title: Transvaginal assessment of fetal anatomy at 11 to 16 weeks of gestation in relation to fetal position.
abstract: OBJECTIVE
  To investigate the ability of the high-frequency transvaginal scanning technique to assess embryo-fetal anatomy in early pregnancy in relation to fetal position and in comparison with transabdominal scan.
  
  
  METHODS
  A study population of 1,402 pregnant women were examined by transvaginal ultrasonography performed at 10(+1) to 16(+0) weeks of pregnancy. At 14(+1) to 16(+0) weeks of gestation, an ultrasonographic examination was performed in 247 pregnant women by transvaginal and transabdominal route. The criteria necessary for an adequate visualization of fetal organs and structures were met.
  
  
  RESULTS
  The visualization rate of complete fetal anatomy increased with increase in menstrual age and fetal position affected this possibility. A detailed brain anatomy was more easily viewed with the fetus in the cephalic or transverse position than in the breech position, whereas the thoracic and abdominal anatomy were viewed more easily with the transverse position compared to the cephalic or breech position. Complete surveys of fetal anatomy were possible in 50% and 62% of women with transabdominal scan and in 85% and 85% with transvaginal one at 15 and 16 weeks' gestation, respectively (p < 0.001).
  
  
  CONCLUSIONS
  A detailed assessment of fetal structures was possible in most cases at 13 weeks of gestation. Fetal position can influence this capability. At 14(+1) to 15(+0) weeks' gestation more anatomical surveys were completed with a transvaginal scan compared to a transabdominal one and this was influenced by fetal position.
authors.affiliation: Department of Obstetrics and Gynecology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Rosati
authors.forename: L
authors.initials: L
authors.lastname: Guariglia
authors.forename: A
authors.initials: A
authors.lastname: Bertuzzi
mesh_terms: D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D007746:Labor Presentation; D011247:Pregnancy; D016216:Ultrasonography, Prenatal; D014621:Vagina