primary outcome:
Techniques of monitoring blood glucose during pregnancy for women with pre‐existing diabetes
Continuous glucose monitoring may reduce the composite outcome of hypertensive disorders of pregnancy (risk ratio (RR) 0.58, 95% confidence interval (CI) 0.39 to 0.84; 2 studies, 384 women; low‐quality evidence,Analysis 1.1), although this did not translate into a clear reduction for pre‐eclampsia, see secondary outcomes below.Due to moderate heterogeneity, we used random‐effects analysis for caesarean section and there was no clear reduction in rate of caesarean section (average RR 0.94, 95% CI 0.75 to 1.18; 3 studies, 427 women; I2 = 41%; moderate‐quality evidence, Analysis 1.2), or large‐for‐gestational age (average RR 0.84, 95% CI 0.57 to 1.26; 3 studies, 421 women; I2 = 70%; low‐quality evidence, Analysis 1.3). There was not enough evidence to assess perinatal mortality (RR 0.82, 95% CI 0.05 to 12.61, 71 infants, 1 study, Analysis 1.4, low‐quality evidence) or the composite of neonatal mortality or morbidity (RR 0.80, 95% CI 0.61 to 1.06; 1 study, 200 women) as the evidence was based on single studies of low‐quality.Neurosensory disability
This outcome was not reported.It is uncertain whether self‐monitoring reduces the risk of caesarean section (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.40 to 1.49, 1 study, 28 women, Analysis 2.1, very low‐quality evidence) (Varner 1983). Varner 1983 also reported perinatal mortality and it was too small to show any differences between groups (perinatal mortality: RR 3.00, 95% CI 0.13 to 67.91, 1 study, 28 infants, very low‐quality evidence, Analysis 2.2).Hypertensive disorders of pregnancy, large‐for‐gestational age, neonatal mortality and morbidity composite and neurosensory disability were not reported in either study.This study of 100 women did not report on the composite outcome, hypertensive disorders of pregnancy. It reported pre‐eclampsia and hypertension in pregnancy, but as separate outcomes.The results were uncertain for caesarean section (RR 0.96, 95% CI 0.65 to 1.44, Analysis 3.2, very low‐quality evidence), and the sample size was too small to assess perinatal mortality (RR 0.85, 95% CI 0.05 to 13.24, Analysis 3.3, very low‐quality evidence).Large‐for‐gestational age, mortality or morbidity composite, and neurosensory disability were not reported.In one study of 61 women (61 infants), it is uncertain whether there is any difference between pre‐prandial and post‐prandial glucose monitoring for caesarean section (RR 1.45, 95% CI 0.92 to 2.28, Analysis 4.1, very low‐quality evidence), large‐for‐gestational age (RR 1.16, 95% CI 0.73 to 1.85; Analysis 4.2, very low‐quality evidence) and perinatal mortality (RR 2.91, 95% CI 0.12 to 68.66, Analysis 4.3, very low‐quality evidence).The study did not report the composite outcomes, hypertensive disorders of pregnancy (including pre‐eclampsia, pregnancy‐induced hypertension, eclampsia), mortality or morbidity composite, or neurosensory disability.Again, it is uncertain from one study (Dalfrà 2009) whether there is any difference between automated telemedicine monitoring and conventional monitoring for caesarean section (RR 0.96, 95% CI 0.62 to 1.48, 1 study, 32 women, Analysis 5.1, very low‐quality evidence) and the composite of neonatal mortality or morbidity (RR 1.18, 95% CI 0.53 to 2.62, 1 study, 32 infants, Analysis 5.2).di Biase 1997 and Wojcicki 2001 did not report these primary outcomes, and none of the studies contributing data to this comparison reported hypertensive disorders of pregnancy, large‐for‐gestational age, perinatal mortality (stillbirth and neonatal mortality), and neurosensory disability.It is uncertain whether constant CGM makes any difference to rates of caesarean section (RR 0.77, 95% CI 0.33 to 1.79, 1 study, 25 women, very low‐quality evidence, Analysis 6.1). Other primary outcomes were not reported (hypertensive disorders of pregnancy, large‐for‐gestational age, perinatal mortality (stillbirth and neonatal mortality), mortality or morbidity composite, and neurosensory disability).