Effectiveness of gestational diabetes treatment: A systematic review with quality of evidence assessment

AIMS: To evaluate the effectiveness of gestational diabetes (GDM) treatment compared to usual antenatal care, in the prevention of adverse pregnancy outcomes. Additionally, to assess the quality of the evidence to support GDM treatment according to GRADE guidelines. METHODS: Fourteen electronic databases and reference lists of relevant literature were searched for articles published from inception to February, 2012. Controlled clinical trials comparing GDM treatment to usual antenatal care were included. Independent extraction of articles was done by two authors using predefined data fields. RESULTS: Seven trials involving 3157 women were included. We found high quality evidence that treatment of GDM reduces macrosomia (RR=0.47; 95% CI, 0.34-0.65; NNT=11.4) and large for gestational age birth (RR=0.57; 95% CI, 0.47-0.71; NNT=12.2); moderate quality evidence that treatment reduces preeclampsia (RR=0.61; 95% CI, 0.46-0.81; NNT=21.0) and hypertensive disorders in pregnancy (RR=0.64; 95% CI, 0.51-0.81; NNT=18.1); and low quality evidence that treatment reduces shoulder dystocia (RR=0.41; 95% CI, 0.22-0.76; NNT=48.8). No statistically significant reduction was seen for caesarean section. No increase in small for gestational age or preterm birth was found. CONCLUSIONS: Treatment of GDM is effective in reducing macrosomia (high quality evidence), preeclampsia and shoulder dystocia.