The objectives of this study are to observe the clinical characteristics and incidence of diastasis of symphysis pubis during vaginal delivery and to evaluate the risk factors of the lesion.

16,000 vaginal delivery cases of our center from 1997 to 1999 were reviewed. The severe pain in symphysis pubis and walking difficulty after delivery were used as a diagnostic criterion. Several factors that increase the risk of this lesion during delivery were reviewed and analyzed by t-test between diastasis group (n=55) and normal group (n=100).

Fifty-five diastasis of symphysis pubis were diagnosed out of 16,000 normal vaginal delivery cases during that period. The widening of the joint ranged from 4mm to 34mm. Sixteen cases accompanied vertical mobility. No factor was proved to increase the risk of the lesion. Initial body weight of infant had suggestive significance (P=0.051).

We couldn't prove any risk factors that increased the risk of diastasis of symphysis pubis during vaginal delivery in this study. Further prospective studies with more cases would be needed to disclose the risk factors.