Evaluation of fetal spine biometry between 11 and 14 weeks of gestation

This study was designed to establish a fetal spine nomogram for age 11 through 14 weeks of gestation and to document relations among fetal spine length, distance and angle. These parameters were prospectively measured during the first trimester of singleton pregnancies, along with nuchal translucency, over a 3-year period. A total of 430 fetuses were included in the study. The regression equations among fetal spine parameters and gestational age were as follows: Spine length (mm) = 1.116 x gestational age (days) - 59.169; spine distance (mm) = 1.079 x gestational age (days) - 59.038; head-spine angle = 0.740 x gestational age (days) + 4.735; spine length:spine distance ratio = -0.002 x gestational age (days) + 1.234. Prenatal age-specific reference intervals for fetal spine biometry between 11 and 14 weeks of gestation may assist in evaluation of fetuses investigated for genetic abnormalities that can be expressed by deviation in spine length, distance, or angle.