Continuous subcutaneous insulin infusion versus multiple daily injections of insulin for pregnant women with diabetes
Abstract
Background
Diabetes results in a rise in blood glucose above normal physiological levels; if untreated this may cause damage to many systems including the cardiovascular and renal systems. Pregnancy leads to a physiological resistance to 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 method of insulin administration is the continuous subcutaneous insulin infusion pump (CSII).
Objectives
To compare CSII with MDI of insulin for pregnant women with diabetes.
Search methods
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2011).
Selection criteria
Randomised trials comparing CSII with MDI for pregnant women with diabetes.
Data collection and analysis
Three review authors independently assessed studies and two review authors extracted data. Disagreements were resolved through discussion with the third author.
Main results
We included five trials with 153 women and 154 pregnancies.
There was no significant difference in either of the primary outcomes; macrosomia (birthweight greater than 4000 g) (risk ratio (RR) 3.20, 95% confidence interval (CI) 0.14 to 72.62; two trials, 61 pregnancies) and operative birth, caesarean birth being the only outcome reported (RR 1.09, 95% CI 0.66 to 1.77; three trials, 71 pregnancies).
There was an increase in mean birthweight associated with CSII compared with MDI of borderline significance (mean difference (MD) 220.56 g, 95% CI ‐2.09 g to 443.20 g; two trials, 61 pregnancies, P = 0.05). However, the large CI and the lack of a significant difference in macrosomia rate, suggests uncertainty of effect and a clinically insignificant difference. 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 included. No significant differences were found in perinatal mortality (RR 2.33, 95% CI, 0.38 to 14.32; three trials, 71 pregnancies), fetal anomaly (RR 1.07, 95% CI, 0.07 to 15.54; two trials 61 pregnancies), maternal hypoglycaemia (RR 3.00, 95% CI 0.35 to 25.87; two trials, 61 pregnancies) or maternal hyperglycaemia (RR 7.00, 95% CI, 0.39 to 125.44; two trials, 61 pregnancies) or small‐for‐gestational age (average RR 1.40, 95% CI 0.10 to 18.71; two trials, 61 pregnancies, random‐effects analysis T2 = 1.10, I2 = 31%).
Authors' conclusions
There is little evidence to support the use of one particular form of insulin administration over another for pregnant women with diabetes. The data are few, there are only a small number of trials appropriate for meta‐analysis, a small number of women included and questionable generalisability of the trial population. Conclusions cannot be made from the available data. Well‐designed randomised trials are needed. These trials should be adequately powered to assess the effect of CSII versus MDI on important outcomes for women with diabetes and their infants.
PICOs
Plain language summary
Continuous subcutaneous insulin infusion versus multiple daily injections of insulin for pregnant women with diabetes
There is insufficient evidence on the effects of different ways of administering insulin for pregnant women with diabetes.
Diabetes is a condition in which glucose (sugar) in the blood is too high because the body is resistant to the effects of insulin or not enough insulin is produced. Insulin is a hormone produced by the pancreas; it enables glucose to enter the cells where it is used as fuel by the body. Controlling blood sugar levels is important because a too high or too low blood sugar can affect the brain and other organs of the body. It is also very important to control the blood sugar of pregnant women who have diabetes because poor blood sugar control increases the risk of abnormalities in the baby, increases the chance of miscarriage or stillbirth and can also lead to large babies (macrosomia) who may then have a difficult birth. Traditionally insulin injections are given as multiple daily injections (MDI) but an alternative way to give insulin is as a continuous infusion by a small pump via a fine tube placed under the skin (CSII). It has been suggested that CSII may result in a more stable blood glucose, and so a lower chance of too high or too low blood sugar level happening, which may benefit the baby as well as the mother. There may be adverse effects too. This review of trials looked at CSII compared with MDI for administering insulin to pregnant women with diabetes. Five trials involving 153 women and 154 pregnancies were included. The trials provide insufficient information to be able to say which method of insulin administration is better for the woman or her infant. Further research is needed.
