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.