Utility of routine screening fetal echocardiogram in pregnancies conceived by in vitro fertilization

Objective: To study the incidence and clinical significance of congenital heart defects (CHDs) detected by fetal echocardiography in pregnancies conceived by in vitro fertilization (IVF).

Design: Cohort study comparing a prospectively maintained database of all fetal echocardiograms from 2012 to 2018 and pooled data from the Connecticut Birth Defects Registry and statewide hospital discharge data.

Setting: Large tertiary care center.

Patient(s): A total of 181,749 live births and 9,252 fetal echocardiograms were analyzed. Fetal echocardiograms in patients with a previous child with a CHD, a family history of CHD, medication exposure, diabetes, anomaly in previous pregnancy, cardiac or other abnormality noted on previous ultrasound, or monochorionic twins were excluded from the final analysis.

Intervention(s): Treatment with IVF.

Main outcome measure(s): Incidence of CHD and odds ratios with 95% confidence intervals (CIs). Infant outcomes for cases of CHD were evaluated for clinically significant disease, defined a priori as disease requiring any medical or surgical intervention or continued follow-up with pediatric cardiology.

Result(s): Fetal echocardiography was performed in 2,230 IVF pregnancies, of which 2,040 were without other known risk factors for CHD. The mean gestational age at the time of fetal echocardiography was 22.2 ± 1.4 weeks. The odds ratio for CHD in the IVF group compared with statewide population rates was 1.4 (95% CI 0.9-2.1). CHD was diagnosed in 26 fetuses, of which 21 were clinically insignificant ventricular septal defects. One fetal echocardiogram was concerning for pulmonary stenosis that was not present at birth. Four defects were clinically significant, indicating that 510 fetal echocardiograms were performed for every diagnosis of one clinically significant CHD in the IVF group.

Conclusion(s): The incidence of CHD in IVF pregnancies without other risk factors is not significantly different from baseline population rates, and most CHDs diagnosed by fetal echocardiography in this group are clinically insignificant. Routine screening with fetal echocardiography in all IVF pregnancies provides limited utility beyond routine prenatal care and need not be recommended without the presence of other risk factors.