Use of the 50-g glucose challenge test to predict excess delivery weight

Does Iodine Intake Modify the Effect of Maternal Dysglycemia on Birth Weight in Mild-to-Moderate Iodine-Deficient Populations? A Mother-Newborn Prospective Cohort Study

It is unclear how maternal glycemic status and maternal iodine status influence birth weight among individuals with mild-to-moderate iodine deficiency (ID). We studied the association between birth weight and both maternal glucose levels and iodine intake among pregnant women with mild-to-moderate ID. Glucose values were assessed using a glucose challenge test (GCT) and non-fasting glucose levels that were determined before delivery; individuals' iodine statuses were assessed using an iodine food frequency questionnaire; and serum thyroglobulin (Tg) and urinary iodine concentrations (UIC) were used to assess each group's iodine status. Thyroid antibodies and free thyroxine (FT4) levels were measured. Obstetric and anthropometric data were also collected. Large-for-gestational age (LGA) status was predicted using a Cox proportional hazards model with multiple confounders. Tg > 13 g/L was independently associated with LGA (adjusted hazard ratio = 3.4, 95% CI: 1.4-10.2, p = 0.001). Estimated iodine intake correlated with FT4 among participants who reported consuming iodine-containing supplements (ICS) after adjusting for confounders (β = 0.4, 95% CI: 0.0002-0.0008, p = 0.001). Newborn weight percentiles were inversely correlated with maternal FT4 values (β = -0.2 95% CI:-0.08--56.49, p = 0.049). We conclude that in mild-to-moderate ID regions, insufficient maternal iodine status may increase LGA risk. Iodine status and ICS intake may modify the effect that maternal dysglycemia has on offspring weight.

Mediation effect of maternal triglyceride and fasting glucose level on the relationship between maternal overweight/ obesity and fetal growth: a prospective cohort study

BACKGROUND

Previous studies have suggested that maternal overweight/obesity is asscociated with macrosomia. The present study aimed to investigate the mediation effects of fasting plasma glucose (FPG) and maternal triglyceride (mTG) in the relationship between maternal overweight/obesity and large for gestational age (LGA) among non-diabetes pregnant women.

METHODS

This prospective cohort study was conducted in Shenzhen from 2017 to 2021. A total of 19,104 singleton term non-diabetic pregnancies were enrolled form a birth cohort study. FPG and mTG were measured at 24-28 weeks. We analyzed the association of maternal prepregancy overweight/obesity with LGA and mediation effects of FPG and mTG. Multivariable logistic regression analysis and serial multiple mediation analysis were performed. The odds ratio (OR) and 95% confidence intervals (CIs) were calculated.

RESULTS

Mothers who were overweight or obese had higher odds of giving birth to LGA after adjusting potential confounders (OR:1.88, 95%CI: 1.60-2.21; OR:2.72, 95%CI: 1.93-3.84, respectively). The serial multiple mediation analysis found prepregnancy overweight can not only have a direct positive effect on LGA (effect = 0.043, 95% CI: 0.028-0.058), but also have an indirect effect on the LGA through two paths: the independent mediating role of FPG (effect = 0.004, 95% CI: 0.002-0.005); the independent mediating role of mTG (effect = 0.003,95% CI: 0.002-0.005). The chain mediating role of FPG and mTG has no indirect effect. The estimated proportions mediated by FPG and mTG were 7.8% and 5.9%. Besides, the prepregnancy obesity also has a direct effect on LGA (effect = 0.076; 95%CI: 0.037-0.118) and an indirect effect on LGA through three paths: the independent mediating role of FPG (effect = 0.006; 95%CI: 0.004-0.009); the independent mediating role of mTG (effect = 0.006; 95%CI: 0.003-0.008), and the chain mediating role of FPG and mTG (effect = 0.001; 95%CI: 0.000-0.001). The estimated proportions were 6.7%, 6.7%, and 1.1%, respectively.

CONCLUSION

This study found that in nondiabetic women, maternal overweight/obesity was associated with the occurence of LGA, and this positive association was partly mediated by FPG and mTG, suggesting that FPG and mTG in overweight/obese nondiabetic mothers deserve the attention of clinicians.

