title: Intrauterine ultrasonographic assessments of embryonic development.
abstract: OBJECTIVE
  Our purpose was to describe embryonal anatomic structures by use of intrauterine ultrasonography with a 20 MHz flexible catheter-based, high-resolution, real-time miniature transducer.
  
  
  METHODS
  Thirty-four women about to undergo therapeutic abortion from 7 to 9.9 weeks' gestation were studied with specially developed catheter-based, high-resolution, real-time miniature (2.4 mm outer diameter) ultrasonography transducer (20 MHz). A percentage of anatomic structures visualized at each gestational age is presented.
  
  
  RESULTS
  The number and the clarity of structures increased from 7 to 8 weeks of gestation; however, the image quality was degraded because of the increasing fetal size at 9 weeks. At 8 weeks secondary brain vesicles, spine, midgut herniation, liver, upper and lower limb buds, and sacral tail were visualized in all fetuses. The four-chamber view was first identified at 8 weeks, as were fingers or toes. The stomach was first noted at 9 weeks. The umbilical cord cyst was visualized in 8% of embryos at 7 weeks' gestation and in 29% of embryos at 8 weeks. One cystic hygroma was diagnosed at 8 weeks 5 days.
  
  
  CONCLUSIONS
  Intrauterine ultrasonography provides information on the visualization of anatomic structures of the embryo. In this limited series one embryonic malformation was demonstrated, and thus there is a potential for its use in the detection of malformations. These results suggest that intrauterine ultrasonography has the potential to be a supplement to transvaginal ultrasonography during the first trimester in high-risk pregnancies.
authors.affiliation: Department of Obstetrics and Gynecology, Shimane Medical University, Izumo 693, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Fujiwaki
authors.forename: T
authors.initials: T
authors.lastname: Hata
authors.forename: K
authors.initials: K
authors.lastname: Hata
authors.forename: M
authors.initials: M
authors.lastname: Kitao
mesh_terms: D001921:Brain / Q000196:embryology; D005314:Embryonic and Fetal Development; D005260:Female; D005865:Gestational Age; D006321:Heart / Q000196:embryology; D006801:Humans; D018878:Limb Buds / Q000000981:diagnostic imaging / Q000196:embryology; D008099:Liver / Q000000981:diagnostic imaging / Q000196:embryology; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D016216:Ultrasonography, Prenatal