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Pelvic bone surgery and natural delivery: absolute and relative contraindications

Objective. The gynecologist often involves the orthopaedic surgeon in the evaluation of pregnant women with previous medical history of pelvic surgery who will give birth. Young women can receive pelvic surgery for proximal femoral fractures, sacro-iliac or pelvic ring fractures, avascular necrosis of the femoral head, hip dysplasia and severe ankylosing spondylitis. The aim of this study is to determine whether such women can accomplish a natural delivery or should have caesarean delivery (C-section). 
Methods. Pubmed and the Cochrane Database of Reviews were searched for manuscripts including the years 1970 to present. 
Results. It is important to discriminate between pathological and/or post-surgical conditions affecting the coxo-femoral joint which constitute an absolute contraindication to vaginal delivery from other circumstances that may have a relative contraindication. Orthopaedic relative indications for C-section may include coxo-femoral pathologies where coxo-femoral joint range of motion is limited and women cannot assume a given position that is deemed necessary by the obstetric specialist for natural delivery. Conditions requiring C-section are those producing an insufficient width of the bony birth canal; when the transverse mid-pelvis diameter is <9.5 cm, then the probability of C-section is increased. 
Conclusions. It is not mandatory to perform a C-section in all women with a past medical history of pelvic surgery; accurate medical history collection, imaging technologies and ultrasound make it possible decide if a C-section is compulsory.