Ultrasound measurement learning of fetal sex during the first trimester: does the experience matter?

Figures & data

Figure 1 Male sex: ultrasound identification of the male sex at the first trimester ultrasound scan shows tubercle’s angle >30°.

Figure 2 Female sex: ultrasound identification of the female fetal sex at first trimester ultrasound scan shows the genital tubercle parallel to the spinal column.

Note: Inset shows full ultrasound scan.

Figure 3 Success rate according to fetal sex algorithm.

Abbreviation: CRL, crown–rump length.

Figure 4 Global success rate according to CRL and divided by sex.

Abbreviation: CRL, crown–rump length.

Table 1 Results of univariate and multivariate analysis of independent variables and its relation to the success rate in the diagnosis of fetal sex

	OR	95% CI		P-value
Univariate		Lower	Higher
CRL (mm)	1.140	1.109	1.172	<0.001
Sonographer’s experience	1.064	0.766	1.479	0.711
Male fetus	2.744	1.862	4.044	<0.001
Multivariate
CRL (mm)	1.131	1.100	1.640	<0.001
Sonographer’s experience	0.948	0.871	1.031	0.213
Male fetus	2.197	1.469	3.286	<0.001

Abbreviations: CI, confidence interval; CRL, crown–rump length; OR, odds ratio.