Risk factors determine need for fetal echocardiogram in IVF pregnancies

In vitro fertilization (IVF) pregnancies do not require routine fetal echocardiogram monitoring unless other risk factors are present, as data show the incidence of congenital heart defects (CHD) do not differ between IVF and baseline population rates, according to study findings published in Fertility and Sterility.

A cohort study, conducted by Kurt R. Bjorkman, MD, and colleagues, compared a prospectively maintained database of all fetal echocardiograms from 2012 to 2018 and included data collected from Connecticut’s statewide hospital registry and the Connecticut Birth Defects Registry. The investigators examined 181,749 live births and 9252 fetal echocardiograms. The final analysis excluded fetal echocardiograms of pregnancies that were complicated by the following: an anomaly in previous pregnancy, cardiac or other abnormality as noted on ultrasound, diabetes, medication exposure, monochorionic twins, and patients who had a previous child with CHD or a family history of CHD.

A fetal echocardiogram was performed in 2230 IVF pregnancies. Of these, 2040 had no known risk factors for CHD. Investigators reported a mean gestational age of 22.2 ± 1.4 weeks at the time of the screening. “The odds ratio for CHD in the IVF group compared with statewide population rates was 1.4 (95% CI, 0.9-2.1),” the investigators reported.

Of more than 2000 fetuses scanned, 26 fetuses had a CHD diagnosis. However, 21 cases were clinically insignificant ventricular septal defects, according to study findings.One fetal echocardiogram showed pulmonary stenosis, which was not present at birth. Only 4 of these were clinically significant defects.

Rates of CHD among IVF pregnancies that have no other risk factors are not different than the baseline population, the investigators concluded. “Routine screening with fetal echocardiography in all IVF pregnancies provides limited utility beyond routine prenatal care…in otherwise low-risk pregnancies, IVF conception alone may not be a strong enough indication for fetal echocardiogram,” the investigators said.

In an interview with Contemporary OB/GYN®, Bjorkman, a pediatrician from the Department of Pediatrics at the Yale School of Medicine in New Haven, Connecticut, and the section of pediatric cardiology at the Department of Pediatrics at the University of Iowa Hospitals and Clinics in Iowa City, said the study’s findings are significant.

“Currently, the American Heart Association, the American Institute of Ultrasound in Medicine, and the American Society of Echocardiography recommend consideration of fetal echo in all IVF-conceived pregnancies,” he said. “The most significant finding of this study was that in following these guidelines, the incidence of CHD present at birth—as detected by fetal echo in pregnancies without other risk factors for CHD—was 0.9%, which has an odds ratio of 0.97 (95% CI, 0.6 – 1.5) when compared [with] the control and is not different than other published rates of CHD in the general population.”

In addition, Bjorkman said that most of the CHD detected in IVF pregnancies were not clinically significant. “Most were ventricular septal defects that either resolved spontaneously prior to birth or shortly after, and required no further follow-up,” he said. “By following current guidelines, the rate of clinically significant congenital heart defects detected by fetal echo in pregnancies without other risk factors was only 0.2%. This equates to 510 fetuses scanned to detect 1 clinically significant congenital heart defect.”

Bjorkman added, “Given the high number of scans needed to be completed to detect one significant CHD, the recommendation for screening all pregnancies conceived by IVF carries with it a significant financial and time-consuming burden to the medical system, and likely significant additional stress to many pregnant patients for each diagnosis.”

These findings give reason to reevaluate current recommendations for screening with fetal echocardiogram in all pregnancies conceived by IVF and to be more selective in choosing to only screen IVF pregnancies that have additional risk factors for CHD, Bjorkman said.

Reference

1. Bjorkman KR, Bjorkman SH, Ferdman DJ, Sfakianaki AK, Copel JA, Bahtiyar MO. Utility of routine screening fetal echocardiogram in pregnancies conceived by in vitro fertilization. Published online June 28, 2021. Fertil Steril. 2021;S0015-0282(21)00418-0. doi:10.1016/j.fertnstert.2021.04.035