From a hasty review of the literature it would appear that serious interference with childbirth by vesical calculi is rather rare. Considering the enormous size which bladder stones sometimes attain, it is surprising that they are not a more common cause of dystocia. That they are not is doubtless due to their comparative rarity in women. Winkle found bladder stone in only one of 10,000 women examined.
Pinching of the bladder and anterior vaginal wall with resulting fistula, by stones too small to cause marked obstruction to the descending head, seems to be more common. Thus in Kotschurowa's case referred to by Hirst, labor lasted three days.
At the end of that time a gangrenous tumor protruded from the vulva, which tumor proved to be the bladder and anterior vaginal wall. The midwife in attendance perforated the tumor with her finger, whereupon a calculus 85 grains in weight was discharged.