The old FDA pregnancy letter categories (A, B, C, D, X) were officially phased out in 2015 and replaced by the Pregnancy and Lactation Labeling Rule (PLLR), but many clinicians still reference the historical categories because they remain familiar for exams and clinical memory.

Here are the historical categories plus the current practical guidance:

Drug

Old FDA Pregnancy Category

Current Practical Guidance

Nitrofurantoin

B

Generally considered safe in pregnancy except near term; avoid during labor/delivery if possible

Trimethoprim-sulfamethoxazole (Bactrim)

D near term; previously C overall depending on trimester

Avoid especially 1st trimester and near delivery if alternatives available

Ciprofloxacin / fluoroquinolones

C

Generally avoided in pregnancy unless benefits outweigh risks

Nitrofurantoin

Nitrofurantoin

Historical category

• Category B

Main pregnancy concerns

Usually considered safe for:

• cystitis
• asymptomatic bacteriuria

Avoid near term (38–42 weeks), during labor, or in neonates because of:

• theoretical risk of hemolytic anemia
• especially in G6PD deficiency

Current OB guidance

ACOG guidance on UTIs in pregnancy

• Reasonable first-line option in 2nd and 3rd trimesters
• May still be used in 1st trimester if better alternatives unavailable

TMP-SMX (Bactrim)

Trimethoprim-sulfamethoxazole

Historical category

• Trimethoprim: Category C
• Sulfonamides near term: often treated functionally as Category D risk

Main pregnancy concerns

First trimester

Trimethoprim is a folate antagonist:

• concern for neural tube defects
• congenital malformations

Near term

Sulfonamides may:

• displace bilirubin
• increase theoretical risk of kernicterus in newborns

Current practical recommendation

• Avoid in first trimester if alternatives exist
• Avoid near delivery if possible
• Sometimes still used when culture-directed and necessary

Fluoroquinolones

Examples:

• Ciprofloxacin
• Levofloxacin

Historical category

• Category C

Main pregnancy concerns

Animal studies suggested:

• cartilage toxicity
• arthropathy in developing fetus

Human data are less alarming than originally feared, but guidelines still generally avoid routine use in pregnancy.

Current recommendation

Avoid unless:

• resistant organism
• severe allergy to safer agents
• maternal benefit outweighs fetal risk

High-Yield Clinical Summary

Drug

1st Trimester

2nd/3rd Trimester

Near Delivery

Nitrofurantoin

Usually acceptable if needed

Commonly used

Avoid if possible

TMP-SMX

Avoid if possible

Sometimes acceptable

Avoid

Fluoroquinolones

Avoid

Avoid

Avoid

Common Board-Style Pearl

For pregnant women with uncomplicated cystitis:

• cephalexin is commonly safest/default
• nitrofurantoin frequently used after 1st trimester
• avoid fluoroquinolones routinely
• avoid TMP-SMX early and late pregnancy if alternatives exist

Current treatment guidelines for urinary tract infections (UTIs) in women depend on whether the infection is:

• Uncomplicated cystitis (simple bladder infection)
• Pyelonephritis (kidney infection)
• Complicated UTI
• Pregnancy-associated UTI
• Recurrent UTI

The main current guidance comes from the Infectious Diseases Society of America, American Urological Association, and European Association of Urology. The newest major IDSA update for complicated UTIs was released in 2025.  

1. Acute Uncomplicated Cystitis (Most Common)

Healthy nonpregnant women with dysuria/frequency and no fever or flank pain.

First-line antibiotics

Nitrofurantoin (preferred)

• Nitrofurantoin monohydrate/macrocrystals:
  • 100 mg PO BID x 5 days
• Avoid if:
  • suspected pyelonephritis
  • severe renal impairment
  • systemic symptoms

TMP-SMX (Bactrim DS)

• 160/800 mg PO BID x 3 days
• Use only if:
  • local E. coli resistance <20%
  • no sulfa allergy
  • no recent TMP-SMX exposure

Fosfomycin

• 3 g PO once
• Useful for resistant organisms/ESBL risk

Pivmecillinam

• Newly FDA approved in US (2024)
• First-line option for uncomplicated cystitis

2. Antibiotics No Longer Preferred First-Line

Fluoroquinolones

Examples:

• ciprofloxacin
• levofloxacin

These work well but are generally reserved because of:

• tendon rupture risk
• neuropathy
• aortic complications
• resistance promotion

Still used for:

• pyelonephritis
• complicated UTI
• resistant organisms

Beta-lactams

Examples:

• amoxicillin-clavulanate
• cefpodoxime
• cephalexin

Usually second-line because efficacy is somewhat lower.

