Assessment of fetal cardiac function in pregnant women with anemia: prospective case-control study.

Objective: To compare fetal cardiac function in pregnant women with iron deficiency anemia (IDA) vs healthy pregnant controls.

Methods: This was a single-center, prospective, case-control study conducted in a tertiary hospital between November 2022 and September 2023. Women diagnosed with IDA who attended as outpatients at the pregnancy follow-up clinic at 30-34 weeks' gestation or who were hospitalized for intravenous iron treatment owing to profound anemia were included. The control group consisted of randomly selected gestational-age-matched pregnant women with no obstetric complications or comorbidities and who did not have anemia. Patients underwent two-dimensional imaging, followed by pulsed-wave Doppler and M-mode and tissue Doppler imaging (TDI) to evaluate fetal cardiac function. A fetal cardiac score was calculated using systolic, diastolic and global hemodynamic function parameters, and was compared between patients with IDA and those without. The fetal cardiac score was also assessed according to the severity of anemia in the IDA group.

Results: A total of 150 patients, comprising 50 patients with IDA and 100 healthy pregnant women at 30-34 weeks' gestation, were included in the study. Of the patients with IDA, 20 had mild, 18 had moderate and 12 had severe anemia. The fetal myocardial performance index and isovolumetric relaxation time were significantly higher in the IDA group compared with the control group (P < 0.0001 for both), while isovolumetric contraction time was similar. Among the fetal tricuspid and mitral valve diastolic parameters, the E, A and E/A values were significantly lower in the IDA group (P < 0.05 for all). Mitral (MAPSE) and tricuspid (TAPSE) annular plane systolic excursions were significantly lower in the IDA group (P < 0.05 for both). The IDA group also had significantly lower values for the TDI parameters mitral and tricuspid E', A', S' and E'/A' ratio and a significantly higher E/E' ratio (P < 0.05 for all). Among the IDA subgroups, a significant decrease was observed in the tricuspid and mitral A, E and E/A ratio in fetuses whose mothers had severe anemia (P = 0.001). M-mode Doppler analysis revealed significantly lower fetal TAPSE and MAPSE in the patient group with severe maternal anemia (P = 0.001 for both). According to the subgroup comparison of TDI findings, the fetuses of mothers with severe anemia had significantly lower tricuspid and mitral E', A', S' and E'/A' ratio values and a significantly higher E/E' ratio (P < 0.05 for all). The fetal cardiac score was significantly higher in the maternal IDA group compared with the control group (P < 0.001). A significant negative correlation was found between maternal hemoglobin level and fetal cardiac score (P < 0.001).

Conclusions: We observed differences in fetal systolic and diastolic cardiac function in pregnancies with maternal IDA. Fetal cardiac function was affected more among patients with severe anemia. This study found an increased E/E' ratio in the fetuses of pregnant women with IDA, suggesting decreased fetal heart maturation. Prenatal fetal cardiac evaluation, especially in women with severe anemia, can facilitate a more seamless transition to the postnatal period for these newborns. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.