Yarro Pilz replied: "You were prescribed the generic of Bactrim or Septra. Here's the label information: "Pregnancy Category C. In rats, oral doses of 533 mg/kg sulfamethoxazole or 200 mg/kg trimethoprim produced teratological effects manifested mainly as cleft palates. The highest dose which did not cause cleft palates in rats was 512 mg/kg sulfamethoxazole or 192 mg/kg trimethoprim when administered separately. In two studies in rats, no teratology was observed when 512 mg/kg of sulfamethoxazole was used in combination with 128 mg/kg of trimethoprim. In one study, however, cleft palates were observed in one litter out of 9 when 355 mg/kg of sulfamethoxazole was used in combination with 88 mg/kg of trimethoprim. In some rabbit studies, an overall increase in fetal loss (dead and resorbed and malformed conceptuses) was associated with doses of trimethoprim six times the human therapeutic dose. While there are no large, well-controlled studies on the use of trimethoprim and sulfamethoxazole in pregnant women, Brumfitt and Pursell, 5 in a retrospective study, reported the outcome of 186 pregnancies during which the mother received either placebo or oral trimethoprim and sulfamethoxazole. The incidence of congenital abnormalities was 4.5% (3 of 66) in those who received placebo and 3.3% (4 of 120) in those receiving trimethoprim and sulfamethoxazole. There were no abnormalities in the 10 children whose mothers received the drug during the first trimester. In a separate survey, Brumfitt and Pursell also found no congenital abnormalities in 35 children whose mothers had received oral trimethoprim and sulfamethoxazole at the time of conception or shortly thereafter. Because trimethoprim and sulfamethoxazole may interfere with folic acid metabolism, Bactrim IV Infusion should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus." Has the same doctor been caring for you your entire pregnancy? If so, he/she may have decided that the risk to you, due to kidney scarring, etc., outweighs the risk to the baby of the drug. Your kidneys are already working overtime, filtering your blood for both of you. And an untreated kidney infection can easily cause permanent damage. Call your doctor's office and explain your concerns. But don't be surprised if they recommend that you finish out the course of Bactrim. Cranberry juice and water are both good for UTIs, so you're taking care of yourself there. For what it's worth, both of my kids have a condition where the one-way valve between their kidneys and their bladders doesn't function as a one-way valve, which allows bacteria to build up and causes UTIs. They've been taking a small dose of Bactrim every day since their conditions were diagnosed. Which, in the case of my younger daughter, was when she was about a month old. I know that doesn't make you feel better about exposing your baby in utero, but your kidneys are really, really important."