3. When To Suspect Pyelonephritis (Kidney Infection)

Symptoms:

• fever
• flank pain
• nausea/vomiting
• CVA tenderness
• systemic illness

Treatment

Outpatient:

• ciprofloxacin
• levofloxacin
• TMP-SMX if susceptible

Inpatient/severe:

• ceftriaxone
• cefepime
• piperacillin-tazobactam
• carbapenems for ESBL organisms

Nitrofurantoin and fosfomycin should NOT be used for pyelonephritis because they do not penetrate renal tissue adequately.  

4. Current Diagnostic Recommendations

In uncomplicated cystitis:

Urinalysis is often sufficient.

Typical findings:

• positive leukocyte esterase
• nitrites
• pyuria

Urine culture recommended when:

• recurrent UTIs
• pregnancy
• complicated infection
• pyelonephritis
• treatment failure
• resistant organisms suspected

5. Asymptomatic Bacteriuria

Do NOT treat unless:

• pregnant
• undergoing invasive urologic procedure

Do NOT routinely treat:

• elderly patients
• diabetics
• catheterized patients
• nursing home residents

6. Pregnancy UTI Guidelines

Pregnancy changes management significantly.

Safe/common options

• cephalexin
• amoxicillin-clavulanate
• fosfomycin
• nitrofurantoin (usually acceptable except near term)

Avoid/Use Caution

TMP-SMX

Avoid especially:

• 1st trimester
• near delivery

Nitrofurantoin

Avoid near term if possible because of neonatal hemolysis risk.

Pregnant women with bacteriuria generally SHOULD be treated even if asymptomatic.

7. Recurrent UTI Guidelines

Defined as:

• ≥2 UTIs in 6 months OR
• ≥3 UTIs in 12 months

Management:

• behavioral modifications
• vaginal estrogen in postmenopausal women
• postcoital prophylaxis
• low-dose suppressive antibiotics in selected patients

Common prophylactic agents:

• nitrofurantoin
• TMP-SMX
• cephalexin

8. Current Resistance/Stewardship Principles

Modern guidelines emphasize:

• shortest effective duration
• avoiding fluoroquinolones when possible
• tailoring therapy to culture results
• considering local antibiograms

Common organism:

• E. coli (~75–95%)

ESBL-producing organisms are increasingly common, especially in recurrent UTIs and healthcare-associated infections.

Practical Quick Reference

Condition

First-line

Simple cystitis

Nitrofurantoin 5 d

Alternative

TMP-SMX 3 d

Resistant risk

Fosfomycin once

Pyelonephritis

Fluoroquinolone or IV beta-lactam

Pregnancy

Cephalexin, Augmentin, fosfomycin

Asymptomatic bacteriuria

Treat only pregnancy/urologic procedure

If you want, I can also give:

• ER/urgent care UTI algorithms
• inpatient pyelonephritis guidelines
• correctional medicine UTI management
• catheter-associated UTI guidelines
• ESBL treatment recommendations
• step-by-step antibiotic selection tables
• current dosing adjusted for renal function
• UTI treatment pearls for boards/MKSAP/ABIM style questions

They sat in the smoky room. Cigar smoke filled the air. It was raining outside. He looked over at her. The light flickered above the table they were sitting at. He took a puff of his cigar and asked her, So what do you think it means? I don’t know what it means, honestly. It could mean a lot of things. My take, he said as he looked at her and then looked away, is that they’re after you. It’s a signal that they don’t respect you or me. She looked at his green military cap and his green military jacket. He wasn’t in the military, but he wore them. It wasn’t like Halloween, though. It was more like camouflage. Both were a solid green, like a tank. He looked like one of Che Guevara’s guerrillas. How’s that cigar, she asked. It’s pretty good. It’s a TB, whatever that is. Brocaw or Brady, she asked with a smile. Maybe a bit of both, he said. I guess I’m kind of like a reporter, the way I tell these stories. I needed a fresh start, though. I was getting tired of all the talk about dragons and other mystical, mystical, mythical beasts. She looked at him with her chin slightly tilted upward. He was gonna make it, wasn’t he? He really was. He wasn’t scared of anything. She knew it now. Nothing could stop him. Nothing would keep him from her. They were together already. She was a ghost viper to him, and he was a ghost viper to her. He wondered if it was raining in Miami. Miami rain is always the nicest, he thought. And then he said, She agreed. She nodded in agreement. Mm-hmm. I love it when it’s hot and raining. It’s only 61 degrees Fahrenheit here, he said. What is that in centigrade, she asked. Don’t you mean Celsius? He laughed. It’s not a laughing matter, she said. Most of the world uses centigrade or Celsius. It makes more sense, don’t you think? 100 degrees is the boiling point of water instead of 212 degrees, which makes no sense whatsoever. I guess that’s true. It probably has something to do with area code 213, though. He sometimes wondered about area codes and what they meant, besides the obvious of what area code it is. Why did they pick certain numbers for certain places? He often saw connections between the area code of a place and what he found there. Some people thought it was hocus pocus mumbo jumbo, but those who knew knew. It had to do with all that dragon stuff. I thought we left dragons behind, she said. I never leave my dragon behind, he laughed, looking at her. She was there in ghost viper with no shimmer. I can’t wait till we don’t have to do this anymore, she said. Me neither, he replied. He didn’t like repeating what she said, it sounded too much like the Hawaiian echo. It was always better just to take it out loud, whatever they were saying, and then transcribe it. He was pretty sure someone else was transcribing everything he said. He wondered what it was like on her end. Did she even bother to transcribe it herself, or did someone else do it for her? Must be nice, must be nice, he said.

