Regardless of political or ideological views, detecting the embryonic heartbeat in the first trimester is a major milestone for a patient. Measured via ultrasound, normal beating of 90-110 bpm around 6 weeks’ gestation indicates a high probability of a successful pregnancy. Once the embryo becomes a fetus, around gestational weeks 8-9, a strong fetal heartbeat of 140-170 bpm should be detected. Finding a heartbeat is a reassuring sign. However, simply seeing and/or hearing the heart is not enough to ensure that the fetus will develop without problems.
Congenital heart defects (CHDs) are the most common birth defects worldwide and, although many CHDs can be mild forms, approximately 25% are severe forms requiring early detection and intervention.1 In addition, CHDs in the fetus can cause miscarriage, stillbirth, and infant deaths.
A 2014 analysis of data from the Wisconsin Stillbirth Service Program revealed that2 An analysis of the Active Malformations Surveillance Program at Brigham and Women’s Hospital also revealed CHDs as a major cause of stillbirths.3 In addition, a retrospective study of the Metropolitan Atlanta Congenital Defects program showed that, although 1-year survival of infants with severe CHDs has improved over the last 4 decades, mortality remains high.1
Because advances in medicine and surgical procedures have significantly reduced deaths attributable to CHDs, more women with a preexisting heart condition are becoming pregnant. Women who have a CHD, even if corrected, can experience pregnancy complications such as arrhythmias, thrombosis, and cardiac dysfunction. In addition, babies of women with CHDs have a higher risk of developing cardiac defects as well.
Therefore, it is critical that we closely monitor our patients – both the mother and her baby – to ensure that the fetal heart is present, functional, and developing normally. We have invited Dr. Shifa Turan, associate professor of obstetrics, gynecology, and reproductive sciences at the University of Maryland and director of the Fetal Heart Program at the University of Maryland Medical Center, both in Baltimore, to discuss the fetal heart. In this first section of a two-part series, Dr. Turan addresses how we can and should monitor fetal heart development.
Dr. Reece, who specializes in maternal-fetal medicine, is executive vice president for medical affairs at the University of Maryland, Baltimore, as well as the John Z. and Akiko K. Bowers Distinguished Professor and dean of the school of medicine. He is the medical editor of this column. He said he had no relevant financial disclosures. Contact him at