Low IgG avidity for Toxoplasma gondii in consecutive pregnancies

Abstract

Objective: To present a clinical case of a pregnant woman who consistently showed low avidity IgG test results for Toxoplasma gondii in two consecutive pregnancies. Case details: G5P2A2, 41 years old, followed up in the High-Risk Prenatal Care due to serologies for T. gondii with IgM+/IgG+ and avidity test performed at 11 weeks of gestation, showing 49% avidity. She brought exams from the previous pregnancy that also showed serologies for T. gondii with IgM+/IgG+ and low IgG avidity (42%). The fetus was evaluated at the Fetal Medicine outpatient clinic and showed no ultrasonographic abnormalities. The pregnancy progressed to spontaneous vaginal delivery at 38 weeks, resulting in a healthy newborn. Final considerations: The importance of the avidity test in managing gestational toxoplasmosis and the diagnostic limitations when low avidity is present in isolation is noted. It is suggested to standardize effective medical records across health services to allow tracking the serological history of pregnant women, in addition to training professionals in clinical protocols, such as the Technical Note (NT) N^o 100/2022 do Ministry of Health, to avoid unnecessary treatments.