title: Fetal sex assignment by first trimester ultrasound: a Tunisian experience.
abstract: OBJECTIVE
  To assess the feasibility and accuracy of fetal sex identification during the first trimester ultrasound exam.
  
  
  METHODS
  A prospective study was carried out on 312 fetuses at 11-14 weeks' gestation. The genital region was examined by transabdominal ultrasound. The angle of the genital tubercle to a horizontal line through the lumbosacral skin was measured. Fetal gender was assigned as male if this angle was > 30 degrees and female when it was < 10 degrees .
  
  
  RESULTS
  Sex assignment was feasible in 89.7% and accurate in 85.7% of fetuses. Accuracy was similar in males as in females (87.9% vs 83.3%; NS). However, accuracy increased significantly during the gestational age period in male (Chi-square for trend P = 0.03) but not in female (P = 0.41) fetuses. Compared with singletons, presence of multiple fetuses (n = 12) did not influence feasibility or accuracy (89.2% vs 96% and 85.6% vs 86.4% respectively). In male fetuses, there was a significant increase in the angle of the genital tubercle with increasing crown-rump length(CRL) (r = 0.667; p = 0.025), while in females the angle did not significantly change with increasing gestation.
  
  
  CONCLUSIONS
  Sonographic first trimester sex assignment is highly feasible and accurate.
authors.affiliation: Department A of Gynecology and Obstetrics, Tunisian Maternity and Neonatology Center, Rabta, 1007 Tunis, Tunisia.
authors.forename: Dalenda
authors.initials: D
authors.lastname: Chelli
authors.forename: Ahlem
authors.initials: A
authors.lastname: Methni
authors.forename: Kaouther
authors.initials: K
authors.lastname: Dimassi
authors.forename: Fethia
authors.initials: F
authors.lastname: Boudaya
authors.forename: Ezzedine
authors.initials: E
authors.lastname: Sfar
authors.forename: Béchir
authors.initials: B
authors.lastname: Zouaoui
authors.forename: Hela
authors.initials: H
authors.lastname: Chelli
authors.forename: Mohamed Badis
authors.initials: MB
authors.lastname: Chennoufi
mesh_terms: D001837:Body Weights and Measures / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D005333:Fetus / Q000033:anatomy & histology; D006801:Humans; D008297:Male; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012680:Sensitivity and Specificity; D012732:Sex Determination Analysis / Q000379:methods*; D014416:Tunisia; D016216:Ultrasonography, Prenatal / Q000379:methods*