Fetal foot length and its sonographic correlation with gestational age

Abstract

Introduction: Accurate assessment of gestational age and fetal growth using ultrasound is imperative in providing good quality antenatal and perinatal care. It provides a noninvasive reliable estimate of the gestational age and serves as a baseline upon which interval fetal growth can be assessed throughout pregnancy. Aim: The present study was undertaken to assess the relationship between gestational age and fetal foot length and to derive a nomogram correlating gestational age in weeks with fetal foot length. Materials and methods: This was a prospective, cross-sectional study conducted on 300 pregnant women between 18 and 39 weeks of gestation after obtaining their written informed consent. Our inclusion criteria were women with singleton pregnancies who were certain of their last menstrual periods; who had previous regular menstrual cycles; who had undergone a fi rst trimester dating scan; who had a normal anomaly scan; and with normal amniotic fl uid volume. Each patient underwent a detailed antenatal ultrasound study in which, in addition to routine fetal biometry, each fetal foot length was measured. In each fetus, the measurements of the two feet were averaged for analytical purpose. For each gestational age, the fetal foot length was calculated from the raw data and linear regression analysis was used to establish a relationship between sonographic gestational age and fetal foot length. The p value was also calculated to estimate the level of signifi cance. Results: Our study demonstrated a strong statistically signifi - cant linear relationship between gestational age and fetal foot length during the second and third trimesters of gestation.