Irregular fetal heartbeats are relatively common, but a Yale study, the largest of its kind to date, shows these arrhythmias are an indication of serious problems in only a fraction of affected fetuses.
"A skipped or extra beat in a baby's heart rate is reported in about 14 percent of normal healthy neonates," said Joshua Copel, M.D., professor of obstetrics and gynecology at the Yale School of Medicine and an expert in high-risk pregnancies. "But we now know after reviewing our data that there is only a one to two percent chance of finding a problem in the rhythm of the heart that needs to be attended to before or after birth."
The results were published in the April issue of the American Journal of Obstetrics and Gynecology. They were based on a review of 5,566 fetal echocardiograms conducted at the Yale Fetal Cardiovascular Center on 4,838 different fetuses from 1988 through 1997. This is the largest review to date of fetuses with heart rhythm irregularities.
Of the total number of fetuses referred to the unit for irregular heart beats, 614 were found in further testing to have heart arrhythmias. An additional examination showed that of the 614 fetuses, extra heartbeats were recorded in 255, or 42.9 percent, and normal heart rhythms were reported in 330, or 55.4 percent. Significant arrhythmias were seen in 10. And of the 10, two of the fetuses were found to have heart disease.
Copel said he conducted the study to help lessen expectant parents' concerns and to reinforce his approach that all fetuses with irregular heartbeats do not need to be treated immediately and aggressively with a variety of medications.
"This confirms our earlier belief that irregular fetal heart beats do not warrant an aggressive approach from a risk-benefit standpoint," he said. "We do think it is still worth evaluating fetuses with irregular heart beats to find the one to two percent who may need medication before or after birth, but the study shows an irregular heart beat is nothing to get panicked about in most cases."
Other investigators on the study were Ren-Ing Liang, M.D, Semih Ozeren, M.D., both visiting research fellows; Kafui Demasio, M.D., a clinical fellow in the Department of Obstetrics and Gynecology; and Charles Kleinman, M.D., formerly of Yale and professor of cardiology pediatrics, obstetrics and gynecology, and diagnostic radiology.