Prospective study of diagnostic value in fetal limb abnormalities in 11~13+6 weeks of gestation on prenatal ultrasonography

Abstract

Objective To explore the diagnostic value in fetal limb abnormalities in 11 to 13+6 weeks of gestation on prenatal ultrasonography. Methods A total of 33 981 fetuses of 33 824 pregnant women including 157 twin pregnancy underwent nuchal translucency thickness (NT) ultrasound examination in our hospital from September 2012 to June 2016 prospectively. Meanwhile, the fetal limbs were meticulously screened using a systematic continuous sequence approach. We recorded the maternal age, gestational weeks, crown rump length (CRL), nuchal translucency thickness (NT), types of limb abnormalities and other abnormalities. Up to induced labor or birth, all fetuses were followed up and compared with the findings of ultrasound. Results Fetal limb deformities were found in 101 cases in 23 160 fetuses who were followed-up by the prenatal ultrasonography in 11 to 13+6 weeks of gestation to the induced labor or birth. Among deformed 101 cases in 172 deformed limbs, 82 fetuses (82/23 160) were observed by ultrasound in 153 deformed limbs. The rate of fetal limb deformity was 0.44% (101/23 160) and rate of accuracy on ultrasound was 81.2% (82/101). The underdiagnosed 19 fetuses on ultrasound (18.8%, 19/101) had palms or feet deformities in 21 sites, including 10 talipes equinovarus, 5 polydactylism, 1 ectodactyle, 2 digital dysplasia, and 1 syndactylism. The sensitivity, specificity, positive predictive value, and negative predictive value of ultrasound in diagnosis of fetal limb deformities in 11 to 13+6 weeks were 81.2% (82/101), 100.0% (82/82), 100.0% (82/82), 99.9% (23 059/23 078). Conclusion Prenatal ultrasonography in systematic continuous sequence approach is helpful and effective for fetal limb abnormalities in 11-13+6 weeks of gestation. Because underdiagnosis is unavoidable in fetuses with deformities in feet and palms on ultrasonography, orderly and normalized screening is important. Key words: Fetal diseases; Congenital abnormalities; Limb deformities; Ultrasonography; Gestational age