Effectiveness of prenatal ultrasound in fetal sex identification: a systematic review and meta-analysis

Abstract

This systematic review and meta-analysis aimed to assess the accuracy and success rate of ultrasound in determining fetal sex. A search was conducted on Medline, Cochrane Library, and EMBASE databases, and the reference lists of selected studies were also reviewed. Meta-analyses were performed using Revman 5.4.1 and Meta-DiSc 2.0. Twenty-eight studies met the criteria for inclusion in the systematic review. Nine studies reported the accuracy rate of first-trimester fetal sex identification, with a mean accuracy of 85% and a median of 87%. Six studies provided accuracy rates for second and third-trimester identifications, with mean and median rates of 92% and 99%, respectively. A pooled sensitivity and specificity analysis shows that the sensitivity increased from 69% at 11 weeks to 89% at 12 weeks to 96% at 13 weeks. Forest plots on the success rates indicated no significant statistical differences between first-trimester ultrasound sex determination and actual birth sex, with p values of 0.06 for males and 0.08 for females. Similarly, second and third-trimester forest plots showed p values of 0.70 for males and 0.14 for females. In conclusion, ultrasound accuracy for fetal sex determination rises from 87% in first to 99% in second trimesters. The success rate shows no significant difference for either trimester. However, male sex is more easily detected in the second and third trimesters, while female sex is more easily detected in the first trimester. The sensitivity of fetal sex detection in the first trimester increases with gestational age. These findings suggest that prenatal ultrasound sex determination can be useful in managing sex-related pregnancy complications.

Keywords: Angle of genital tubercle; Anogenital distance; Determination; Fetal sex; Sagittal sign; Ultrasound.