Clinical management of Toxoplasma gondii serology in pregnancy
Year: 2026
Type: article
Abstract: Objective To examine how Toxoplasma gondii serological findings, including IgG avidity and IgM persistence, informed clinical management decisions in a tertiary obstetric setting. Methods This retrospective cohort study included pregnant women who underwent T. gondii serological testing from January 2016 to January 2026. During this period, T. gondii IgM testing was performed in 8,676 pregnant women. The final cohort comprised 212 women with abnormal or clinically uncertain serology and available detailed clinical data, including those with positive or equivocal IgM results and women with negative IgM and positive or equivocal IgG who underwent IgG avidity testing because the timing of previous infection remained uncertain, particularly in early pregnancy when pre-pregnancy serostatus was unavailable. Data extracted from medical records included demographics, obstetric characteristics, serology, clinical management, amniocentesis, amniotic fluid polymerase chain reaction (PCR), repeat IgM testing, and available pregnancy or neonatal outcomes. Analyses were primarily descriptive, with exploratory comparisons across predefined serological groups. Results The initial IgM result was positive in 130 women (61.3%), equivocal in 36 (17.0%), and negative in 46 (21.7%). Among 150 women with positive or equivocal IgM and positive or equivocal IgG, IgG avidity was high in 80 (53.3%), low in 36 (24.0%), and intermediate or equivocal in 34 (22.7%). Overall, 79 women (37.3%) underwent infectious disease consultation, 73 (34.4%) received antiparasitic treatment, 70 (33.0%) underwent detailed fetal ultrasound assessment, and 25 (11.8%) underwent amniocentesis with amniotic fluid PCR testing. Treatment was most frequent in the low-avidity group (29/36, 80.6%), whereas amniocentesis with PCR was most frequent in the intermediate or equivocal avidity group (12/34, 35.3%). Among the 16 cases with clear PCR documentation, no positive amniotic fluid PCR result was recorded; documentation was unavailable or unclear in 9 of 25 cases. Repeat IgM testing was performed in 90 of 166 women with positive or equivocal initial IgM results (54.2%), and documented persistent IgM positivity was present in 45 (27.1%). Among women with available duration data, the low-avidity group had the longest median duration of IgM positivity, reaching 150.0 days. Conclusion Positive or equivocal T. gondii IgM results during pregnancy should not be interpreted as evidence of acute infection in isolation. High IgG avidity was common among women with positive or equivocal IgM results, whereas low avidity was associated with more frequent treatment and intermediate/equivocal avidity with more frequent invasive testing. These findings suggest that avidity-guided interpretation of toxoplasma serology, integrated with gestational age and clinical context, may reduce unnecessary treatment and invasive procedures during pregnancy.
Source: BMC Pregnancy and Childbirth
Language: English
Subfield: Parasitology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,290
OpenAlex ID: W7222963516
FWCI:
Cites:
Cited by:
Related to: