title: Outcome of early first-trimester pregnancies (< 6.1 weeks) with slow embryonic heart rate.
abstract: OBJECTIVE
  The purpose of this article is to assess prospectively the value of concordant versus discordant gestational age (GA) calculations in predicting subsequent embryonic demise in embryos with a slow heart rate, as determined on early first-trimester ultrasound.
  
  
  METHODS
  Thirty-six consecutive singleton pregnancies with slow embryonic heart rate (< 100 beats/min) measured on a 5.0- to 6.1-week ultrasound were prospectively identified. Pregnancies were defined as "discordant" if there was more than 5 days' difference between GA determined by biometrics compared with GA determined by last menstrual period and were defined as "concordant" if there was less than 5 days' difference between the GA measurements.
  
  
  RESULTS
  Of the 36 embryos with heart rate less than 100 beats/min at 5.0-6.1 weeks' GA, 16 went on to demise and 20 survived. Of the 16 that went on to demise, 14 were discordant (88%) and two were concordant (12%). Of the 20 that survived, 16 were concordant (80%) and four were discordant (20%). The proportion of discordant pregnancies that went on to demise was 14 of 18 (negative predictive value, 78%). The proportion of concordant pregnancies that went on to survival was 16 of 18 (positive predictive value, 89%). The rate of demise in the discordant group was significantly higher than that in the concordant group (p < 0.001, Fisher's exact test).
  
  
  CONCLUSIONS
  Embryonic heart rate less than 100 beats/min detected at 6.1 weeks or less is not necessarily a poor prognostic indicator. The likelihood of subsequent first-trimester survival is significantly higher if there is concordance between GA as calculated by biometrics and last menstrual period than if there is discordance.
authors.affiliation: Weill Cornell Imaging, New York Presbyterian Hospital, NY 10065, USA. ekarleo@gmail.com
authors.forename: Elizabeth Kagan
authors.initials: EK
authors.lastname: Arleo
authors.forename: Robert N
authors.initials: RN
authors.lastname: Troiano
mesh_terms: D015148:Cardiotocography; D005260:Female; D005865:Gestational Age; D006340:Heart Rate, Fetal; D006801:Humans; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal