Endocrine Abstracts

Introduction: Glycemic control has a major effect on fetal growth in women with type 1 diabetes mellitus (DM1), worse control leading to increased growth (large for gestational age (LGA) or very large for gestational age (VLGA) fetus). Current guidelines promote strict control (HbA1c ≤ 48 mmol/mol) before and during pregnancy. Continuous glucose monitoring (CGM) has been instrumental in achieving this goal. We performed a retrospective chart review of pregnancy outcomes in DM1 to assess Outcome and CGM-data in well-controlled women with DM1.

Methods: Forty-eight pregnancies in 25 women were identified between 2016–2019; 19 women with a singleton pregnancy met the inclusion criterion of HbA1c ≤ 48 mmol/mol in first and third trimester. In 8 women there were insufficient CGM-data: final CGM-study group of 11 women. LGA was defined as fetal weight > 90th and VLGA > 97.7th percentile. CGM-data were studied during 4 periods: 4–8 weeks gestation, 18–22 weeks, 30–34 weeks and last 8 days before delivery. Target range 3.5–7.8 mmol/l. Time in range (TIR), time below range (TBR) and time above range (TAR) were calculated.

Results: In the group of 19 women with adequate control, LGA (both LGA and VLGA) in 36.8%; simple LGA 15.7%, VLGA 21.1%.In none of the pregnancies congenital malformations were seen. Women with a VLGA child were significantly older (P < 0.03), had higher BMI (P < 0.02) and longer duration of DM1 (P < 0.02). In women with normal growth fetus, LGA or VLGA, TIR was 64.1%, 63.6% and 58.5%; TAR: 24.4, 34.4 and 39.6%; TBR: 4.0, 2.2 and 2.1. Classic multivariate logistic regression analysis did not show statistical significance.

Conclusion: Our data show that current implementation of advanced technology did not have a great effect on fetal growth parameters. Mean TIR was below the recommended level in the newest guideline published in Diabetes Care in June 2019. Apparently, adaptation of endocrine care and counselling strategies are needed for improvement in outcome with technology.