Wild fox let the heifer out of the car. Wildfox let the heifer out of the car. He lit the cigarette. It was a spicy cigarette. It reminded him of when Joy told him that his skin was spicy when he was 18. How did she know his skin was spicy? Did she lick it? It was always fun when Joy got drunk. She loved to get drunk with Wildfox. Once in a while she would get drunk and grind her pussy on his dick. She loved to grind her pussy on his dick. She’d been doing it since they were both 18. They were the same age. There was nothing wrong with it. And they were only doing it when they were adults. It wasn’t even like they were having sex. It was just simulated sex while standing and gyrating to the songs that they were listening to. What was their favorite song? Clocks by Coldplay. They loved to grind to Clocks by Coldplay. Then they would play David Gray Babylon. That was another great song that they used to do. Do it to a dirty grinding that they would do. He loved holding her body against his. She felt so good in his arms. And her hair was so soft.

The wild fox laughed at the GRUS. They had no idea what they were fucking with. They had no idea what they were seeing. They were just hallucinating the future based on drugs they were doing. They liked to do cocaine, these GRUS. They liked to do marijuana, these GRUS. They liked to drink alcohol, these GRUS. But they don’t know what it means when they do these things and see visions of the future. They try to interpret things as if the GRUS are God’s chosen people to run the universe. But the GRUS are just shitfuck wannabes who never were anything and never will be anything. They wanted to kill the bulls, the four bulls. There’s no way you could kill those four bulls. The four bulls on the cards. Because there’s four more bulls on the cards. Both of them are cards. Both of them are bulls. One’s a bull once removed, and the other’s a bull currently. What’s a bull once removed? It’s a bull that went to the heat. You know when the bull goes to the heat, it turns into a bigger bull. And that bigger bull is good friends with CC. And you know how it all comes together. You know what I like to say when I pop that champagne? You know what I like to say when I pop a bottle of champagne? What do I like to say, CC? You like to do a countdown. 10, 9, 8, 7, 6, 5, 4, 3, 2, 1. Pop! NBA finals!

Wild Fox walked out of the house. He started the Jeep and they drove into speedy gas. They were now in speedy gas. Wild Fox opened the red bag. He looked at the cards that he’d gotten for CC. The butler, express lane butler heat, butler the mighty, butler butler, heat. My house bulls, my house bulls, select bulls, debut bulls. He then put on the rings, the Vishnu ring. It was time now, after the four Red Bulls had been seen and the four were heat, it was time, it was time. It was time to walk on the grass with no shoes. It was time to walk on the grass with no shoes. And so they got out and walked on the grass with no shoes. Woohoo! You know the team known as the Bulls.

Nous vivons une époque politique folle. Je me souviens d’un temps où personne ne parlait de sa politique ni de sa religion. Le monde était un endroit plus paisible. Puis le 11 septembre est arrivé et le monde est devenu merdique. La race et la religion sont devenues des raisons de considérer quelqu’un comme un terroriste. Je me souviens d’avoir conduit avec mon père dans l’Oldsmobile Silhouette pour aller faire une vidange le matin où c’est arrivé. J’étais malade ce jour-là. J’ai dû le vérifier. C’était un mardi.

We are living in a crazy political time. I remember when no one talked about their politics or religion. The world was a more peaceful place. Then 9/11 happened and the world turned to shit. Race and religion became the reasons to consider someone a terrorist. I remember driving with my dad in the Oldsmobile Silhouette to get an oil change the morning it happened. I was sick that day. I had to look it up. It was a Tuesday.