Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2012, 156(4):324-329 | DOI: 10.5507/bp.2012.022

Ultrasound evaluation of fetal gender at 12-14 weeks

Marek Lubusky^a,b, Martina Studnickova^a, Ales Skrivanek^a, Katherine Vomackova^c, Martin Prochazka^a

^a Department of Obstetrics and Gynecology, University Hospital Olomouc, Czech Republic

^b Department of Medical Genetics and Fetal Medicine, University Hospital Olomouc

^c Department of Surgery I, University Hospital Olomouc

Aims: The aim of this study was to assess the feasibility and accuracy of fetal gender assignment by transabdominal ultrasound at 12-14 weeks of gestation.

Methods: Fetal gender assessment was performed in 1222 singleton pregnancies. In all fetuses the crown-rump length (CRL) was measured and the genital area of the fetus was examined in the mid-sagittal plane. The result of ultrasound examination was compared to the phenotypic sex of the newborn after delivery.

Results: The feasibility as well as accuracy in determining gender increased with growing fetal CRL. At CRL < 50 mm (gestational age < 11+4) the feasibility was 39.1% and accuracy 30.5% (40.9% in male gender vs 24.3% in female gender). At CRL 50-54.9 mm (gestational age 11+4 to 12+0) the feasibility was 63.5% and accuracy 75.0% (89.1% in male gender vs 66.7% in female gender). At CRL 55-59.9 mm (gestational age 12+0 to 12+2) the feasibility was 90.5% and accuracy 96.6% (99.1% in male gender vs 93.5% in female gender). At CRL ≥ 60 mm (gestational age ≥ 12+2) the feasibility was 97.4% and accuracy 100.0% (100.0% in male gender vs 100.0% in female gender).

Conclusions: Fetal gender may reliably be determined when CRL ≥ 60 mm (gestational age ≥ 12+2). Male gender may already be reliably determined when CRL ≥ 55 mm (gestational age ≥ 12+0). If CRL < 50 mm (gestational age < 11+4) the gender cannot be reliably predicted.

Keywords: fetal gender, fetal sex, first trimester, ultrasonography

Received: August 27, 2011; Accepted: February 14, 2012; Prepublished online: April 19, 2012; Published: December 12, 2012  Show citation