Background

Gestational diabetes mellitus (GDM) is a form of diabetes that occurs in pregnancy. Although GDM usually resolves following birth, it is associated with significant morbidities for mother and baby both perinatally and in the long term. There is strong evidence to support treatment for GDM. However, there is little consensus on whether or not screening for GDM will improve maternal and infant health and if so, the most appropriate protocol to follow.

Objectives

To assess the effects of different methods of screening for gestational diabetes mellitus and maternal and infant outcomes.

Search strategy

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (April 2010).

Selection criteria
Randomised and quasi-randomised trials evaluating the effects of different methods of screening for gestational diabetes mellitus.

Data collection and analysis

Two review authors independently conducted data extraction and quality assessment. We resolved disagreements through discussion or through a third author.

Main results

We included four trials involving 3972 women were included in the review. One quasi-randomised trial compared risk factor screening with universal or routine screening by 50 g oral glucose challenge testing. Women in the universal screening group were more likely to be diagnosed with GDM (one trial, 3152 women, risk ratio (RR) 0.44 95% confidence interval (CI) 0.26 to 0.75). Infants of mothers in the risk factor screening group were born marginally earlier than infants of mothers in the routine screening group (one trial, 3152 women, mean difference -0.15 weeks, 95% CI -0.27 to -0.53).

The remaining three trials evaluated different methods of administering a 50 g glucose load. Two small trials compared glucose monomer with glucose polymer testing, with one of these trials including a candy bar group. One trial compared a glucose solution with food. No differences in diagnosis of GDM were found between each comparison. Overall, women drinking the glucose monomer experienced fewer side effects from testing than women drinking the glucose polymer (two trials, 151 women, RR 2.80, 95% CI 1.10 to 7.13). However, we observed high heterogeneity between the trials for this result (I2 = 61%).

Authors' conclusions

There was insufficient evidence to determine if screening for gestational diabetes, or what types of screening, can improve maternal and infant health outcomes.