Ultrasound measurement of tibia and fibula bone length in Thai fetus.

ABSTRACT

A prospective cross-sectional study was conducted in order to construct reference centile charts for tibia and fibula bone length of Thai fetuses. A total of 621 normal pregnant women, who attended the antenatal clinic at Siriraj Hospital, Mahidol University, Bangkok, were recruited between 12 and 41 weeks of gestation. We identified pregnant women who had regular menstrual period for at least 3 months without contraception prior to the current pregnancy; and whose uterine size at the time of examination was compatible with menstrual age. Each fetus was measured only once at a randomly assigned gestation age specifically for the purpose of this study. A total of 461 fetal tibia and fibula lengths were measured due to unfavorable fetal position in some cases. Regression models were fitted to estimate the mean and standard deviation for each parameter at each gestational age. The centile charts of both lower limb lengths for Thai fetuses were derived from regression equations and are presented.