Accuracy rate of sex determination in the first trimester ultrasonography

Objective: Our aim was to compare the fetal sex determined in the ultrasonographic examination carried out at weeks between 11 and 13 in singleton pregnancies with the sex determination at 22 weeks of gestation, and to calculate accuracy rates. Methods: Spontaneous singleton pregnant women who had first trimester screening between 2008 and 2010 and had no structural anomaly were evaluated. Fetuses on which sex determination was done between weeks 11 and 13, of which sex verification data were received in the ultrasonography carried out at 22 weeks of gestation, and which were evaluated by a single clinician were included to the study. A total of 395 fetuses complying with inclusion criteria were analyzed. The distribution of rates by years was reviewed. Results: Mean maternal age was found as 30.5±3.3 years, and mean week of gestation was 12.6±0.5. It was found in the verification ultrasonography made at 22 weeks of gestation that the accuracy of fetuses who were made sex determination between weeks 11 and 13 increased by years and reached a high rate as 89.9%. In previous years, the possibility to determine sex as female but to change the determination as male in the verification made at 22 weeks of gestation was found significantly (p<0.001) higher (about two times) than the possibility to determine sex as male but to change the determination as female in the verification made at 22 weeks of gestation, and this difference disappeared when determination percentage increased. Conclusion: The sex determination in ultrasonographic examinations between weeks 11 and 13 during pregnancy has an increasing accuracy rate as clinician’s experience increases.