What causes developmental dysplasia of the hip (DDH)?
Hip dysplasia is considered a “multifactorial trait.” Multifactorial inheritance means that many factors are involved in causing a birth defect. The factors are usually both genetic and environmental. Often, one gender (either male or female) is affected more frequently than the other in multifactorial traits. There appears to be a different “threshold of expression,” which means that one gender is more likely to show the problem than the other gender. For example, hip dysplasia is more common in females than males. One of the environmental influences thought to contribute to hip dysplasia is the baby’s response to the mother’s hormones during pregnancy. A tight uterus that prevents fetal movement or a breech delivery may also cause hip dysplasia. The left hip is involved more frequently than the right due to intrauterine positioning.
