Importance: Fetuses in women with gestational diabetes (GD) compared with those without GD show evidence of subclinical cardiac functional and morphological changes. However, it is uncertain whether glycemia or the adverse maternal underlying risk factor profile is the main driver for fetal cardiac remodeling.
Objective: To assess cardiac morphology and function at midgestation in fetuses of mothers prior to development of GD and compare them with those of unaffected controls.
Design, setting, and participants: During this prospective nonintervention screening study at 19 to 23 weeks' gestation, fetal cardiac morphology and function were assessed in all participants. Pregnancy complications were obtained from the medical records of the women. Fetal cardiac morphology and function were assessed in all participants at Harris Birthright Research Institute at King's College Hospital, London, United Kingdom. Participants included pregnant women with singleton pregnancy who attended their routine fetal ultrasound examination at midgestation and agreed to participate in the Advanced Cardiovascular Imaging Study in pregnancy.
Main outcome and measures: Comparison of fetal cardiac morphology and function between mothers who subsequently developed GD and those who did not develop GD.
Methods: This was a prospective nonintervention screening study of 5620 women with singleton pregnancies at 19 to 23 weeks' gestation. Conventional and more advanced echocardiographic modalities, such as speckle tracking, were used to assess fetal cardiac function in the right and left ventricle. The morphology of the fetal heart was assessed by calculating the right and left sphericity index.
Results: The 5620 included patients had a mean age of 33.6 years. In 470 cases, the women were diagnosed with GD after the midgestation echocardiographic assessment (8.4%). Women with GD, compared with the non-GD group, were older, had higher BMI, higher prevalence of family history of diabetes, non-White ethnicity, chronic hypertension, and GD in a previous pregnancy. In fetuses of the GD group compared with the non-GD group, there was mild increase in interventricular millimeter thickness (0.04; 95% CI, 0.03-0.06 mm) and left atrial area (0.04; 95% CI, 0.04-0.05), whereas left and right functional indices were comparable between groups with the exception of left ventricular ejection fraction, which was marginally improved in the GD group (0.02; 95% CI, 0.03-0.03).
Conclusions and relevance: This study demonstrates that prior to development of GD, there was mild alteration in fetal cardiac morphology without affecting cardiac function. This suggests that the adverse maternal risk factor profile and not only the glycemia might contribute to cardiac remodeling noted in fetuses of women with GD.