TB Skin Testing During Pregnancy
Safety of TB Skin Testing in Pregnancy
- The American Thoracic Society recommends that TB skin testing is safe during pregnancy and has no adverse effects on the pregnant mother or fetus 1, 2
- The tuberculin skin test (TST) has been extensively studied in pregnancy and there is no evidence that it causes any harm to the pregnant woman or her unborn child 1, 3
- Pregnancy has minimal influence on the pathogenesis of TB or the likelihood of latent TB infection (LTBI) progressing to active disease 2
Interpretation of TB Skin Test Results During Pregnancy
- The standard interpretation criteria for TB skin testing apply during pregnancy, with a positive result defined as ≥5 mm induration in high-risk individuals, ≥10 mm induration in moderate-risk individuals, and ≥15 mm induration in low-risk individuals 4
- While one study demonstrated a decrease in lymphocyte reactivity to tuberculin during pregnancy, other studies have not shown any effect of pregnancy on cutaneous delayed hypersensitivity to tuberculin 1
Recommendations for TB Screening During Pregnancy
- Pregnant women should be targeted for tuberculin skin testing only if they have specific risk factors for LTBI or for progression of LTBI to disease 1, 3
- If a pregnant woman has a positive TB skin test, a chest radiograph with appropriate shielding should be performed to exclude active TB, even during the first trimester 5
Follow-up After Positive TB Skin Test
- If chest radiographs are normal and no symptoms of active TB are present, tuberculin-positive pregnant women may be candidates for treatment of LTBI 5
- Treatment decisions for LTBI during pregnancy should balance the risk of isoniazid hepatotoxicity against the risk of developing active TB and its consequences for both mother and child 6
- For women at high risk for progression to active TB, treatment should not be delayed based on pregnancy alone 1