Maternal Acute Toxoplasmosis and Risk of Vertical Transmission to the Fetus: A Prospective Study Among Pregnant Women

• Sarah Omar Alati

  Department of Medical Parasitology, Faculty of Medicine, Al-Asmarya Islamic University

  Author

  https://orcid.org/0009-0009-8763-624X

Background: Primary Toxoplasma gondii infection during pregnancy can cross the placenta and cause congenital toxoplasmosis, yet the evidence on prevalence, diagnosis, transmission, and fetal outcomes is fragmented and varies by region. Objective: To critically review recent international studies on (1) the prevalence and serological profile of acute maternal infection, (2) gestational age and vertical transmission, (3) maternal and pregnancy-related factors, and (4) fetal outcomes with ultrasonographic and molecular findings. Methods: A narrative critical review of about 30 peer-reviewed studies, mainly published in 2020–2025, appraised by design, population, diagnostic criteria, findings, and limitations. Results: Pooled seroprevalence in pregnant women was roughly 33–43% across global, Eastern Mediterranean, and African meta-analyses, with very high heterogeneity; acute infection was much rarer (about 1.1% worldwide). IgM alone overestimates recent infection, whereas combining IgM, IgG avidity, and IgA classifies infection timing better. Transmission risk rises with gestational age, but fetal disease is more severe after early infection. Dietary and cat-related exposures are linked to maternal infection; their independent role in fetal transmission is unproven. Prenatal treatment is associated with lower transmission in observational studies, though selection bias limits interpretation. Amniotic-fluid PCR showed pooled sensitivity of about 85% and specificity near 100%; ultrasound signs were non-specific, and a normal scan did not exclude infection. Conclusions: Suspected acute toxoplasmosis in pregnancy needs an integrated pathway: serology, gestational age, fetal ultrasound, PCR when indicated, and postnatal follow-up. Few studies link all these steps in one cohort using standard definitions of congenital infection.

Bigna, J. J., Tochie, J. N., Tounouga, D. N., Bekolo, A. O., Ymele, N. S., Youda, E. L., Sime, P. S., & Nansseu, J. R. (2020). Global, regional, and country seroprevalence of Toxoplasma gondii in pregnant women: A systematic review, modelling and meta-analysis. Scientific Reports, 10, 12102. https://doi.org/10.1038/s41598-020-69078-9

Buonsenso, D., Pata, D., Turriziani Colonna, A., Iademarco, M., De Santis, M., Masini, L., Conti, G., Molle, F., Baldascino, A., Acampora, A., Luciano, R., Gallini, F., & Valentini, P. (2022). Spiramycin and trimethoprim-sulfamethoxazole combination to prevent mother-to-fetus transmission of Toxoplasma gondii infection in pregnant women: A 28-years single-center experience. The Pediatric Infectious Disease Journal, 41(5), e223–e227. https://doi.org/10.1097/INF.0000000000003469

Fricker-Hidalgo, H., Cimon, B., Chemla, C., Dardé, M.-L., Delhaes, L., L’Ollivier, C., & Villena, I. (2020). Toxoplasma gondii-specific IgG avidity testing in pregnant women. Clinical Microbiology and Infection, 26(11), 1480–1484. https://doi.org/10.1016/j.cmi.2020.04.012

Mandelbrot, L., Kieffer, F., Sitta, R., Laurichesse-Delmas, H., Winer, N., Mesnard, L., Berrebi, A., Le Bouar, G., Bory, J.-P., Cordier, A.-G., Ville, Y., Perrotin, F., Biquard, C., d’Ercole, C., Houfflin-Debarge, V., Villena, I., Thiébaut, R., & TOXOGEST Study Group. (2018). Prenatal therapy with pyrimethamine + sulfadiazine vs spiramycin to reduce placental transmission of toxoplasmosis: A multicenter, randomized trial. American Journal of Obstetrics and Gynecology, 219(4), 386.e1–386.e9. https://doi.org/10.1016/j.ajog.2018.05.031

Rabaan, A. A., Uzairue, L. I., Alfaraj, A. H., et al. (2023). Seroprevalence, risk factors and maternal-fetal outcomes of Toxoplasma gondii in pregnant women from WHO Eastern Mediterranean Region: Systematic review and meta-analysis. Pathogens, 12(9), 1157. https://doi.org/10.3390/pathogens12091157

Romand, S., Wallon, M., Franck, J., Thulliez, P., Peyron, F., & Dumon, H. (2001). Prenatal diagnosis using polymerase chain reaction on amniotic fluid for congenital toxoplasmosis. Obstetrics & Gynecology, 97(2), 296–300. https://doi.org/10.1016/S0029-7844(00)01118-2

Rostami, A., Riahi, S. M., Contopoulos-Ioannidis, D. G., Gamble, H. R., Fakhri, Y., Nourollahpour Shiadeh, M., Foroutan, M., Behniafar, H., Taghipour, A., Maldonado, Y. A., Mokdad, A. H., & Gasser, R. B. (2019). Acute Toxoplasma infection in pregnant women worldwide: A systematic review and meta-analysis. PLoS Neglected Tropical Diseases, 13(10), e0007807. https://doi.org/10.1371/journal.pntd.0007807

