL) may be an early indicator for SGA.

Management of Gestational Diabetes Mellitus

Once a woman is diagnosed with gestational diabetes mellitus (GDM), two strategies are considered for management; life-style modifications and pharmacological therapy. The management of GDM aims to maintain a normoglycemic state and to prevent excessive weight gain in order to reduce maternal and fetal complications. Lifestyle modifications include nutritional therapy and exercise. Calorie restriction with a low glycemic index diet is recommended to avoid postprandial hyperglycemia and to reduce insulin resistance. Blood glucose levels, HbA1c levels, and ketonuria are monitored to analyze the efficacy of conservative management. Pharmacological treatment is initiated if conservative strategies fail to provide expected glucose levels during follow-ups.Insulin has been the first choice for the treatment of diabetes during pregnancy. Recently, metformin has been used more commonly in diabetic pregnant women in cases when insulin cannot be prescribed, after its safety has been proven. However, a high percentage of women, which may be up to 46% may require additional insulin to maintain expected blood glucose levels. The evidence on the long-term safety of other oral anti-diabetics has been lacking yet.Women with diet-controlled GDM can wait for spontaneous labor expectantly in case there are no obstetric indications for birth. However, in women with GDM under insulin therapy or with poor glycemic control, elective induction at term is recommended by authorities.The women who have GDM during pregnancy should be counseled about their increased risks of impaired glucose tolerance, type 2 diabetes mellitus, hypertensive disorders, cardiovascular diseases, and metabolic syndrome.