Endocrine Abstracts

Background: Pregnancy with type 1 diabetes mellitus (T1DM) carries risks for many adverse outcomes; the most common are large-for-gestational-age neonates (LGA). Proper glycemic control reduces the risk for LGA. However, it occurs in almost 40% of T1DM pregnancies despite of achieving almost normoglycemia. Some studies suggested the contributing role of maternal body mass index (BMI) and glucovariability, but the effect on development of LGA still remains unclear.

Objectives: The aim of this study was to analyse incidence of LGA in planned and well-controlled T1DM pregnancies.

Methods: This prospective study included 42 patients with T1DM who were using continuous glucose monitoring (CGM) from preconception to delivery. Including criteria were preconception counselling, CGM at least 3 months prior to the study, duration of T1DM for at least 1 year, HbA1c < 7.5%, BMI <25 kg/m². Excluding criteria were HbA1c >7.5% and maternal weight gain > 20 kg in the 2^nd and 3^rd trimester. Patients used intermittently scanned CGM and data was analysed once in every trimester. Statistical analysis was performed with IBM SPSS software and data was defined as mean and standard deviation.

Results: In the first, second and third trimester time in range was 54.3±14.3, 62.4± 10.6, 67.5±11.7% respectively. Glucose management indicator was 6.5±0.5, 6.0±0.4, 5.9±0.4% and %coefficient of variation 41.2±7.5, 38.6±5.9, 34.1±6.5% in the first, second and third trimester, respectively. Neonatal birth weight was 3594.3±632.2 grams, birth weight percentile 72.1±28.6 and 45% of neonates were LGA.

Conclusions: In this study we observed improved glycaemic control and decrease of glycemic variability from the first to the third trimester as a result of structured preconception counselling and strict follow-up. However, there was high incidence of LGA despite adequate glycemic control, low glycemic variability and normal BMI. Further studies for defining LGA aetiology in T1DM pregnancies are needed.