TB Testing During Pregnancy and Breastfeeding
Yes, TB testing is safe during pregnancy and breastfeeding, and should be performed when indicated by specific risk factors. 1
Safety of TB Testing in Pregnancy
- The tuberculin skin test (TST) has no adverse effects on the pregnant mother or fetus and has been extensively studied with an excellent safety record. 2, 1
- Pregnancy does not alter the interpretation of TST results—the standard classification scheme (≥5 mm for high-risk, ≥10 mm for moderate-risk, ≥15 mm for low-risk individuals) remains valid. 2, 1
- While one older study suggested decreased lymphocyte reactivity to tuberculin during pregnancy, multiple other studies have not confirmed any effect of pregnancy on skin test responses. 2, 1
When to Perform TB Testing in Pregnancy
Pregnant women should be targeted for TB testing only if they have specific risk factors—universal screening is not recommended. 2, 1
Risk factors warranting TB testing include:
- Close contact with someone who has active TB 3
- Symptoms suggestive of TB disease 4, 3
- HIV infection or other immunocompromising conditions 4
- Immigration from high TB-burden countries 3
- High-risk medical conditions that increase progression risk 4
Follow-Up After Positive TB Test
- If a pregnant woman tests positive for TB, a chest radiograph with appropriate abdominal shielding should be performed immediately to exclude active disease, even during the first trimester. 2, 1
- If the chest radiograph is normal and no symptoms are present, the woman has latent TB infection (LTBI) and treatment decisions should be individualized based on her risk profile. 1
- For high-risk women (recent infection, HIV-positive, or other conditions promoting progression), treatment should not be delayed based on pregnancy alone, though careful monitoring for isoniazid hepatotoxicity is essential. 2, 1
TB Testing During Breastfeeding
- TB testing is safe during breastfeeding and poses no risk to the nursing infant. 2
- The small amounts of anti-TB medications that pass into breast milk do not cause toxicity in newborns, so breastfeeding should not be discouraged in women being treated for TB. 2
- However, medications in breast milk should not be considered effective treatment or prophylaxis for the infant. 2
- Women taking isoniazid while breastfeeding should receive pyridoxine supplementation (25 mg/day). 2
Important Caveats
- The key pitfall is failing to test pregnant women with clear risk factors due to unfounded concerns about test safety—delayed diagnosis of active TB poses far greater risks to both mother and fetus than the testing itself. 4
- If active TB is suspected based on symptoms or radiographic findings, do not delay diagnostic evaluation including sputum examination. 2, 4
- Treatment of active TB during pregnancy should be initiated immediately when diagnosed, as untreated TB poses significant morbidity and mortality risks that far exceed medication risks. 2, 5, 4