OBJECTIVE: Brucellosis is a zoonosis with high morbidity in humans. This disease has gained interest recently due to its re-emergence and potential for weaponization. Pregnant women with this disease can develop severe complications. Its association with adverse obstetric outcomes is not clearly understood. The objective of this study was to describe the obstetric outcomes of brucellosis in pregnancy. METHODS: Cases of pregnant women with active brucellosis seen at the Hospital Nacional Cayetano Heredia from 1970 to 2012 were reviewed. Diagnostic criteria were a positive agglutination test and/or positive blood/bone marrow culture. Presentation and outcomes data were collected. The Chi-square test was used for nominal variables. A p-value of <0.05 indicated significance. RESULTS: One hundred and one cases were included; 27.7% had a threatened abortion/preterm labor, 12.8% experienced spontaneous abortion, 13.9% preterm delivery, 8.1% fetal death, and 1.1% congenital malformations. There was one maternal death secondary to severe sepsis. After delivery, neonatal death occurred in 8.1%, low birth weight in 14.5%, and congenital brucellosis in 6.4%. The most common treatment was aminoglycosides plus rifampicin (42.2% of cases). Complication rates decreased if treatment was started within 2 weeks of presentation (p < 0.001). CONCLUSIONS: This is the largest series of brucellosis in pregnancy reported in the literature. Brucella presents adverse obstetric outcomes including fetal and maternal/neonatal death. Cases with unexplained spontaneous abortion should be investigated for brucellosis. Prompt treatment is paramount to decrease the devastating outcomes.