Why do I keep needing to use the toilet?

Throughout the whole pregnancy, the womb presses the front on the bladder, which causes increased urge to pee. Some patients have the womb pressing on the exit of the bladder, which causes retention of urine. If it presses onto the back (where the rectum is), it can cause constipation. As the faeces liquifies, it might result in diarrhoea when the mother is finally able to pass it out.