title: [Evaluation of the embryonic and foetal heart rate at 6(+0) to 11(+6) weeks of gestation].
abstract: OBJECTIVE
  To establish the normal range of embryonic heart rate (EHR) and foetal heart rate (FHR) at 6(+0) to 11(+6) weeks of gestation, to evaluate the risk of pregnancy loss depending on EHR and FHR values and to establish if checking of FHR with the use of M-mode method is possible in different levels obstetric departments.
  
  
  METHODS
  Transvaginal or transabdominal ultrasound using M-mode in 255 singleton pregnancies. Maternal age varied between 16 and 44 years (mean 29 +/- 5 years). There were 67% primigravidas. Gestational week was established on the basis of CRL measurements. Demographic factors, obstetrical history and follow-up were collected. Data was statistically reviewed.
  
  
  RESULTS
  FHR varied between 47 and 192 bpm (mean 154 +/- 26 bpm). At 6 weeks, mean EHR was 116 +/- 21 bpm, then slowly increased, reaching mean 172 +/- 9 bpm at 10 weeks. At 11 weeks the mean FHR achieved the level of 165 +/- 7 bpm. The difference was statistically significant. The r-correlation ratio between FHR and the gestational week was 0.58. In case of 7 embryos (2.75%) at 6.1 to 8.1 weeks of gestation slow FHR was noted (< 100 bpm). The scan performed 7-10 days later revealed miscarriages in all cases.
  
  
  CONCLUSIONS
  EHR and FHR in the first trimester depends on gestational week. It increases since 6 to 9 weeks and decreases after 10 weeks. The highest values of FHR are observed between 9 and 10 weeks of gestation. The risk of early pregnancy loss increases significantly in case of detecting slow FHR. FHR can be checked by M-mode methods using any kind of ultrasound machine.
authors.affiliation: Il Katedra i Klinika Połoznictwa i Ginekologii AM w Warszawie.
authors.forename: Anita
authors.initials: A
authors.lastname: Hamela-Olkowska
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Wiech
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Jalinik
authors.forename: Dariusz
authors.initials: D
authors.lastname: Zaryjewski
authors.forename: Leszek
authors.initials: L
authors.lastname: Kornatowski
authors.forename: Joanna
authors.initials: J
authors.lastname: Dangel
mesh_terms: D000022:Abortion, Spontaneous / Q000517:prevention & control*; D000293:Adolescent; D000328:Adult; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging / Q000502:physiology*; D005865:Gestational Age; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D011044:Poland / Q000453:epidemiology; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000000981:diagnostic imaging*; D011261:Pregnancy Trimester, First; D011379:Prognosis; D012016:Reference Values; D016216:Ultrasonography, Prenatal / Q000379:methods*; D055815:Young Adult