Fetal weight estimation: comparison of two-dimensional US and MR imaging assessments.

Purpose: To prospectively define fetal density in the second half of pregnancy by using magnetic resonance (MR) imaging and to compare estimates of fetal weight based on ultrasonography (US) and MR imaging with actual birth weight.

Materials And Methods: Written informed consent was obtained for this ethics committee-approved study. In this cross-sectional study between March 2011 and May 2012, fetal density was calculated as actual birth weight at delivery divided by fetal body volume at MR imaging in 188 fetuses between 20 weeks and 2 days and 42 weeks and 1 day of gestational age.