Tuberculosis (TB) testing is generally safe and recommended during pregnancy. TB is a bacterial infection primarily affecting the lungs, though it can impact other body parts. Despite concerns about medical procedures during pregnancy, healthcare professionals prioritize the well-being of both mother and baby. Early detection of TB is important for managing potential risks.
Types of TB Tests and Their Safety in Pregnancy
Two primary tests detect TB infection: the Tuberculin Skin Test (TST), also known as the Mantoux test, and Interferon-Gamma Release Assays (IGRAs), which are blood tests. The TST involves injecting a small amount of purified protein derivative (PPD) under the skin, usually on the forearm. A healthcare provider examines the injection site 48 to 72 hours later for a reaction, measuring any raised, firm area to determine a positive result. The TST is safe and reliable during pregnancy, as it uses no live bacteria and poses no risk to mother or fetus. Pregnancy does not affect its results.
Interferon-Gamma Release Assays (IGRAs), such as the Quantiferon-TB Gold and T-Spot.TB tests, are blood tests that measure the immune system’s response to specific TB proteins. A blood sample is drawn and analyzed in a laboratory to detect TB. IGRAs are also safe during pregnancy, involving no live bacteria or radiation. Unlike the TST, IGRA tests are not influenced by prior BCG vaccination, which can sometimes lead to false positive TST results. Both tests are valuable screening tools and pose no direct threat to the pregnant individual or baby.
Importance of TB Screening During Pregnancy
TB screening during pregnancy is important for the health of both mother and baby. Untreated active TB disease in pregnant individuals can lead to serious complications. Pregnant women with active TB have an increased risk of adverse maternal outcomes, including maternal death, anemia, increased antenatal admissions, and miscarriage.
For the baby, untreated maternal TB can result in low birth weight, premature birth, and in rare cases, congenital TB. Congenital TB, though uncommon, can be severe and potentially fatal for newborns. Early detection and treatment of TB during pregnancy prevent these outcomes, ensuring better health for mother and infant. Since some TB symptoms, such as fatigue or weight changes, can be similar to typical pregnancy symptoms, screening helps identify the infection promptly, even when a pregnant person may not realize they have TB.
What Happens After a Positive TB Test
A positive TB test result indicates exposure to TB bacteria, but not necessarily active TB disease. Following a positive test, further evaluation determines if the infection is latent TB infection (LTBI) or active TB disease. This evaluation typically includes a medical history, physical examination, and additional diagnostic tests.
A chest X-ray is often performed to check for active TB in the lungs. For pregnant individuals, this procedure is conducted with abdominal shielding to protect the fetus from radiation exposure. Sputum samples may also be collected for microscopic examination, culture, and drug-susceptibility testing to confirm active disease and guide treatment.
If latent TB infection is diagnosed, treatment may be delayed until after delivery, particularly for those with a lower risk of progressing to active disease, to minimize potential medication side effects during pregnancy. However, for individuals at high risk of progression, such as those with HIV or recent exposure, treatment for latent TB may begin during pregnancy, usually with isoniazid and supplemental pyridoxine (vitamin B6). For active TB disease, immediate treatment is recommended, typically involving a combination of medications like isoniazid, rifampin, and ethambutol, with careful monitoring to ensure safety for both mother and baby.