Continuous subcutaneous insulin infusion vs multiple daily injections in pregnant women with type 1 diabetes mellitus: a systematic review and meta-analysis of randomised controlled trials and observational studies

Background Randomised controlled trials (RCTs) have shown an advantage of continuous subcutaneous insulin infusion (CSII) over multiple daily injections (MDI) in the general type 1 diabetes mellitus (T1DM) population. RCT data on T1DM management in pregnancy remain limited. Objective We performed a systematic review of both RCTs and non-RCTs evaluating CSII vs MDI in T1DM-complicated pregnancy. Study design Electronic databases were searched for studies comparing CSII with MDI in T1DM-complicated pregnancy. Methods A meta-analysis provided point estimates with 95% confidence intervals (CI). Continuous outcomes were reported as weighted mean differences (WMD) or standardised mean differences (SMD), and dichotomous data as relative risk (RR). Results The search identified 47 studies, including 43 non-RCTs, reporting on 7824 pregnancies. The meta-analysis showed a lower HbA1c level with CSII vs MDI in the first trimester (WMD: −0.45%; 95%CI: −0.62, −0.27). This difference decreased in subsequent trimesters. Compared to MDI, therapy with CSII resulted in higher gestational weight gain (GWG) (WMD: 1.02 kg; 95%CI: 0.41, 1.62), and lower daily insulin dose requirements in the first (SMD: −0.46; 95%CI: −0.68, −0.24) and subsequent trimesters. Moreover, infants from the CSII group were more likely to be large for gestational age (LGA) (RR: 1.16; 95%CI: 1.07, 1.24) and less likely to be small for gestational age (SGA) (RR: 0.66; 95%CI: 0.45; 0.97). Conclusions In T1DM-complicated pregnancy, CSII compared to MDI therapy resulted in better first trimester glycaemic control; this difference decreased in subsequent trimesters. CSII therapy was associated with lower insulin requirements, higher GWG and altered risk for infants being LGA and SGA.