Early fetal sex determination by Ultrasound Presented by R3 邱邱邱 Supervisor VS 邱邱邱 91.3.13 Introduction • Fetal gender assignment during ultrasound evaluation: parent’s curiosity, identification of normal gender development, heritable sex –linked disease • Especially X- linked disorder: Hemophilia, Duchenne’s muscular dystrophy Introduction • Britt-Marie, Acta Obstet Gyne Scand, 1981: - Fetal sex determination in the 17th, 32nd and the 38th week of gestation: easiest in the 32nd week ( 74 % ) • With the improvement of the ultrasound improvement, earlier fetal sex identification became possible Introduction • Second trimester sex determination: Male: scrotum and penis were seen Female: labia majora were visualized • Reece et al Am J Obstet Gynecol: - Can ultrasonography replace amniocentesis in fetal gender determination during the early second trimester? ( overall prediction rate: 92.7% ) Introduction • “ The Sagittal Sign”: Donald S Emerson, J Ultrasound Med, 1989: - An early second trimester sonographic indicator of fetal gender ( fig ) - Cranial notch vs caudal notch - From 14 to 20weeks, sagittal sign yields a gender prediction in 82% of fetuses ( 86% of males, 79% of females ) Introduction • Fig Late embryonic development of external genitalia • Toward the middle of the 2nd trimester, when the notches are not as clearly visualized, the sign loses significance: Clitoris and vestibule: become relatively small compared to trunk size Penis: fails to maintain consistent cranial angulation Material and method • • • • • • • • Seventy-five pregnant women on whom routine ultrasound screening was done in our obstetric clinic were enrolled in our study during December, 2001 All had gestational ages between 11 and 16 weeks, singleton ( on the basis of ultrasound findings) Ultrasound unit: ALOKA Prosound 5000 All by transabdominal route Within 15 minutes Midsagittal or transverse view Confirmatory as ultrasound examination follow up by reviewing of charts or telephone interview Prospective investigation Material and methods • Midsagittal plane: assigned as male if the angle of the genital tubercle to a horizontal line through the lumbosacral skin surface was greater than 30 degree and female when the genital tubercle was parallel or convergent ( less than 30 degree ) to the horizontal line No extension of limbs and spine Material and Methods • Transverse plane: Male genitalia were identified when a uniform, dome-shapes structure was seen at the base of the fetal penis Female genitalia were identified by visualizing two or four parallel lines • Most of the cases were not aware of sex identification during ultrasound examination Discussion • Genital tuberclePhallusPenis or Clitoris 11 week 12 week • B Benoit doubt??? Whitlow and Elfrat: gender identification between 11 and 14 weeks ( 78% accuracy for Whitlow and 70.3% accuracy for Elfrat at 11 weeks ) Transverse planes should be used after 14 weeks only 13+ weeks, female Conclusion • Although the accuracy of early sex determination by the ultrasound was not low, it would never have definite confirmation in such an early stage at present Thanks for your attention [...]... Discussion • Factors associated with nonvisualization: maternal obesity, fetal axis, fetal movement, skill and experience Discussion • D.A,L.Pedreira, Ultrasound in Obstetrics and Gynecology,: “ Fetal phallus ‘erection’ interfering with the sonographic determination of fetal gender in the first trimester” - more common in the early first trimester, suggest a progressive maturation of the mechanism... It may happen in both sexes Discussion • Genital tuberclePhallusPenis or Clitoris 11 week 12 week • B Benoit doubt??? Whitlow and Elfrat: gender identification between 11 and 14 weeks ( 78% accuracy for Whitlow and 70.3% accuracy for Elfrat at 11 weeks ) Transverse planes should be used after 14 weeks only 13+ weeks, female Conclusion • Although the accuracy of early sex determination by the ultrasound...Results • Totally seventy-five cases Thirteen cases were lost of follow up and still had two cases having no sex identification yet • Sixty cases were enrolled in this study finally Table 1.Gender determination in 60 fetuses between 11 and 16 weeks of gestatuon wuth the use of ultrasonography 邱 邱 邱 Confirmed 邱 Male Ultrasound 邱 邱 邱 邱 Female Total No %... should be used after 14 weeks only 13+ weeks, female Conclusion • Although the accuracy of early sex determination by the ultrasound was not low, it would never have definite confirmation in such an early stage at present Thanks for your attention