Effect of increase in birth weight in a newborn on hip ultrasonography.

Exposure to the pressure experienced by higher birth weight babies during the intrauterine period might cause hip dysplasia. The aim of this study is to determine the effect of birth weight in newborns on hip ultrasonography when the paternal and maternal risk factors are excluded. A total of 701 babies born at 38-42 gestational weeks were included in the study. Hip ultrasonography was performed within 7 days following birth using the Graf technique in the babies without risk factors for developmental dysplasia of the hip. Images obtained were controlled with respect to conformity to the Graf method and angular measurements were performed. According to the α and β angle values obtained, type 1A and 1B hips were categorized as mature; type 2A hips were categorized as immature; and type 2C, D, 3A, 3B, and 4 hips were categorized as pathological hips. The results obtained were analyzed for the effect of birth weight on the angular values and hip typing. The birth weight of the babies was 338,488 ± 48,241 g (2030-6124 g). It was determined that the birth weight had no effect on the values of α and β angles in the male babies (P=0.21, 0.76). It was determined that increasing birth weight decreased the α angle value (P=0.001) and caused no difference in the β angle value (P=0.057) in the female babies. It was found that birth weight had no effect on hip typing in both female and male babies (P=0.060, 0.22). Increases in birth weights caused decreases in ultrasonographic α angles only in female babies.