National Pregnancy in Diabetes Audit 2021 and 2022 (01 January 2021 to 31 December 2022)

The proportion of pregnant women, with type 1 diabetes, using real-time CGM technology increased from 47% in 2021 to 69% in 2022. This means that data are available for 2,400 type 1 diabetes pregnancies where real-time CGM was used (995 in 2021, 1,445 in 2022). The proportion of women being offered CGM technology (if not already using it) has also increased, such that by 2022 only a minority (8.2%) with type 1 diabetes were not offered CGM technology. The majority of women with early-onset type 2 diabetes (85.8%) were not offered CGM. Although many more women with type 1 diabetes were offered CGM, most pregnant women with both types of diabetes accepted the offer of CGM use (83%). At presentation for antenatal care more women were using intermittently scanned (flash) glucose monitoring systems, but by 28 weeks more were using real-time CGM. The changes in glucose monitoring methods from 2021 to 2022 are notable. During 2021, most women with type 1 diabetes used flash glucose monitoring systems (54.3%), followed by self-monitoring of capillary blood glucose (31.4%) and real-time CGM (13.0%) during early pregnancy. By 2022, most women were using real-time CGM (real-time CGM 69.1%, flash 26.1%, fingerstick self-monitoring 3.6%) during pregnancy (measured at 28 weeks gestation).

Women living in the most deprived quintile were less likely to be using real-time CGM at 28 weeks gestation (25.5% quintile 5 vs 15.5 quintile 1), and significantly less likely to be offered CGM use, with almost half (48.8%) of those living in the 2 most deprived quintiles not offered CGM, compared to less than one-third (30.6%) in the 2 least deprived quintiles. The majority of women with type 1 diabetes are from White ethnic groups (86.4%) with smaller numbers form ethnic minorities (9.9%). Women from White ethnic groups were more likely to use CGM (59.1% used CGM, 40.9% did not) and women from ethnic minorities were less likely to use CGM technology (50.0% used CGM, 48.8% did not). There were also differences in relation to method of insulin delivery with insulin pump users more likely to use CGM (74.4% used CGM, 25.6% did not) compared to women using multiple daily injections (53.3% used CGM, 46.7% did not).^*

During 2021 and 2022, the rates of serious adverse pregnancy outcomes (congenital anomaly, stillbirth and neonatal death) were lower in women using CGM (4.4% vs 6.2%). As congenital anomalies (birth defects) are more strongly associated with maternal glucose levels during early pregnancy, before CGM is usually offered, we also examined the rates of perinatal deaths, which were lower in CGM users (1.7 vs 2.6%).

There were small improvements in maternal glucose among CGM users in early pregnancy, with more pronounced differences during late pregnancy, favouring CGM users across maternal HbA1c categories. Benefits of CGM use were also observed for common obstetric and neonatal complications, including preterm births (39.5% vs 43.9%), large for gestational age birthweight (45.6% vs 53.5%) and neonatal care unit admission (44.8% vs 48.5%). The median length of neonatal hospital stay was 6 days in those who did and did not use CGM. It is likely that more advanced diabetes technology (i.e. hybrid closed-loop systems) will be needed to further improve maternal glucose and neonatal health outcomes in type 1 diabetes.