In this study, the fetal nonmuscular soft tissue is evaluated prenatally in 52 uncomplicated singleton pregnancies at 36 weeks of gestation or later. The means and standard deviations of the NMST at the midarm region and the ratio of NMST to HL are 6.0 +/- 1.0 mm and 0.08 +/- 0.02, respectively. No correlation was seen between the NMST and birth weight.