Radiographic pelvimetry--its use and possible radiation risk.

Radiographic pelvimetry is widely used in obstetrics. Every fourth primapara in Sweden is submitted to this radiographic examination. The frequency of the examination in the United States is estimated to a mean of 6% of all deliveries. The use of radiographic pelvimetry is now under intense debate and the missing argument in this discussion is a prospective study of an unselected group of parturients where progress and outcome of labour is referred to known pelvic dimension. Since the value of the method is questioned the frequent use of radiographic pelvimetry is justified only by an almost negligible radiation risk to the mother and her baby. Such a low risk is also an indispensable condition to allow the correct scientific evaluation of radiographic pelvimetry mentioned above. This paper presents the measurement results of absorbed radiation dose with the only radiographic pelvimetry method used in Sweden. The estimated radiation risk of the method, based on these figures, is 1 case of childhood malignancy in 50 000 pelvimetries. This corresponds to 4 years routine use of radiographic pelvimetry in Sweden. The annual incidence of childhood malignancy in Sweden is 220. The maternal risk is estimated to one tenth of the fetal risk.