title: [Effects of B-ultrasonic radiation during pregnancy on reproductive outcome].
abstract: OBJECTIVE
  To study the effects of B-ultrasonic scanning during pregnancy on reproductive outcome, including pregnant outcome and neonatal status.
  
  
  METHODS
  Data of reproductive outcome and B-ultrasonic examination were extracted from the questionnaires and obstetric records of 12,224 primigravidas in eight hospitals of Beijing during May 1992 to April 1993. Their reproductive outcomes were analyzed according to frequency and gestational weeks they had B-ultrasonic examination taken, adjusted for potential confounding factors, such as age at pregnancy, smoking and drinking during pregnant period and history of spontaneous abortion, by logistic regression.
  
  
  RESULTS
  There was no statistically significant difference in reproductive outcomes between groups, who had B-ultrasonic examination taken for two, three and four times or more and who had only once, respectively, who had more than four times and who had less than three times, and who had their first examination before and after the eighth week of gestation, or before and after the 12th week of gestation.
  
  
  CONCLUSIONS
  No adverse reproductive outcome due to exposure to diagnostic dose of B-ultrasound radiation during pregnancy has been found.
authors.affiliation: Department of Maternal and Child Health, Beijing Medical University, Beijing 100083, China.
authors.forename: S
authors.initials: S
authors.lastname: Fu
authors.forename: Y
authors.initials: Y
authors.lastname: Bao
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: Y
authors.initials: Y
authors.lastname: Hu
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: F
authors.initials: F
authors.lastname: Zhang
mesh_terms: D000022:Abortion, Spontaneous; D000328:Adult; D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D016216:Ultrasonography, Prenatal / Q000009:adverse effects*