Estimation of fetal shoulder width by measurement of the humerospinous distance by ultrasound.

Abstract

The present study was undertaken to find a practical method for estimating the fetal shoulder width by ultrasound. Sixty pregnant women at term were included in the study. The distance between the lateral margin of the fetal cartilaginous caput humeri and the processus spinosus of the cervical vertebra C7 (humerospinous distance) was measured by ultrasound. The neonatal shoulder width was measured with a craniometer during the first postnatal day. Linear regression analysis was used to calculate the correlation between the humerospinous distance and the shoulder width, and a significant linear correlation (r = 0.612, p < 0.001) was shown. Although, in this small study, we could not show a relationship between humerospinous distance and dystocia, we feel a clinical study of humerospinous distance as a predictor of shoulder dystocia is indicated.