Pregnancy and post-pregnancy avascular necrosis of the femoral head.

Nine cases in the literature and seven patients in our series with hipache due to avascular necrosis of the femoral head have been reviewed. The onset of symptoms is related to pregnancy. The high adenocortical activity during pregnancy is invoked as a possible explanation of pregnancy avascular necrosis of the femoral head. Maternal parathyroid gland hyperplasia and the elevated parathyroid hormone during pregnancy may play an additional adverse effect on bones. Mechanical stress, due to a difficult labour or excessive weight gain during the last trimester of pregnancy, may be another aetiological factor.