Souza, I. M. F. N. B. de, Siqueira, V. da S., Ribeiro, I. da C., Moraes, L. S. P., Prado, D. P. G. do, Rezende, S. R., Costa, W. L. G. da, & Rezende, H. H. A. (2023). Molecular and serological diagnosis of toxoplasmosis: A systematic review and meta-analysis. Revista do Instituto de Medicina Tropical de São Paulo, 65, e19. https://doi.org/10.1590/S1678-9946202365019

Tork, M., Sadeghi, M., Asgarian-Omran, H., Basirpour, B., Ahmadi, S., Ghasemzadeh, F., Sarvi, S., Gholami, S., Hosseini, S. A., Daryani, A., & Aghayan, S. A. (2025). Assessment of simultaneous IgM, IgG avidity, and IgA testing in diagnosis of acute toxoplasmosis in pregnant women: A systematic review and meta-analysis study. [Journal details to be verified from the final publisher record].

Wallon, M., Peyron, F., Cornu, C., Vinault, S., Abrahamowicz, M., Kopp, C. B., Binquet, C., & the Toxoplasmosis Group. (2013). Congenital toxoplasma infection: Monthly prenatal screening decreases transmission rate and improves clinical outcome at age 3 years. Clinical Infectious Diseases, 56(9), 1223–1231. https://doi.org/10.1093/cid/cit032

Wehbe, K., Pencole, L., Lhuaire, M., Sibiude, J., Mandelbrot, L., Villena, I., & Picone, O. (2022). Hygiene measures as primary prevention of toxoplasmosis during pregnancy: A systematic review. Journal of Gynecology Obstetrics and Human Reproduction, 51(3), 102300. https://doi.org/10.1016/j.jogoh.2021.102300

Araujo, R. D., et al. (2020). Treatment of acute toxoplasmosis in pregnancy: Influence in the mother-to-child transmission. Journal of Obstetrics and Gynaecology Canada. https://doi.org/10.1016/j.jogc.2020.04.021

Carlier, Y., et al. (2022). Congenital toxoplasmosis: The state of the art. Frontiers in Pediatrics, 10, 894573. https://doi.org/10.3389/fped.2022.894573

Codaccioni, C., Picone, O., Lambert, V., et al. (2020). Ultrasound features of fetal toxoplasmosis: A contemporary multicenter survey in 88 fetuses. Prenatal Diagnosis, 40(13), 1741–1752. https://doi.org/10.1002/pd.5756

Franco, J. R., et al. (2024). Systematic review and meta-analysis of congenital toxoplasmosis diagnosis: Advances and challenges. Journal of Tropical Medicine, 2024, 1514178. https://doi.org/10.1155/2024/1514178

Fricker-Hidalgo, H., Cimon, B., Chemla, C., Dardé, M.-L., Delhaes, L., L’Ollivier, C., & Villena, I. (2020). Toxoplasma gondii-specific IgG avidity testing in pregnant women. Clinical Microbiology and Infection, 26(11), 1480–1484. https://doi.org/10.1016/j.cmi.2020.04.012

Mulu Gelaw, Y., et al. (2024). Toxoplasma gondii seroprevalence among pregnant women in Africa: A systematic review and meta-analysis. BMC Infectious Diseases. https://pubmed.ncbi.nlm.nih.gov/38781272/

Rabaan, A. A., Uzairue, L. I., Alfaraj, A. H., et al. (2023). Seroprevalence, risk factors and maternal-fetal outcomes of Toxoplasma gondii in pregnant women from WHO Eastern Mediterranean Region: Systematic review and meta-analysis. Pathogens, 12(9), 1157. https://doi.org/10.3390/pathogens12091157

REIV-TOXO Project. (2024). Results from a Spanish cohort of congenital toxoplasmosis (2015–2022): The beneficial effects of prenatal treatment on clinical outcomes of infected newborns. [Journal details to be verified from the final publisher record].

Teimouri, A., Mohtasebi, S., Kazemirad, E., & Keshavarz, H. (2020). Role of Toxoplasma gondii IgG avidity testing in discriminating between acute and chronic toxoplasmosis in pregnancy. Journal of Clinical Microbiology, 58(9), e00505-20. https://doi.org/10.1128/JCM.00505-20

Tork, M., Sadeghi, M., Asgarian-Omran, H., et al. (2025). Assessment of simultaneous IgM, IgG avidity, and IgA testing in diagnosis of acute toxoplasmosis in pregnant women: A systematic review and meta-analysis study. BMC Pregnancy and Childbirth. https://doi.org/10.1186/s12884-025-07580-6

Walana, W., Odai, S. A., & Tamomh, A. G. (2025). Prevalence, risk factors, diagnosis and outcomes of Toxoplasma gondii infection in pregnancy: A review. Parasitology International, 103143. https://doi.org/10.1016/j.parint.2025.103143

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