Analysis of glucose tolerance in twin gestations using an oral glucose load

Characteristics of the oral glucose tolerance test in women with different pre-pregnancy body mass index and the effect of gestational diabetes mellitus on twin pregnancy outcomes

OBJECTIVE

This study aimed to investigate the mid-pregnancy blood glucose levels of women with singleton or twin pregnancies.

METHOD

The relationship between blood glucose levels and Gestational Diabetes Mellitus (GDM) was studied in women with different pre-pregnancy Body Mass Index (BMI), and the effect of GDM on twin pregnancy outcomes was analyzed. Women with twin (n = 1,985) and singleton (n = 1,985) pregnancies were categorized into underweight (BMI < 18.5 kg/m2, n = 597), normal weight (BMI: 18.5-23.9 kg/m2, n = 2,575), and overweight/obese (BMI ≥ 24 kg/m2, n = 798) groups.

RESULTS

The incidence of GDM was 21.01% in women with twin pregnancies. Among the women with GDM in twin pregnancies, 38.37% had at least two abnormal blood glucose levels. The incidence of these parameters increased with preconception BMI, and the incidence of twin pregnancies was higher than that of singleton pregnancies (p < 0.001). In the normal weight and overweight/obese group, the oral glucose tolerance test glucose level and incidence of GDM were higher in women with twin than singleton pregnancies (p < 0.05). For twin pregnancies, the prevalence of selective fetal growth restriction was higher and anemia was lower in the GDM group than in the non-GDM group (all p < 0.05).

CONCLUSION

Therefore, a greater emphasis should be placed on BMI before conception, and well-controlled GDM does not increase adverse pregnancy outcomes for twin pregnancies.

Glucose tolerance in singleton, twin and triplet pregnancies

BACKGROUND

Data regarding the effects of multifetal pregnancy on the incidence of gestational diabetes mellitus (GDM) are inconsistent and even conflicting. Twin pregnancies have been associated with no increase, a marginal increase or a higher incidence of gestational diabetes. In triplet pregnancies, these effects have not been investigated yet.

OBJECTIVES

To analyze the results of the glucose challenge and tolerance tests in singleton, twin and triplet pregnancies.

STUDY DESIGN

A retrospective database analysis of pregnant women with singletons, twins or triplets who had complete results of the 50 g glucose challenge test (GCT) and the 100 g oral glucose tolerance test (OGTT). The cohort included 12,382 singletons, 515 twins and 39 triplets.

RESULTS

There were significantly higher rates of abnormal GCTs in twins and triplets compared to singletons (45.4% and 33.3%, respectively vs. 13.7%, P<0.001 and P<0.05). Significantly higher rates of gestational diabetes in twins (10.1% vs. 2.9 %, P<0.001) and triplets (12.8% vs. 2.9%, P<0.05) compared to singletons were observed. Mean glucose levels after the GCT were higher in twins compared to singletons, and even more in triplets (108 mg/dL in singletons vs. 120 mg/dL in twins vs. 129 mg/dL in triplets, P<0.001).

CONCLUSIONS

Glucose intolerance is aggravated in multifetal pregnancies. The likelihood of an abnormal GCT and gestational diabetes is higher in twins and triplets compared to singletons.

Outcome of twin pregnancies associated with glucose intolerance

OBJECTIVES

There is little information about the impact of hyperglycaemia in twin pregnancies. The objective of our study was to evaluate the maternal, foetal and neonatal complications in patients with twin pregnancy and glucose intolerance defined by gestational diabetes mellitus and gestational mild hyperglycaemia.

STUDY DESIGN

We performed a single-centre retrospective study. Screening for gestational diabetes was achieved by a two-step method. Patients were managed according to the French guidelines. After matching for age and body mass index, outcomes were compared in 177 patients with glucose intolerance and 509 controls. Macrosomia was defined as birth weight above the 90th percentile of gestational age adjusted for parity, foetal sex and maternal biometrics.

RESULTS

Prevalence of glucose intolerance was 17.5% in our population. Complications of pregnancy and mode of delivery were similar between the two groups. Caesarean section was associated with age >35 years, vascular complications of pregnancy and non-cephalic presentation of the first twin. Rate of macrosomia was not different between the two groups. The only risk factor for macrosomia was a history of macrosomia in a previous pregnancy (odds ratio = 5.9, 95% confidence interval = 1.8-19.2).

CONCLUSION

Twin pregnancies complicated by glucose intolerance were not associated with an increased risk of macrosomia or Caesarean section. Further studies should assess the value of screening gestational diabetes mellitus in twin pregnancies.

Definition, epidemiology, risk factors

Gestational diabetes mellitus is defined as glucose intolerance that begins or is first recognized during pregnancy. Its prevalence, generally situated between 2-6%, may reach 10-20% in high-risk populations, with an increasing trend across most racial/ethnic groups studied. Among traditional risk factors, previous gestational diabetes, advanced maternal age and obesity have the highest impact on gestational diabetes risk. Racial/ethnic origin and family history of type 2 diabetes have a significant but moderate impact (except for type 2 diabetes in siblings). Several non traditional factors have been recently characterized, either physiological (low birthweight and short maternal height) or pathological (polycystic ovaries). The multiplicity of risk factors and their interactions results in a low reliability of risk prediction on an individual basis.