title: First trimester volumetric measurements: relation with hormone levels and fetal heart rate.
abstract: OBJECTIVE
  This study aimed to examine two-dimensional ultrasound (2D US) volumetric measurements of 1st trimester structures and their relationship with β-hCG, progesterone, and fetal heart rate (FHR) in 6-10 weeks healthy pregnant women.
  
  
  METHODS
  Using conventional 2D transvaginal ultrasound imaging, the crown rump length (CRL), yolk sac (YS) and gestational sac (GS) were measured in 80 women. Volumetric measurements were done in 32 cases that were selected among 80 women, using a simplified formula for the volume of a prolate ellipsoid: V = 0.523 × length × height × width. The β-hCG and progesterone levels were recorded. The heart rate was determined from M-mode tracings using electronic calipers.
  
  
  RESULTS
  Moderately positive correlation was found between FHR versus CRL, embryo volume and GS volume. FHR increased linearly with CRL value, till CRL became 15 mm, after which it formed a plateau. β-hCG increased linearly till CRL was 15 mm, and then it formed a plateau. Progesterone level was stable till CRL became 20 mm, embryo volume 2 cm(3), after which it increased linearly.
  
  
  CONCLUSIONS
  Various ranges of relations are observed between FHR, obstetric, and hormonal measurements. The relationship between these parameters might be used for determination of abnormal growth and adverse outcomes in early pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Fatih University, Ostim Mah. 1290. sok, Nevbahar Konutları A7 Blok, No: 43, Yenimahalle, Ankara, Turkey. nerminkosus@gmail.com
authors.forename: Nermin
authors.initials: N
authors.lastname: Köşüş
authors.forename: Aydın
authors.initials: A
authors.lastname: Köşüş
authors.forename: Nilgün Oztürk
authors.initials: NO
authors.lastname: Turhan
mesh_terms: D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D018568:Crown-Rump Length; D005260:Female; D047109:Fetal Development / Q000502:physiology; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011374:Progesterone / Q000097:blood*; D016216:Ultrasonography, Prenatal; D055815:Young Adult
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D011374:Progesterone