Comparison of the Screening Tests for Gestational Diabetes Mellitus between “One-Step” and “Two-Step” Methods among Thai Pregnant Women

Abstract EN

Objective.

To compare the prevalence and pregnancy outcomes of GDM between those screened by the “one-step” (75 gm GTT) and “two-step” (100 gm GTT) methods.

Methods.

A prospective study was conducted on singleton pregnancies at low or average risk of GDM.

All were screened between 24 and 28 weeks, using the one-step or two-step method based on patients’ preference.

The primary outcome was prevalence of GDM, and secondary outcomes included birthweight, gestational age, rates of preterm birth, small/large-for-gestational age, low Apgar scores, cesarean section, and pregnancy-induced hypertension.

Results.

A total of 648 women were screened: 278 in the one-step group and 370 in the two-step group.

The prevalence of GDM was significantly higher in the one-step group; 32.0% versus 10.3%.

Baseline characteristics and pregnancy outcomes in both groups were comparable.

However, mean birthweight was significantly higher among pregnancies with GDM diagnosed by the two-step approach (3204 ± 555 versus 3009 ± 666 g; p=0.022).

Likewise, the rate of large-for-date tended to be higher in the two-step group, but was not significant.

Conclusion.

The one-step approach is associated with very high prevalence of GDM among Thai population, without clear evidence of better outcomes.

Thus, this approach may not be appropriate for screening in a busy antenatal care clinic like our setting or other centers in developing countries.