Screening obstetric patients for tuberculosis in communities with a high prevalence is an important part of a comprehensive tuberculosis control program. Until the 1970s, routine prenatal screening usually included a chest roentgenogram, but several studies demonstrated the low yield and high cost of such a policy and it is no longer recommended. Currently, many obstetrics textbooks and experts on tuberculosis recommend routine prenatal tuberculosis screening with a tuberculin skin test (TBN-ST), reserving the use of a chest roentgenogram for those with pulmonary symptoms or a positive TBN-ST. There are compelling reasons for the use of a TBN-ST as part of routine prenatal screening in high-risk populations. The most obvious is to detect active tuberculosis in the mother and prevent the potentially serious consequences of transmission to the infant during the neonatal period. Routine prenatal screening also has a rational basis because virtually all of the tuberculin reactors identified will be less than 35 years of age and, therefore, are candidates for isoniazid prophylaxis. Additionally, it allows screening of a large, healthy population that may not otherwise come into contact with the health care system.
The University of California, San Diego Medical Center, services a large number of Hispanic and Southeast-Asian patients, most of which are from inner-city neighborhoods that have a low access to health care. Because of the high rate of tuberculosis in San Diego generally, and in this patient group specifically, a TBN-ST is a routine component of prenatal screening. Approximately 25 percent (about 1,000a year) of the women presenting to the University of California, San Diego Medical Center for delivery have not had prenatal care and thus have not had a TBN-ST. It has become standard practice to discharge women from the hospital on the first postpartum day, preventing skin testing while the patient is in the hospital, because a 48-h reading cannot be obtained.