First trimester fetal cardiac activity. Sonographic documentation of a progressive early rise in heart rate.
Journal Article (Journal Article)
The heart rates of 124 first trimester fetuses were determined with real-time sonography and were analyzed with regard to gestational age. The mean embryonic heart rate increased from 101 beats per minute (bpm) at 5 to 5.95 menstrual weeks to 143 bpm at 8 to 8.95 weeks. After nine weeks, the rate reached a plateau, ranging from 137 to 144 bpm. Slower heart rates are normal early in the first trimester and should not be misinterpreted as an abnormal finding or mistaken for maternal pulsations.
- Hertzberg, BS; Mahony, BS; Bowie, JD
- October 1988
Volume / Issue
- 7 / 10
Start / End Page
- 573 - 575
International Standard Serial Number (ISSN)
Digital Object Identifier (DOI)