[Hip algodystrophy and pregnancy]. 
We report two cases of algodystrophy of the hip in pregnancy.  The principle characteristics of the condition are: the occurrence of the symptoms in the second or third trimester of the pregnancy; and these are more marked on the left than on the right hip and radiological decalcification.  MRI is accurate, specific and non invasive and it has largely taken the place of scintigraphy and tomodensitometry in making the diagnosis and in the differential diagnosis of early aseptic necrosis of the femoral head.  Recovery always occurs in less than a year without sequelae.  The physiopathogenic mechanism still is to be discussed but it does seem that the mechanical factors play a very important role.