CPD is best assessed by :

Methods of assesment of Pelvis Clinically Imaging studies Clinical Pelvimetry : Done manually Can be done beyond 37th week, better done after onset of labour Following are to be observed Sacrum Sacrosciatic notch Iscial spines Side walls Pubic arch Pubic angle Transverse diameter of outlet Imaging : X-ray pelvimetry,USG, CT ,MRI X-ray pelvimetry : Limited value in diagnosis Can only assess size and shape of pelvis Useful in cases with pelvic fractures Disadvantage : Radiation exposure to both mother and foetus (885 milirad) Erect lateral view CT Easier to perform Radiation exposure(45-425milirad) More accurate MRI More accurate to assess bony pelvis Assess pelvic capacity in different planes Assess foetal size and head volume, pelvic soft tissues No radiation risk Expensive,limited availability, more time taking USG : Accurately measures the biparietal diameter Reference: Mudaliar and Menon's clinical obstetrics,12th edition,Page no: 307