Based on its review of the evidence, the task force has recommended screening for gestational diabetes in asymptomatic pregnant patients at 24 weeks of gestation or later. This is a “B” recommendation.
The task force found insufficient evidence to recommend for or against screening for gestational diabetes in pregnant patients before 24 weeks of gestation — an “I” statement.
“Gestational diabetes can cause serious health problems for pregnant people and their babies,” said Chien-Wen Tseng, M.D., M.P.H., a family physician and task force member, in a news release. “Fortunately, screening for gestational diabetes at or after 24 weeks is simple, safe and effective, and can help to keep pregnant people and their babies healthy.”
The draft recommendation applies to pregnant people who have not been previously diagnosed with type 1 or type 2 diabetes and who do not have signs or symptoms of gestational diabetes.
The CDC estimates that gestational diabetes affects between 2% and 10% of all pregnancies in the United States each year. Having gestational diabetes can increase the risk of high blood pressure during pregnancy, as well as the risks of preterm birth and large infant birth weight. While blood sugar levels usually return to normal after giving birth, about half of all people who experience gestational diabetes go on to develop type 2 diabetes.
With only slight variations in wording, the draft recommendation concurs with the task force’s 2014 recommendation statement on the topic. The 2014 recommendation also gave a B recommendation to screening for gestational diabetes in asymptomatic pregnant patients after 24 weeks of gestation and an I statement for such screening earlier.
The AAFP supported the 2014 recommendation.
To update the previous recommendation, the task force commissioned a systematic review to evaluate the accuracy, benefits and harms of screening for gestational diabetes, as well as the benefits and harms of treatment for the mother and infant. Data sources included articles published between 2010 and May 2020, with additional surveillance conducted through December 2020. A total of 18 trials and 87 observational studies were included in the review.
The review found no randomized, controlled trials that addressed the direct benefits or harms of screening for gestational diabetes. Results from four observational studies that compared screening to no screening were mixed.
Overall, the task force found that diagnosis of gestational diabetes using more inclusive criteria was likely to identify additional patients who are at increased risk of adverse maternal and fetal/neonatal outcomes. In addition, the task force found that while current evidence suggests one-step screening using more inclusive criteria may be associated with better outcomes compared with standard (two-step) criteria, the results from ongoing trials will provide more evidence.
While screening tests were considered “reasonably accurate” for identifying patients who did not need to proceed to a diagnostic test as part of a two-step strategy, they also were considered “likely not sufficient” to diagnose gestational diabetes at this time.
The evidence review found that treatment of gestational diabetes at or after 24 weeks of gestation was associated with decreased risk of primary cesarean deliveries and preterm deliveries, but was not associated with reduced preeclampsia, reduced risk of gestational hypertension, total cesarean deliveries, emergency deliveries, induction of labor or maternal birth trauma.
For fetal/neonatal outcomes, treatment of gestational diabetes at or after 24 weeks of gestation was associated with reduced risk of shoulder dystocia, macrosomia, large-for-gestational-age infants, birth injury and admission to the neonatal ICU.
Finally, the task force stated that the evidence on harms of treatment was somewhat limited but did not indicate serious adverse effects, although results from one study indicated that gestational diabetes diagnosis and labeling might be associated with higher rates of cesarean delivery.
The task force noted in its evidence review that some ethnic minority groups are at increased risk for gestational diabetes and its long-term consequences. While evidence comparing the accuracy or effects of treatment based on race/ethnicity were limited, results from one large treatment trial found no subgroup effects, and there was no indication, based on the evidence in the review, that findings would differ in racial or ethnic groups.
“Gestational diabetes is increasing as obesity, older age during pregnancy and other risk factors become more common among pregnant people,” added task force member Michael Cabana, M.D., M.A., M.P.H. “More research is needed on the accuracy and effectiveness of screening for gestational diabetes before 24 weeks and whether earlier screening could be beneficial for some pregnant people with risk factors.”
The USPSTF has published several recommendations related to pregnancy and the prevention of gestational diabetes. These include recommendations on
The AAFP will review the USPSTF's draft recommendation statement and supporting evidence and will provide comments to the task force. The Academy will release its own recommendation on the topic after the task force finalizes its guidance.