Continuous glucose monitoring in pregnancies with type 1 diabetes: small increases in time-in-range improve maternal and perinatal outcomes.

BACKGROUND: Continuous glucose monitors provide detailed information regarding glycemic control in pregnant patients with type 1 diabetes. Little data have been published examining the association between continuous glucose monitor parameters and perinatal outcomes among gravidas with type 1 diabetes using continuous glucose monitors. OBJECTIVE: This study aimed to examine the association between perinatal outcomes and time-in-range as assessed by continuous glucose monitors used in pregnant individuals with type 1 diabetes. We hypothesized that higher time-in-range would be associated with lower risk of adverse perinatal outcomes. STUDY DESIGN: This multicenter retrospective cohort study included all gravidas with type 1 diabetes using continuous glucose monitors who delivered from 2020 to 2022 at 5 University of California sites. Only those with continuous glucose monitor target range set to 70 to 140 mg/dL (±10 mg/dL) were included. Time-in-range (%) was recorded at 12, 16, 20, 24, 28, and 32 weeks. The primary maternal and neonatal outcomes were preeclampsia and large for gestational age, defined as birthweight ≥95th percentile. Kruskal-Wallis tests were used to compare median time-in-range between those with and without the primary outcomes. Log-binomial regression was used to obtain risk ratios, with adjustment for microvascular disease and years with type 1 diabetes. RESULTS: A total of 91 patients were included. Most used an insulin pump (81%) and did not have diabetic microvascular disease (72%). Median time since diagnosis of type 1 diabetes was 16 years, and median periconception hemoglobin A1c was 6.7%. Compared with those with preeclampsia, normotensive gravidas had significantly higher time-in-range at nearly every time point. A similar pattern was observed for those with normal-birthweight infants compared with large-for-gestational-age infants. On adjusted analyses, every 5-unit increase in time-in-range at 12 weeks was associated with 45% and 46% reductions in the risks of preeclampsia and large for gestational age, respectively (preeclampsia: adjusted risk ratio, 0.55; 95% confidence interval, 0.30-0.99; large for gestational age: adjusted risk ratio, 0.54; 95% confidence interval, 0.29-0.99). CONCLUSION: Higher time-in-range is associated with lower risk of preeclampsia and large for gestational age. This association is observed early in gestation, when each 5-unit increase in time-in-range is associated with ∼50% reduction in the risk of these complications. These findings can be used to counsel patients regarding the risk of pregnancy complications at specific time-in-range values, and to encourage patients that even small improvements in time-in-range can have significant impact on pregnancy outcomes. Larger studies are needed to further explore these findings and to identify optimal time-in-range to reduce perinatal complication rates.

Screening for Cardiovascular Disease in Pregnancy: Is There a Need?

Maternal mortality in the United States has been on the rise. Every year, about 700 women die from pregnancy-related complications. Cardiovascular disease (CVD) accounts for a large majority of pregnancy-related deaths driven by the lack of recognition and delays in diagnosis due to the overlap of normal pregnancy symptoms with those of CVD. Risk factors for CVD including race, advanced maternal age, hypertension, diabetes, obesity, socioeconomic status, and geographic region play an important role in CVD-related deaths. Several risk assessment models are available to stratify women with a known diagnosis of CVD. However, most women who die from CVD during pregnancy or the postpartum period do not have a prior diagnosis of CVD, and cardiomyopathy is an important contributor. The California Maternal Quality Care Collaborative (CMQCC) developed an algorithm to screen all pregnant and postpartum women to allow stratification into low or high risk for CVD. The algorithm has been validated in diverse patient populations. We propose universal CVD screening for all women in the antepartum and postpartum period to identify women at risk and to provide education and awareness for both patients and healthcare providers. This screening tool would work to reduce the increasing rates of severe maternal mortality and morbidity while having a significant impact on healthcare costs in the United States.