Continuous subcutaneous insulin infusion versus multiple daily injections of insulin for pregnant women with diabetes

Background Diabetes causes a rise in blood glucose above normal physiological levels causing damage to many systems including the cardiovascular and renal systems. Pregnancy causes a physiological reduction in insulin action; for those women who have pre-gestational diabetes, this results in an increasing insulin requirement. There are several methods of administering insulin. Conventionally, insulin has been administered subcutaneously, formally referred to as intensive conventional treatment, but now more usually referred to as multiple daily injections (MDI). An alternative insulin administration method is the continuous subcutaneous insulin infusion pump (CSII). Objectives To compare continuous subcutaneous insulin infusion with MDI of insulin for pregnant women with diabetes. Search strategy We searched the Cochrane Pregnancy and Childbirth Group's Trials Register ( November 2006). Selection criteria Randomised controlled trials comparing CSII with MDI for pregnant women with diabetes. Data collection and analysis Three authors independently assessed studies and extracted data. Main results Two studies ( 60 women with 61 pregnancies) were included. There was a significant increase in mean birthweight associated with CSII as opposed to MDI ( weighted mean difference 220.56, 95% confidence interval (CI) -2.09 to 443.20; two trials, 61 participants). However, taking into consideration the lack of significant difference in rate of macrosomia ( birthweight greater than 4000 g) ( relative risk (RR) 3.20, 95% CI 0.14 to 72.62; two trials, 61 participants), this is not viewed by the authors as clinically significant. No significant differences were found in any other outcomes measured, which may reflect the small number of trials suitable for meta-analysis and the small number of participants in the included studies. No significant differences were found in perinatal mortality (RR 2.00, 95% CI 0.20 to 19.91), fetal anomaly (RR 1.07, 95% CI 0.07 to 15.54), maternal hypoglycaemia (RR 3.00, 95% CI 0.35 to 25.87) or maternal hyperglycaemia (RR 7.00, 95% CI 0.39 to 125.44). Authors' conclusions There is a dearth of robust evidence to support the use of one particular form of insulin administration over another for pregnant women with diabetes. The data are limited because of the small number of trials appropriate for meta-analysis, small study sample size and questionable generalisability of the trial population. Conclusions cannot be made from the data available and therefore a robust randomised trial is needed. The trial should be adequately powered to assess the efficacy of continuous subcutaneous insulin infusion versus multiple daily injections in terms of appropriate outcomes for women with diabetes.