Safe Antibiotics for UTI in Pregnant Women at 17 Weeks
Nitrofurantoin is the preferred first-line antibiotic for treating UTIs in pregnant women at 17 weeks gestation, followed by fosfomycin and cephalexin as alternatives. 1
First-Line Options
Nitrofurantoin
- Dosage: 100 mg twice daily for 5 days 1
- Safety profile: Safe during second trimester (17 weeks) 1, 2
- Efficacy: High bacteriological cure rates for uncomplicated UTIs 1
- Contraindications: Should be avoided near term (>36 weeks) due to risk of hemolytic anemia in the newborn 2
Fosfomycin
- Dosage: Single 3g dose 1, 3
- Advantages: Convenient single-dose treatment with high compliance 3
- Safety: Safe during pregnancy with minimal systemic absorption 2
Alternative Options
Cephalexin (First-generation cephalosporin)
- Dosage: 500 mg twice daily for 3-7 days 1
- Safety: Well-established safety profile in pregnancy 4
- Considerations: Good option if resistance to first-line agents is suspected 1
Treatment Considerations
Importance of Treatment
- Untreated UTIs in pregnancy can progress to pyelonephritis in 20-40% of cases 1
- Pyelonephritis increases risk of preterm delivery and low birth weight 2
- Treatment of bacteriuria during pregnancy reduces risk of pyelonephritis from 20-35% to 1-4% 1
Antibiotics to Avoid
- Trimethoprim: Contraindicated in first trimester due to folate antagonism 1
- Trimethoprim-sulfamethoxazole: Avoid in last trimester due to risk of kernicterus 1
- Fluoroquinolones: Not recommended during pregnancy due to potential effects on fetal cartilage development 1
- Tetracyclines: Contraindicated due to effects on fetal bone development and teeth discoloration 1
Follow-up Recommendations
- Obtain urine culture before starting treatment to confirm diagnosis 1
- Follow-up urine culture 1-2 weeks after completing therapy to confirm cure 1
- No need for routine post-treatment urinalysis if symptoms resolve 1
Special Considerations
- For recurrent UTIs in pregnancy, prophylactic antibiotics may be considered after the initial infection is treated 5
- For suspected pyelonephritis, hospitalization and IV antibiotics are recommended (ceftriaxone or cefotaxime) 2
Pitfalls to Avoid
- Failure to obtain urine culture: Always confirm diagnosis with culture before treatment 1
- Inadequate follow-up: Ensure complete resolution with follow-up culture 1
- Inappropriate antibiotic selection: Avoid antibiotics contraindicated in specific trimesters 1
- Inadequate treatment duration: Short courses may lead to treatment failure and progression to pyelonephritis 1
- Missing asymptomatic bacteriuria: Screen all pregnant women at least once in early pregnancy 1
Remember that treating UTIs in pregnancy is essential to prevent complications that could affect both maternal and fetal outcomes. The choice of antibiotic should balance efficacy against the causative organism with safety for the developing fetus.