Gestational Diabetes Screening: Which ACOG Document Governs Your Protocol Now?
Gestational diabetes screening guidance sits in three ACOG documents carrying three different dates. Here is the map from the 2018 practice bulletins to the consolidated update that replaced parts of them.
Why Gestational Diabetes Screening Is in the News Right Now
Gestational diabetes screening at ACOG now sits in three documents with three different dates, and the dates do not say which one wins. The page for Practice Bulletin No. 190 shows a 2026 reaffirmation stamp beside a link to the July 2024 Clinical Practice Update that already replaced parts of it.
Two housekeeping changes make this worth resolving now. ACOG has closed the Practice Bulletin series, so bulletins stand until individually replaced or withdrawn. From August 2026 its clinical library moves to Obstetrics & Gynecology and a members-only app, so protocols linking to acog.org pages need checking.
The short version
- Gestational diabetes screening recommendations now come from the July 2024 Clinical Practice Update, not Practice Bulletin No. 190.
- Glucose targets, pharmacotherapy, fetal surveillance and delivery timing still come from Bulletins 190 and 201.
- Four screening recommendations moved; the two-step approach was not one of them.
- The 2026 reaffirmation of Bulletin 190 does not reverse the 2024 update.
The Background
Practice Bulletin No. 190, from February 2018, has been the working reference for gestational diabetes mellitus (GDM), hyperglycemia first recognized in pregnancy. Bulletin No. 201, from that December, covered pregestational diabetes. Screening advice was split between the two.
The July 2024 Clinical Practice Update states on its face that it updates both bulletins. Its scope is narrow by design: it consolidates the screening material and leaves the rest of each document standing.
That yields a clean mapping rule. Who to test, when, at which thresholds, and when to retest after delivery come from the 2024 update; how to treat still comes from the bulletins.
Four recommendations shifted in the move.
- Routine GDM screening before 24 weeks is no longer recommended, because early diagnosis and treatment have not consistently improved outcomes.
- Early testing in at-risk patients survives, but as screening for pregestational diabetes at entry to prenatal care.
- Carpenter and Coustan thresholds are preferred over the higher National Diabetes Data Group (NDDG) values on the 100-g three-hour oral glucose tolerance test (OGTT).
- Postpartum testing may be done during the delivery admission rather than only at 4 to 12 weeks.
The architecture did not change. A non-fasting 50-g challenge at 24 to 28 weeks followed by the three-hour OGTT remains the default, with the one-step 75-g OGTT available on clinical judgment.
The Evidence So Far
Northwestern University investigators, writing in JAMA Internal Medicine in December 2025, analyzed nearly 13 million first singleton births and found GDM rose from 58 to 79 cases per 1,000 between 2016 and 2024. Among the main racial and ethnic groups, the 2024 rate ran from 70.7 per 1,000 in White patients to 137 in American Indian and Alaska Native patients.
Gestational diabetes has been persistently increasing for more than 10 years Nilay S. Shah, MD, Northwestern University Feinberg School of Medicine, senior author, in a statement issued with the analysis
The case against routine early screening rests on TOBOGM (Treatment of Booking Gestational Diabetes Mellitus), the only large randomized trial of treating GDM found before 20 weeks. An adverse neonatal outcome occurred in 24.9 percent of the immediate-treatment group and 30.5 percent of controls, an adjusted difference of 5.6 percentage points (95% confidence interval, or CI, 1.2 to 10.1) and a number needed to treat (NNT) of 18.
The US Preventive Services Task Force stopped short of ACOG’s position in 2021: a B recommendation for screening at or after 24 weeks, and an I statement for earlier screening, meaning insufficient evidence rather than advice against it.
The Practical Question for Gestational Diabetes Screening Protocols
For most practices this is a documentation problem before a clinical one. Three edits cover the bulk of it.
- Relabel the early test. When a patient with risk factors is tested at entry to care, the order and note should say screening for pregestational diabetes, not early gestational diabetes screening. A hemoglobin A1c of 6.5 percent or higher meets criteria for overt diabetes.
- Check what the laboratory reports. Carpenter and Coustan thresholds for the three-hour OGTT are 95, 180, 155 and 140 mg/dL; NDDG values are 105, 190, 165 and 145 mg/dL. A standing order still set to NDDG will miss patients ACOG now expects to treat.
- Add the inpatient postpartum pathway. A 75-g two-hour OGTT during the delivery admission is an accepted alternative for patients unlikely to return, though 4 to 12 weeks remains the reference timing.
Where Experts Disagree on Gestational Diabetes Screening
The unsettled question is how to read TOBOGM. ACOG holds that a modest composite effect does not justify testing every patient early. The trial’s investigators point to the subgroups, where participants with higher early glucose values and those treated before 14 weeks showed larger absolute reductions.
Thresholds are the second fault line. The International Association of Diabetes and Pregnancy Study Groups favors a one-step 75-g OGTT that labels considerably more patients, while ACOG’s two-step approach remains the US default. The Task Force found both strategies detect the condition accurately, with no outcome advantage for either.
What to Watch For
- Whether ACOG folds gestational diabetes screening into one clinical practice guideline replacing Bulletins 190 and 201.
- Whether the Task Force revisits its I statement for screening before 24 weeks now that TOBOGM has reported.
- Whether the August 2026 migration breaks guideline links in protocols and order sets.
Until a consolidated guideline arrives, check what a cited ACOG document is being cited for. A 2018 bulletin carrying a 2026 reaffirmation stamp is still the right source for treatment, and the wrong one for gestational diabetes screening.
Sources
- American College of Obstetricians and Gynecologists. ACOG Clinical Practice Update: Screening for Gestational and Pregestational Diabetes in Pregnancy and Postpartum. Obstet Gynecol 2024;144:e20–e23. ACOG Clinical Practice Update on diabetes screening in pregnancy
- American College of Obstetricians and Gynecologists. Practice Bulletin No. 190: Gestational Diabetes Mellitus. Obstet Gynecol 2018;131:e49–e64. ACOG Practice Bulletin No. 190, reaffirmed 2026
- American College of Obstetricians and Gynecologists. Practice Bulletin No. 201: Pregestational Diabetes Mellitus. Obstet Gynecol 2018;132:e228–e248. ACOG Practice Bulletin No. 201 on pregestational diabetes
- US Preventive Services Task Force. Screening for Gestational Diabetes: US Preventive Services Task Force Recommendation Statement. JAMA 2021;326:531–538. USPSTF recommendation statement on gestational diabetes screening
- Simmons D, Immanuel J, Hague WM, et al. Treatment of Gestational Diabetes Mellitus Diagnosed Early in Pregnancy. N Engl J Med 2023;388:2132–2144. TOBOGM randomized trial of early gestational diabetes treatment
- Lam EL, Walker JM, Wang MC, Venkatesh KK, Khan SS, Shah NS. Gestational Diabetes in the US From 2016 to 2024. JAMA Intern Med 2026;186:269–271. JAMA Internal Medicine analysis of US gestational diabetes rates
- American College of Obstetricians and Gynecologists. ACOG Clinical: clinical guidance document series. ACOG overview of its clinical guidance document types
- American College of Obstetricians and Gynecologists. ACOG Clinical Subscription: changes to clinical guidance access. ACOG notice on August 2026 clinical guidance access changes