Pregnancy increases the risk of acquiring a UTI (urinary tract infection) and many women suffer from such infections even though they might not normally be prone to UTIs. Your story is not unusual. You can help to prevent such infections with a number of simple measures. Firstly, you should drink more water. If you need to urinate you should do so and not try to hold on. Always urinate after sexual intercourse. Also, when you have finished urinating you should wipe from front to back and not from back to front. The latter course of action could transfer coliform organisms from the anal area to the opening into the bladder. With regard to the second part of your question it is necessary to treat a UTI because failure to do so could result in acute inflammation of your kidneys, which could trigger labour and put the foetus in jeopardy. The antibiotics that we commonly use for treating UTI during pregnancy are not harmful to the foetus.