A systematic review looking at voiding function following various modes of vaginal deliveries using different analgesia showed a significantly higher risk of voiding dysfunction in women undergoing vaginal deliveries with epidural anaesthesia or instrumental deliveries. In one of the three studies conducted, the median time for bladder sensation to return in women having vaginal deliveries without epidurals, with epidurals, and after elective Caesarean sections under spinal anaesthesia were 122 minutes (95% IQR 112-136), 234 minutes (95% IQR 202-291) and 374 minutes (95% IQR 311- 425) respectively. The median volumes were 144 ml (95% IQR 112 -192), 200 ml (95% IQR 136- 336) and 152.2 ml (95% IQR 125 – 270) respectively. Examination of the accuracy of ultrasound bladder measurements showed a good correlation between the volume of urine present in the bladder and the volume of urine measured using the ultrasound scan. A double blind randomised controlled study assessed the effect of spinal and local anaesthesia on the bladder when used for incontinence surgery. The study showed that postoperatively patients having spinal anaesthesia had a first desire to void and a strong desire to void with smaller volumes of fluid in their bladder at 3 hours compared to 1 hour
