Background For a pregnant woman and her child, untreated tuberculosis (TB) involves a higher risk than the treatment itself. While the drugs used in the initial treatment of tuberculosis cross the placenta, they do not appear to have harmful effects on the fetus.

Purpose To describe the use of TB treatment in a pregnant patient with a diagnosis of tuberculosis during the first trimester. To demonstrate the degree of causality following the tragic consequences.

Material and methods A woman aged 33 years was admitted because of the appearance of a right supraclavicular adenopathy conglomerate with a compatible TB diagnosis following lymph node biopsy. Oral treatment was started with rifampicin 10 mg/kg/day, isoniazid 5 mg/kg/day and pyrazinamide 20 mg/kg/day. Naranjo´s algorithm was applied in order to determine the grade of causality between the adverse event and tuberculostatic use.

Results Controls of internal medicine a month after starting treatment showed good tolerance with reduced adenopathic conglomerate. A positive pregnancy test after 48 days of treatment was calculated from her last menstrual period. Pyrazinamide was suspended but we decided to continue with rifampicin and isoniazid until week 13 of gestation, when the woman was admitted to gynaecology for abdominal ultrasound, which showed a severe cephalic malformation, compatible with fetal acrania. Voluntary termination of the pregnancy was performed. The Naranjo score assigned a probability of 3 points, classified as possible.

Conclusion Both the American Thoracic Society and the Centre for Disease Control and Prevention recommend the use of some anti-TB treatment during pregnancy because untreated TB represents a much greater danger to a pregnant woman and to her fetus. Furthermore, studies show that the use of some anti-TB that cross the placenta, such as isoniazid and rifampicin, can result in fetal malformations, especially during the first trimester.

References and/or Acknowledgements Maria del Carmen Gálvez

No conflict of interest.