A Pragmatic, Randomized Clinical Trial of Gestational Diabetes Screening.

BACKGROUND: Gestational diabetes mellitus is common and is associated with an increased risk of adverse maternal and perinatal outcomes. Although experts recommend universal screening for gestational diabetes, consensus is lacking about which of two recommended screening approaches should be used. METHODS: We performed a pragmatic, randomized trial comparing one-step screening (i.e., a glucose-tolerance test in which the blood glucose level was obtained after the oral administration of a 75-g glucose load in the fasting state) with two-step screening (a glucose challenge test in which the blood glucose level was obtained after the oral administration of a 50-g glucose load in the nonfasting state, followed, if positive, by an oral glucose-tolerance test with a 100-g glucose load in the fasting state) in all pregnant women who received care in two health systems. Guidelines for the treatment of gestational diabetes were consistent with the two screening approaches. The primary outcomes were a diagnosis of gestational diabetes, large-for-gestational-age infants, a perinatal composite outcome (stillbirth, neonatal death, shoulder dystocia, bone fracture, or any arm or hand nerve palsy related to birth injury), gestational hypertension or preeclampsia, and primary cesarean section. RESULTS: A total of 23,792 women underwent randomization; women with more than one pregnancy during the trial could have been assigned to more than one type of screening. A total of 66% of the women in the one-step group and 92% of those in the two-step group adhered to the assigned screening. Gestational diabetes was diagnosed in 16.5% of the women assigned to the one-step approach and in 8.5% of those assigned to the two-step approach (unadjusted relative risk, 1.94; 97.5% confidence interval [CI], 1.79 to 2.11). In intention-to-treat analyses, the respective incidences of the other primary outcomes were as follows: large-for-gestational-age infants, 8.9% and 9.2% (relative risk, 0.95; 97.5% CI, 0.87 to 1.05); perinatal composite outcome, 3.1% and 3.0% (relative risk, 1.04; 97.5% CI, 0.88 to 1.23); gestational hypertension or preeclampsia, 13.6% and 13.5% (relative risk, 1.00; 97.5% CI, 0.93 to 1.08); and primary cesarean section, 24.0% and 24.6% (relative risk, 0.98; 97.5% CI, 0.93 to 1.02). The results were materially unchanged in intention-to-treat analyses with inverse probability weighting to account for differential adherence to the screening approaches. CONCLUSIONS: Despite more diagnoses of gestational diabetes with the one-step approach than with the two-step approach, there were no significant between-group differences in the risks of the primary outcomes relating to perinatal and maternal complications. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development; ScreenR2GDM ClinicalTrials.gov number, NCT02266758.).

Impact of earlier gestational diabetes screening for pregnant people with obesity on maternal and perinatal outcomes.

OBJECTIVES: Gestational diabetes (GDM) screening at 24-28 weeks' gestation reduces risk of adverse maternal and perinatal outcomes. While experts recommend first-trimester screening for high-risk patients, including those with obesity, data supporting this recommendation is limited. METHODS: We implemented a systematic population intervention to encourage first-trimester GDM screening by oral glucose tolerance testing in a cohort of pregnant people with obesity in two integrated health systems from 2009 to 2013, and compared outcomes to the same population pre-intervention (2006-2009). Up to five years of postpartum glucose testing results (through 2018) were assessed among GDM cases in the post-intervention group. Primary outcomes were large-for-gestational-age birthweight (LGA); macrosomia; a perinatal composite outcome; gestational hypertension/preeclampsia; cesarean delivery; and medication treatment of GDM. RESULTS: A total of 40,206 patients (9,156 with obesity) were screened for GDM; 2,672 (6.6%) were diagnosed with GDM. Overall, multivariate adjusted risk for LGA and cesarean delivery were lower following the intervention (LGA: aOR 0.89 [0.82, 0.96]; cesarean delivery: 0.89 [0.85, 0.93]). This difference was more pronounced in patients diagnosed with GDM (LGA: aOR 0.52 [0.39, 0.70]; cesarean delivery 0.78 [0.65, 0.94]); insulin/oral hypoglycemic treatment rates for GDM were also higher post-intervention than pre-intervention (22 vs. 29%; p<0.0001). There were no differences for the other primary outcomes. Only 20% of patients diagnosed with GDM early in pregnancy who had postpartum testing had results in the overt diabetes range, suggesting a spectrum of diabetes detected early in pregnancy. CONCLUSIONS: First trimester GDM screening for pregnant people with obesity may improve GDM-associated outcomes.

Timing of Gestational Diabetes Diagnosis by Maternal Obesity Status: Impact on Gestational Weight Gain in a Diverse Population.

Background: We hypothesized that earlier gestational diabetes mellitus (GDM) diagnosis and treatment of high-risk women would reduce gestational weight gain (GWG) in the first trimester and overall. Materials and Methods: We evaluated timing of GDM diagnosis among 5,391 pregnant women who delivered singleton births 2010-2013 in a large diverse health maintenance organization (HMO). All GDM screening was by the same oral glucose tolerance testing protocol; GDM treatment protocols were also consistent irrespective of timing of diagnosis. Women without risk factors were universally screened at 24-28 weeks gestation (Usual). Early screening was recommended in obese and other high-risk women at the first prenatal visit; those who screened negative Early were rescreened at 24-28 weeks (Early+Usual). Results: Average GWG for all women was 12.8 kg; 10.7% of women were diagnosed with GDM. Average GWG for all women diagnosed with GDM was 10.7 kg, adjusted for gestational age. Women with EarlyGDM averaged 2.4 kg less GWG than women diagnosed with UsualGDM (p < 0.0001). Among obese women, only women diagnosed with EarlyGDM averaged overall GWG within Institute of Medicine (IOM) weight guidelines (mean 8.1 kg) and were weight neutral in the first trimester (-0.2 kg). Overall, 43% of all pregnant women exceeded IOM GWG guidelines (gained more total weight than recommended); 60% of obese women exceeded guidelines. Obese women diagnosed with GDM were less likely to exceed IOM guidelines if diagnosed earlier in pregnancy (35% EarlyGDM vs. 59% UsualGDM exceeded guidelines, p < 0.0001). Conclusion: Our results suggest that EarlyGDM diagnosis (and thus treatment) in high-risk women is beneficial for optimizing GWG.