Antitubercular Treatment in Pregnancy
Recommended First-Line Regimen
Pregnant women with active tuberculosis should be treated immediately with isoniazid, rifampin, and ethambutol, without delay regardless of trimester, as untreated TB poses far greater risks to mother and fetus than the medications. 1
- The standard regimen consists of isoniazid (5 mg/kg up to 300 mg daily), rifampin (10 mg/kg up to 600 mg daily), and ethambutol (15-25 mg/kg daily) for the initial 2-month phase 1, 2
- After the initial phase, continue isoniazid and rifampin for an additional 7 months (total 9 months) if pyrazinamide is not used 1
- All pregnant women receiving isoniazid must receive pyridoxine (vitamin B6) 25 mg daily to prevent peripheral neuropathy 1, 3
Critical Medications to Avoid
Streptomycin and all aminoglycosides (kanamycin, amikacin) are absolutely contraindicated in pregnancy as they cause congenital deafness in approximately 17% of exposed fetuses 1, 4
- Pyrazinamide is generally not recommended in the United States during pregnancy due to insufficient teratogenicity data, though WHO recommends its use internationally 1, 5
- If pyrazinamide is excluded, treatment duration must extend to 9 months minimum 1
- Fluoroquinolones should be avoided due to arthropathy concerns in animal studies 1
Treatment Timing and Initiation
Treatment should begin immediately upon diagnosis, even during the first trimester, as untreated tuberculosis carries higher maternal and fetal mortality risk than medication exposure 1, 6
- For women with latent TB infection (LTBI) rather than active disease, some experts recommend delaying treatment until after the first trimester if progression risk is low 7
- However, for HIV-infected pregnant women or those with recent TB exposure, LTBI treatment should not be delayed even in the first trimester 7
Monitoring Requirements
Baseline liver function tests are mandatory for all pregnant women starting TB treatment, as pregnancy (particularly the postpartum period within 3 months) may increase vulnerability to isoniazid hepatotoxicity 1, 2
- Perform monthly clinical evaluations checking specifically for hepatotoxicity symptoms: fever, malaise, vomiting, jaundice, and abdominal pain 2
- Instruct patients to stop all medications immediately and seek urgent evaluation if any hepatotoxicity symptoms develop 2
- Repeat liver function testing at 2,4, and 8 weeks if using combination therapy 7
Breastfeeding Considerations
Breastfeeding should continue without interruption during TB treatment, as first-line drugs appear in breast milk at concentrations too low to cause infant toxicity 1, 2
- The infant must also receive pyridoxine supplementation even though drug concentrations in breast milk are subtherapeutic 8
- Medications in breast milk cannot treat or prevent TB in the infant—if the infant requires treatment, full therapeutic doses must be prescribed separately 8, 2
Drug-Resistant Tuberculosis
For multidrug-resistant TB (MDR-TB), expert consultation is essential as treatment must be individualized based on susceptibility patterns 1
- Ciprofloxacin has the best safety profile among second-line agents if fluoroquinolone use becomes necessary 3
- For contacts of isoniazid-resistant cases, consider rifampin-based regimens 7
Common Pitfalls to Avoid
- Never delay treatment waiting for the second trimester in high-risk patients (HIV-infected, recent converters, or active disease) 7, 1
- Never use streptomycin under any circumstances in pregnancy 1, 4
- Never assume pregnancy increases TB disease severity—it does not, but hepatotoxicity risk may be higher 1, 3
- Termination of pregnancy is not medically indicated for women taking first-line TB drugs 1, 4
- Do not forget pyridoxine supplementation—this is mandatory, not optional 1, 3