Sonographic nomogram of the fetal calf between 15 and 42 weeks' gestation using 3-dimensional sonography

Objective. The purpose of this study was to establish a new reference growth chart of calf muscle biometric measurements throughout gestation in normal singleton pregnancies. Methods. A prospective cohort study was designed. One hundred pregnant women were included in the study and assessed by 3-dimensional sonography. Excluded were those with multiple pregnancies, congenital anomalies, abnormal karyotypes, and polyhydramnios or oligohydramnios. Three-dimensional multiplanar sonographic images were used to measure the calf muscles: soleus, gastrocnemius, popliteal, peroneus longus, and tibialis posterior. Results. Calf muscle widths increased with increasing gestational age (R² = 0.857; P < .0001), and the ratio between calf muscles and the tibia increased as well (R² = 0.356; P = .001). Conclusions. The data provide a nomogram of calf width with a direct correlation between muscle growth and gestational age. This nomogram can offer a basis for normal calf development and may assist in distinguishing between different etiologies leading to clubfoot and other joint contractures associated with calf atrophy.