From the Guidelines
Tuberculosis (TB) skin tests are safe to administer during pregnancy, with no evidence of adverse effects on the pregnant mother or fetus. According to the American Thoracic Society and the Centers for Disease Control and Prevention, pregnancy has minimal influence on the pathogenesis of TB or the likelihood of latent TB infection (LTBI) progressing to disease 1. The current classification scheme for interpreting the Mantoux tuberculin skin test is likely valid in pregnancy, although it has not been verified in this group of women.
Some key points to consider when administering TB tests during pregnancy include:
- Pregnancy does not increase the risk of progression to disease, but certain conditions may promote hematogenous spread of organisms to the placenta 1
- The need for treatment of active TB during pregnancy is unquestioned, but the treatment of LTBI in pregnant women is more controversial 1
- Some experts prefer to delay treatment until after delivery due to the potential risk of isoniazid hepatotoxicity in pregnant women 1
- Proper abdominal shielding should be used during chest X-rays to minimize radiation exposure to the fetus
It is essential to target tuberculin skin testing to pregnant women with specific risk factors for LTBI or progression of LTBI to disease, such as previous TB exposure or HIV infection 1. Early detection and treatment of TB during pregnancy are crucial to prevent potential risks to both mother and baby. Most first-line TB medications are considered safe during pregnancy when properly prescribed and monitored by healthcare providers.
From the Research
TB Testing During Pregnancy
- A TB test can be performed during pregnancy if indicated by a TB evaluation, which consists of a TB risk assessment, medical history, physical examination, and a symptom screen 2.
- The tuberculin skin test is an acceptable screening test for TB in pregnant women, with more data supporting its use in pregnancy compared to interferon-gamma release assays 3.
- If a pregnant woman has signs or symptoms of TB or if the test result for TB infection is positive, active TB disease must be ruled out before delivery, with a chest radiograph and other diagnostics as indicated 2.
Interpretation of TB Test Results
- The interpretation of TB test results can be variable, with significant interobserver variability and a tendency to under-read around the cutoff point 4.
- The use of 5 TU PPD at 48 hours by a trained physician can aid in early and more reliable diagnosis of TB 4.
- The Mantoux test has low accuracy in the diagnosis of doubtful cases of cutaneous tuberculosis, with a sensitivity and specificity of 58.97 and 62.50%, respectively, using a cut-off of 10 mm 5.
Treatment of Latent TB Infection During Pregnancy
- Most women will not require latent TB infection treatment while pregnant, but all require close follow up and monitoring 2.
- Treatment of latent TB infection should be deferred until 3 months postpartum, except in those severely immunosuppressed, human immunodeficiency virus positive, or recently exposed 3.
- Isoniazid with pyridoxine for 9 months is preferred for the treatment of latent TB infection, with reasonable safety in pregnancy and breastfeeding 3.