Effect of antenatal spiramycin treatment on the frequency of retinochoroiditis due to congenital toxoplasmosis in a Colombian cohort

Abstract

Gestational toxoplasmosis is frequent and severe. There is still debate about the benefits of treatment against ocular manifestations in the newborn. Spiramycin treatment is used for this purpose, unfortunately prenatal diagnosis is sometimes delayed and pregnant women are not treated. To describe the relationship between treatment with spiramycin during pregnancy in mothers with gestational toxoplasmosis and development of ocular toxoplasmosis in newborns. We conducted a descriptive study of a case series. We evaluated a prospective cohort of patients diagnosed with gestational toxoplasmosis during three years at the Retinology Service at the Clínica Universitaria Bolivariana in Medellín. Gestational toxoplasmosis was found in 23 mothers; 15 (65%) were treated during pregnancy with 3 g per day of spiramycin, eight (35%) patients were untreated. In the treated group just one newborn developed ocular toxoplasmosis (6.6%), in contrast with five (62.5%) of the eight patients who did not receive treatment. These results suggest that pregnancy treatment reduces the relative risk of ocular toxoplasmosis in the newborn by 96% (95% CI: 33 - 100%). Only two (14%) of the patients who were evaluated, had nervous system involvement related to toxoplasmosis in CT scan or cerebral ultrasound. These two patients also developed ocular pathology and were diagnosed at the time of birth, so they did not received antenatal treatment. A protective effect was found against the ocular involvement in patients whose mother received treatment with spiramycin (OR=0.04;95% CI: 0.00-0.67), p<0.01 (Fisher's Exact Test).