One elevated oral glucose tolerance test value in pregnancy increases the risk for future diabetes mellitus type 2

Risk for fetal malformations and unfavorable neonatal outcomes in early-onset gestational diabetes mellitus

BACKGROUND

Early-onset gestational diabetes mellitus (GDM) is diagnosed before the 24th gestational week. Since early GDM is associated with first trimester hyperglycemia, many clinicians treat these women as having pre-GDM. However, whether early GDM increases the risk for unfavorable pregnancy outcomes and particularly for fetal malformations to a greater extent than late-onset GDM were not studied sufficiently. We aimed to examine the effect of early-onset GDM on unfavorable pregnancy outcomes.

METHODS

A retrospective cohort study of women with GDM delivering singletons during 2005-2018 was conducted. Women were divided into GDM diagnosed at the first (Trimester1; up to 13.6 weeks; N = 117), the second (Trimester2; up to 23.6 weeks; N = 126), and the third trimester (Trimester3; N = 2334). The primary outcomes were neonatal malformations and a composite of large-for-age newborns, hypoglycemia and hyperbilirubinemia treated with phototherapy. Comparisons were made between early- (Trimester1 + Trimester2-groups) and late-onset GDM (Trimester3-group), and between the three trimesters.

RESULTS

Fetal malformations were low and comparable between the trimester1, trimester2, trimester3 groups (2 (1.7%), 3 (2.4%), and 110 (4.7%), respectively). The composite neonatal complications was similar between the groups (68 (58%), 58 (46%), and 1087 (47%), respectively). In early-onset, the rates of neonatal hypoglycemia and shoulder dystocia were higher than in the late-onset GDM group (OR 95% CI 3.5 [2.0-6.1] and 10.3 [2.4-44.6], respectively). Macrosomia was higher in trimester1 compared with trimester2 and trimester3 cohorts (OR 95% CI 5.3 [1.7-16.9] and 2.8 [1.5-5.2], respectively).

CONCLUSIONS

The risk for fetal malformations was low and comparable between the first, second and third trimester GDM. Since the risks for macrosomia, shoulder dystocia, and neonatal hypoglycemia are higher in early-onset GDM, these women should undergo strict glycemic control, intensive monitoring, and careful neonatal evaluation.

Maternal and fetal outcomes of pregnancies associated with single versus double abnormal values in 100 gr glucose tolerance test

Purpose of the study

Comparing maternal and fetal outcomes in pregnancies associated with single versus double abnormal values in 100 gr oral glucose tolerance test (OGTT).

Methods

This cohort study was performed in Arash women's Hospital, Tehran, Iran from 2019 to 2020. Patients with normal fasting blood sugar (FBS) tests were divided into two groups according to their OGTT results. The first group had a single abnormal value in their OGTT and the second group showed two abnormal values. Both groups were followed regularly until the end of pregnancy.

Results

Our results showed higher rates of macrosomia (birth of newborns weighed over 4 kg) and the need for pharmacological treatment for the management of GDM in the second group (P = 0.05). There were no differences between the two groups in terms of other maternal (polyhydramnios, shoulder dystocia, operative vaginal delivery, atony, postpartum bleeding, cesarean delivery, preeclampsia, and IUFD) and fetal outcomes (Apgar score, seizure, NICU admission, and hypoglycemia in the first 24 h).

Conclusion

We found no significant differences between pregnant women with single and double abnormal values in 100 gr OGTT regarding maternal and neonatal outcomes, except for macrosomia and need for pharmaceutical treatment.

Clinical implications of the 100-g oral glucose tolerance test in the third trimester

PURPOSE

The clinical implications of gestational diabetes mellitus (GDM) diagnosed in the third trimester are not well established and controversy continues regarding the performance of diagnostic tests beyond 28-week gestation. This study aimed to evaluate the incidence of abnormal third trimester oral glucose tolerance test (OGTT) results in women at high risk and to compare the obstetric and neonatal outcomes with those of women with normal OGTT results.

METHODS

The study included 372 women who completed late (>29 weeks) 100-g OGTT due to suspected fetal macrosomia, polyhydramnios or a personal risk factor for GDM, diagnosed according to the Carpenter & Coustan criteria. Women with only one abnormal OGTT value were diagnosed with GDM by abnormal glucose follow-up and analyzed separately. Obstetric and neonatal outcomes were compared between the GDM and the non-GDM groups.

RESULTS

GDM was diagnosed in 85/372 (22%) women, including 35 (59.3%) women with one abnormal OGTT value who were later diagnosed with GDM. Of 200 women who had a normal 1-h 50-g glucose challenge test at 24-28 weeks, late GDM was diagnosed in 33 (16.5%). Seventy-six (89.5%) of those with GDM were treated by dietary therapy and 9 (10.5%) by pharmacological therapy. Among women with GDM, large-for-gestational-age fetuses, labor induction and elective cesarean section were more prevalent than for those without GDM. Significant differences were not found between the groups in macrosomia and neonatal outcomes.

CONCLUSIONS

The performance of OGTT in women with risk factors during the third trimester should be considered following further prospective trials.