As someone said water water and more water. I have had more than my fair share of UTI's and they are horrible. You are lucky if it was picked up in urine sample and you have no symptoms. I would look into whether or not "Ural" or something similar is safe to take when pregnant. I found this when i googled but it doesnt say anything about been pregnant (sorry mods if i am not allowed to post this. Please remove if not appropriate)

"Ural is a pleasantly flavoured effervescent drink which provides relief from painful burning symptoms of urinary Tract Infections. Ural helps to neutralize the acid in the urinary tract while assisting in eliminating organisms that cause infection.
Directions
Adult Dose: Dissolve contents of 1-2 sachets in a glass of cold water. May be taken 4 times daily for 5 days or as directed by the physician.
Ingredients
Each sachet contains:
sodium bicarbonate 1.76g
tartaric acid 890mg
citric acid anhydrous 720mg
sodium citrate anhydrous 630mg.
Also contains saccharin.
This preperation contains 644mg of sodium per sachet which should be taken into account by those on a low sodium diet.
Warnings
If symptoms persist for more than 2 days of using ural, please see your health care professional."