Maternal Preconception Glucose Homeostasis and Insulin Resistance Are Associated with Singleton and Twin Birthweight of Neonates Conceived by PCOS Women Undergoing IVF/ICSI Cycles

Polycystic ovary syndrome (PCOS) can induce fertility and metabolism disorders, which may increase the prevalence of glucose metabolism disorders and cause health hazards to women and their offspring. We aim to evaluate the effect of maternal preconception glucose metabolism on neonatal birthweight in PCOS women undergoing IVF/ICSI cycles. We retrospectively analyzed 269 PCOS women who delivered 190 singletons and 79 twins via IVF/ICSI at a reproductive center. The effects of maternal preconception glucose metabolism indicators on singleton and twin birthweight were evaluated using generalized linear models and generalized estimate equations, respectively. The potential nonlinear associations were evaluated using generalized additive models. The analyses were further stratified by maternal preconception BMI and delivery mode to evaluate the possible interaction effects. Among PCOS women, maternal preconception fasting plasma glucose (FPG) and glycohemoglobin (HbA1c) had significant negative associations with singleton birthweight (all p for trends = 0.04). We also found an overweight-specific association between elevated maternal preconception 2 h plasma insulin (2hPI) and twin birthweight (p for interactions = 0.05) and a caesarean-specific association between maternal preconception HbA1c and singleton birthweight (p for interactions = 0.02) in PCOS women. Maternal preconception glucose metabolism may affect neonatal birthweight, suggesting the importance of preconception glucose and insulin management for PCOS women. Further large prospective cohorts and animal studies are needed to confirm these findings and investigate the potential mechanisms.

Predictive Value of First-Trimester Glycosylated Hemoglobin Levels in Gestational Diabetes Mellitus: A Chinese Population Cohort Study

This study was aimed at exploring the predictive value of first-trimester glycosylated hemoglobin (HbA1c) levels in the diagnosis of gestational diabetes mellitus (GDM). A total of 744 pregnant women registered at the Peking University International Hospital between March 2017 and March 2019 were included in this study. Data on personal characteristics and biochemical indicators of the pregnant women were collected during the first trimester. The International Association of Diabetes and Pregnancy Study Groups has adopted specific diagnostic criteria as the gold standard for the diagnosis of GDM. Receiver operating characteristic (ROC) curve statistics were used to assess the predictive value of first-trimester HbA1c levels in the diagnosis of GDM. HbA1c levels in the first trimester were significantly higher in the GDM group than in the non-GDM group (5.23% ± 0.29% vs. 5.06 ± 0.28%, P < 0.05). The first-trimester HbA1c level was an independent risk factor for gestational diabetes. The area under the ROC curve (AUC) of HbA1c for GDM was 0.655 (95% confidence interval 0.620-0.689, P < 0.001). The positive likelihood ratio was the highest at HbA1c = 5.9%, sensitivity was 2.78, and specificity was 99.83%. There was no statistical difference in AUC between fasting blood glucose and HbA1c (P = 0.407). First-trimester HbA1c levels can be used to predict GDM. The risk of GDM was significantly increased in pregnant women with first-trimester HbA1c levels > 5.9%. There was no statistical difference between first-trimester HbA1c and fasting blood glucose levels in predicting GDM.

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.

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

Objective To demonstrate clinical importance of the 75-g glucose tolerance test (GTT) in the prediction of large for gestational age (LGA) fetuses in non-diabetic pregnancies. Methods We retrospectively evaluated 75-g GTT screening results of 356 pregnancies without prompt diagnosis of gestational diabetes mellitus (GDM) between January 2013 and December 2017. Newborns with a birthweight greater than the 90th percentile were evaluated as LGA. Pregnancies with LGA and non-LGA fetuses were compared by demographic and historical factors - maternal age, gravidity, parity, birthweight, birthweek, GTT results and birthweight percentiles - via Student's t-test. Multiple linear regression using the backward elimination method was performed to define the correlation between parameters and LGA (P-value of <0.20 was identified as the threshold). Receiver operator characteristics (ROC) curve analysis was performed for further analysis. Results The cohort was consisted of 45 (12.6%) and 311 (87.4%) pregnancies with LGA and non-LGA fetuses, respectively. Maternal age and 2nd-h GTT results were found to be significantly higher in patients with LGA newborns (P<0.001 and P=0.016, respectively). Fasting glucose levels and GTT 1st-h results were also higher (P=0.112, P=0.065). The coefficient of multiple determination (R2) was 0.055 by multiple linear regression analysis. Accordingly, GTT 2nd-h result and maternal age were statistically significant and contributed to the explanation of LGA, although the R2 value was not that much higher (P=0.016; P=0.001). Maternal age and GTT 2nd-h results were found to be associated with LGA fetuses with area under the curve (AUC) values of 0.662 and 0.608 according to ROC curve analysis. Conclusion Maternal age and 75-g GTT 2nd-h results were significantly higher in gestations with LGA newborns without GDM.