NEW ORLEANS — Most obstetrical care providers agree that at-risk women should undergo early screening for gestational diabetes mellitus, and the majority use the 50-g, 1-hour oral glucose challenge test, results from a single-center survey showed.
“Our data suggest early screening detects a significant proportion of women with GDM [gestational diabetes mellitus],” Dr. Kimberly K. Vesco of the center for health research at Kaiser Permanente Northwest, Portland, Ore., reported in a poster at the annual scientific sessions of the American Diabetes Association. “Formal protocols for early screening of at-risk women should be established and evaluated to determine whether they lead to improvement in early screening and detection of GDM.”
Although both the American College of Obstetricians and Gynecologists and the ADA recommend screening pregnant women at risk for diabetes at the first prenatal visit, “neither organization specifies what lab test to use for early screening, e.g., fasting plasma glucose [FPG]; the 50-g, 1-hour oral glucose challenge test [OGCT]; or both,” wrote the researchers, who said they had no disclosures to report.
To find out how and why clinicians screen for diabetes in early pregnancy, the researchers surveyed 92 obstetrical care providers at Kaiser Permanente Northwest in 2007 about their first- and second-trimester GDM screening practices. They analyzed medical records of women who gave birth there from 2004 to 2006 to determine the prevalence of GDM and the proportion of women with GDM diagnosed before 24 weeks' gestation.
Of 92 clinicians, 62 (67%) returned the survey, including 33 obstetricians, 16 nurse-midwives, and 9 nurse practitioners. Four respondents did not report their degree.
The majority of providers indicated they would order GDM screening for women with a history of GDM (97% in the first trimester vs. 87% in the second trimester), those with a history of delivering a macrosomic infant (82% in the first trimester vs. 77% in the second trimester), and those who are obese (81% in the first trimester vs. 73% in the second trimester).
The 50-g OGCT was the preferred test of respondents for early screening (71% in the first trimester vs. 77% in the second trimester), followed by the FPG test (26% in the first trimester vs. 10% in the second trimester), and a combination of the two tests (8% in the first and second trimesters).
Between 2004 and 2006, 436 women were diagnosed with GDM, for a prevalence of 3.8%. The prevalence was significantly higher among obese women compared with nonobese women (6.7% vs. 2.9%).
Overall, just 4.6% of GDM diagnoses were made before 12 weeks' gestation and 10.9% prior to 24 weeks' gestation. Among obese women with GDM, 5.4% were diagnosed prior to 12 weeks and 14.8% prior to 24 weeks' gestation. In addition, the researchers wrote, “despite the majority of providers indicating that they would screen obese women at the first prenatal visit, the proportion of obese women screened was only 16% prior to 12 weeks and 29% prior to 24 weeks.”
The 50-g, 1-hour OGCT was most commonly used for all study participants (in 75% prior to 12 weeks' gestation, in 90% between 12 and 23 weeks' gestation and in 99.6% at 24 weeks' gestation and beyond), followed by FPG (in 24% prior to 12 weeks' gestation, in 9% between 12 and 23 weeks' gestation, and in 0.4% at week 24 of gestation and beyond) and the 100-g, 3-hour oral glucose tolerance test (in 0.4% prior to 12 weeks' gestation, in 1.2% between 12 and 23 weeks' gestation, and in 0.1% at week 24 of gestation and beyond).