The relationship between fasting plasma glucose in the first trimester of pregnancy and the incidence of gestational diabetes in Iran

First-trimester fasting plasma glucose as a predictor of subsequent gestational diabetes mellitus and adverse fetomaternal outcomes: A systematic review and meta-analysis

BACKGROUND

The implication of intermediately elevated fasting plasma glucose (FPG) in the first trimester of pregnancy is uncertain.

PURPOSE

The primary outcome of the meta-analysis was to analyze if intermediately elevated first-trimester FPG could predict development of GDM at 24-28 weeks. The secondary outcomes were to determine if the commonly used FPG cut-offs 5.1 mmol/L (92 mg/dL), 5.6 mmol/L (100 mg/dL), and 6.1 mmol/L (110 mg/dL) correlated with adverse pregnancy events.

DATA SOURCES

Databases were searched for articles published from 2010 onwards for studies examining the relationship between first-trimester FPG and adverse fetomaternal outcomes.

STUDY SELECTION

A total of sixteen studies involving 115,899 pregnancies satisfied the inclusion criteria.

DATA EXTRACTION AND DATA SYNTHESIS

Women who developed GDM had a significantly higher first-trimester FPG than those who did not [MD 0.29 mmoL/l (5 mg/dL); 95 % CI: 0.21-0.38; P < 0.00001]. First-trimester FPG ≥5.1 mmol/L (92 mg/dL) predicted the development of GDM at 24-28 weeks [RR 3.93 (95 % CI: 2.67-5.77); P < 0.0000], pre-eclampsia [RR 1.55 (95%CI:1.14-2.12); P = 0.006], gestational hypertension [RR1.47 (95%CI:1.20-1.79); P = 0.0001], large-for-gestational-age (LGA) [RR 1.32 (95%CI:1.13-1.54); P = 0.0004], and macrosomia [RR1.29 (95%CI:1.15-1.44); P < 0.001]. However, at the above threshold, the rates of preterm delivery, lower-segment cesarean section (LSCS), small-for gestational age (SGA), and neonatal hypoglycemia were not significantly higher. First-trimester FPG ≥5.6 mmol/L (100 mg/dL) correlated with occurrence of macrosomia [RR1.47 (95 % CI:1.22-1.79); P < 0.0001], LGA [RR 1.43 (95%CI:1.24-1.65); P < 0.00001], and preterm delivery [RR1.51 (95%CI:1.15-1.98); P = 0.003], but not SGA and LSCS.

LIMITATIONS

Only one study reported outcomes at first-trimester FPG of 6.1 mmol/L (110 mg/dL), and hence was not analyzed.

CONCLUSION

The risk of development of GDM at 24-28 weeks increased linearly with higher first-trimester FPG. First trimester FPG cut-offs of 5.1 mmol/L (92 mg/dL) and 5.6 mmol/L (100 mg/dL) predicted several adverse pregnancy outcomes.

Hemoglobin at the first visit of pregnancy and developing gestational diabetes mellitus: Results of a prospective registry cohort study

BACKGROUND AND AIM

Gestational diabetes mellitus (GDM) is associated with a considerable risk of diabetes in the future. Few studies focused on the association between hemoglobin levels and developing gestational diabetes. This study aimed to determine the association of hemoglobin in early pregnancy and developing gestational diabetes mellitus.

METHODS

A prospective registry cohort study was designed for the recall of women with gestational diabetes mellitus. The registry was implemented in the health centers of Ahvaz City in 2019. Biological and clinical assessments were done, and interviewer-administered questionnaires were used to collect data on socio-demographic Features, medical and obstetric history, and risk factors of GDM. SPSS used for data analysis. The optimal hemoglobin cut-off point, its sensitivity, and specificity for the prediction of GDM were estimated using ROC analysis.

RESULTS

The prevalence of anemia was 17.1% in pregnant women (8.1% in women with gestational diabetes versus %24.2% in the healthy group, p < 0.001). The hemoglobin mean in women with GDM was significantly higher than in healthy women (P < 0.001). Hemoglobin at the first visit was significantly associated with a greater risk of gestational diabetes (OR = 3.80, 95% CI: 3.05-4.74). The area under the curve (AUC) was 0.76 (95% CI 0.73-79), and the optimal cut-off point for hemoglobin was 11.90 g/dL, with a sensitivity of 75% and a specificity of 68%. Women with a higher hemoglobin level had a 3.8- more risk of developing GDM.

CONCLUSION

Measurement of hemoglobin can be a relatively good tool for predicting gestational diabetes in the first months of pregnancy. The combination of hemoglobin with fasting blood sugar and BMI improves the predictive value for gestational diabetes incidence.

Early Gestational Diabetes Mellitus: Diagnostic Strategies and Clinical Implications

Preexisting diabetes mellitus (DM) should be ruled out early in pregnancy in those at risk. During screening, a significant proportion of women do not reach the threshold for overt DM but fulfill the criteria used for diagnosing conventional gestational DM (cGDM). There is no consensus on the management of pregnancies with intermediate levels of hyperglycemia thus diagnosed. We have used the term early gestational DM (eGDM) for this condition and reviewed the currently available literature. Fasting plasma glucose (FPG), oral glucose tolerance test, and glycated hemoglobin (HbA1c) are the commonly employed screening tools in early pregnancy. Observational studies suggest that early pregnancy FPG and Hba1c correlate with the risk of cGDM and adverse perinatal outcomes. However, specific cut-offs, including those proposed by the International Association of the Diabetes and Pregnancy Study Group, do not reliably predict the development of cGDM. Emerging data, though indicate that FPG ≥ 92 mg/dL (5.1 mmol/L), even in the absence of cGDM, signals the risk for perinatal complication. Elevated HbA1c, especially a level ≥ 5.9%, also correlates with the risk of cGDM and worsened outcome. HbA1c as a diagnostic test is however besieged with the usual caveats that occur in pregnancy. The studies that explored the effects of intervention present conflicting results, including a possibility of fetal malnutrition and small-for-date baby in the early treatment group. Diagnostic thresholds and glycemic targets in eGDM may differ, and large multicenter randomized controlled trials are necessary to define the appropriate strategy.