title: First trimester bradycardia. A sign of impending fetal loss.
abstract: Normal first trimester fetal heart rates rise from an average of 100 beats per minute (bpm) at 5 to 6 weeks to 140 bpm at 8 to 9 weeks. The heart rates of 65 consecutive first trimester fetuses between 5+ and 8+ weeks were measured to determine whether unusually slow first trimester fetal heartbeats are associated with a poor outcome. All five pregnancies in which heart rates were below 85 ended in spontaneous miscarriage. This study suggests that first trimester bradycardia may be associated with a poor prognosis for the pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: L A
authors.initials: LA
authors.lastname: Laboda
authors.forename: J A
authors.initials: JA
authors.lastname: Estroff
authors.forename: B R
authors.initials: BR
authors.lastname: Benacerraf
mesh_terms: D000022:Abortion, Spontaneous; D001919:Bradycardia / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000503:physiopathology*; D006340:Heart Rate, Fetal; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis; D014463:Ultrasonography