Risk factors determine need for fetal echocardiogram in IVF pregnancies

In vitro fertilization (IVF) pregnancies only need fetal echocardiogram monitoring if other risk factors are present, according to a recent study.

A study published in the journal Fertility and Sterility reports that IVF pregnancies do not require routine fetal echocardiogram monitoring unless there are other risk factors, as data shows the incidence of congenital heart defects (CHD) does not differ between IVF and baseline population rates. The study was conducted by Kurt R Bjorkman, MD, and colleagues. Bjorkman is 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, Iowa.

Researchers performed a cohort study where they compared a prospectively maintained database from 2012 to 2018 of all fetal echocardiograms and collected data from both Connecticut’s statewide hospital registry and from the Connecticut Birth Defects Registry.1 The study’s setting was a large tertiary care center. Researchers examined 181,749 live births and 9,252 fetal echocardiograms. They excluded fetal echocardiograms from the final analysis of pregnancies that were complicated by monochorionic twins, cardiac, or other abnormality noted on previous ultrasound; an anomaly in previous pregnancy, diabetes, patients with a previous child with a CHD, a family history of CHD and medication exposure.1

Researchers reported 2,230 IVF pregnancies had fetal echocardiography performed. Of these, 2,040 had no known risk factors for CHD. Researchers reported a mean gestational age at the time of the screening of 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),” study authors reported.1

In the more than 2,000 fetuses scanned, 26 fetuses had a CHD diagnosis, with 21 being clinically insignificant ventricular septal defects, researchers said.1 One fetal echocardiogram showed pulmonary stenosis, which was not present at birth, and researchers reported only 4 of these were clinically significant defects.

Bjorkman and colleagues said the results of the study showed that rates of CHD among IVF pregnancies that have no other risk factors are not different than the baseline population. In addition, most CHD diagnoses in this group were found to be clinically insignificant. “Routine screening with fetal echocardiography in all IVF pregnancies provides limited utility beyond routine prenatal care,” and “that in otherwise low-risk pregnancies, IVF conception alone may not be a strong enough indication for fetal echocardiogram,” researchers concluded.1

In an interview with Contemporary OB/GYN®, Bjorkman said the study’s findings are significant, because “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. 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 to the control and is not different than other published rates of CHD in the general population.”

He added that most of the CHD detected in IVF pregnancies was not clinically significant, as “most were ventricular septal defects that either resolved spontaneously prior to birth or shortly after and required no further follow-up. 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,” he said.

For steps to take beyond the study, Bjorkman said this study gives reason to re-evaluate current recommendations for screening with fetal echo in all pregnancies conceived by IVF. “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. With this, it may be prudent to be more selective in choosing to only screen IVF pregnancies that have additional risk factors for CHD,” Bjorkman noted.

Reference

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 ahead of print, 2021 Jun 28. Fertil Steril. 2021;S0015-0282(21)00418-0. doi:10.1016/j.fertnstert.2021.04.035