Screening for Gestational Diabetes: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

JAMA. 2021 Aug 10;326(6):539-562. doi: 10.1001/jama.2021.10404.


Importance: Gestational diabetes is associated with several poor health outcomes.

Objective: To update the 2012 review on screening for gestational diabetes to inform the US Preventive Services Task Force.

Data sources: MEDLINE, EMBASE, and CINAHL (2010 to May 2020),, reference lists; surveillance through June 2021.

Study selection: English-language intervention studies for screening and treatment; observational studies on screening; prospective studies on screening test accuracy.

Data extraction and synthesis: Dual review of titles/abstracts, full-text articles, and study quality. Single-reviewer data abstraction with verification. Random-effects meta-analysis or bivariate analysis (accuracy).

Main outcomes and measures: Pregnancy, fetal/neonatal, and long-term health outcomes; harms of screening; accuracy.

Results: A total of 76 studies were included (18 randomized clinical trials [RCTs] [n = 31 241], 2 nonrandomized intervention studies [n = 190], 56 observational studies [n = 261 678]). Direct evidence on benefits of screening vs no screening was limited to 4 observational studies with inconsistent findings and methodological limitations. Screening was not significantly associated with serious or long-term harm. In 5 RCTs (n = 25 772), 1-step (International Association of Diabetes and Pregnancy Study Group) vs 2-step (Carpenter and Coustan) screening was significantly associated with increased likelihood of gestational diabetes (11.5% vs 4.9%) but no improved health outcomes. At or after 24 weeks of gestation, oral glucose challenge tests with 140- and 135-mg/dL cutoffs had sensitivities of 82% and 93%, respectively, and specificities of 82% and 79%, respectively, against Carpenter and Coustan criteria, and a test with a 140-mg/dL cutoff had sensitivity of 85% and specificity of 81% against the National Diabetes Group Data criteria. Fasting plasma glucose tests with cutoffs of 85 and 90 mg/dL had sensitivities of 88% and 81% and specificities of 73% and 82%, respectively, against Carpenter and Coustan criteria. Based on 8 RCTs and 1 nonrandomized study (n = 3982), treatment was significantly associated with decreased risk of primary cesarean deliveries (relative risk [RR], 0.70 [95% CI, 0.54-0.91]; absolute risk difference [ARD], 5.3%), shoulder dystocia (RR, 0.42 [95% CI, 0.23-0.77]; ARD, 1.3%), macrosomia (RR, 0.53 [95% CI, 0.41-0.68]; ARD, 8.9%), large for gestational age (RR, 0.56 [95% CI, 0.47-0.66]; ARD, 8.4%), birth injuries (odds ratio, 0.33 [95% CI, 0.11-0.99]; ARD, 0.2%), and neonatal intensive care unit admissions (RR, 0.73 [95% CI, 0.53-0.99]; ARD, 2.0%). The association with reduction in preterm deliveries was not significant (RR, 0.75 [95% CI, 0.56-1.01]).

Conclusions and relevance: Direct evidence on screening vs no screening remains limited. One- vs 2-step screening was not significantly associated with improved health outcomes. At or after 24 weeks of gestation, treatment of gestational diabetes was significantly associated with improved health outcomes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Systematic Review

MeSH terms

  • Diabetes, Gestational / diagnosis*
  • Diabetes, Gestational / therapy
  • Female
  • Glucose Tolerance Test
  • Humans
  • Infant, Newborn
  • Mass Screening* / adverse effects
  • Mass Screening* / methods
  • Practice Guidelines as Topic
  • Pregnancy
  • Pregnancy Outcome
  • Pregnancy Trimester, Second
  • Risk Assessment