P19.02: The effects of maternal diabetes on fetal heart function: a systematic review

Objectives The incidence of diabetes in pregnancy is rising. Growing evidence shows not only an association with structural anomalies of the fetal heart, but also functional changes. This review aims to give an overview of the possible effects of diabetes on fetal cardiac function. Methods Databases were searched using the terms ‘diabetes’, ‘cardiac’ and ‘fetus’. All studies comparing fetal cardiac function in diabetic pregnancies with normal pregnancies were selected. Articles were reviewed for diabetes type, therapy, glycemic control and ultrasound technique. Ultrasound data describing hypertrophy, diastolic, systolic or overall function were extracted. Results 28 articles were included, representing data of 1487 patients and 1782 controls. Of the cases 808 had gestational diabetes (GDM), 602 had pre‐existing diabetes (PDM) and 77 unknown. Ultrasound examination was performed in the 1st, 2nd or 3rd trimester in 3, 16 and 23 studies respectively. Cardiac hypertrophy, reported in 15 studies (n=919), was significantly more prevalent in diabetic pregnancy in 13/15 (87%) studies. Diastolic and systolic function was measured in 19 (n=1138) and 18 studies (n=1114) respectively. Diastolic function was significantly impaired in 14/19 (74%). Systolic function was decreased in 6/18 (33%) studies. 10 studies (n=441) measured overall function of which 8 (80%) found significant impairment. Forest plots of most used parameters – interventricular septum (IVS, n=648) and myocardial performance index (MPI, n=590) – showed significant increased IVS and MPI in diabetic group, with a mean difference of 0.73 [0.66, 0.79] (p<0.01) and 0.04 [0.04, 0.05] (p<0.01) respectively. Conclusions Our review shows that diabetes in pregnancy can cause fetal cardiac hypertrophy and impaired cardiac function. This effect is more pronounced in PDM, but GDM also causes significant functional impairment. The effect is most visible in the 3rd trimester. Future research should focus on clinical importance of these findings for neonatal outcome.