This nationwide Swedish cohort study (n=3,666,002 births, 1987–2021) examined whether clinically diagnosed congenital TORCH infections (CMV, toxoplasmosis, rubella, HSV, syphilis; n=975 exposed) were independently associated with intellectual disability (ID), autism, ADHD, OCD, tic disorders, nonaffective psychosis, and school grades at age 16, using both population-level Cox regression and sibling-comparison models to control for familial confounding.
Congenital TORCH infection was strongly associated with ID (HR 7.22; 95% CI 6.14–8.49) and autism (HR 3.10; 95% CI 2.55–3.76); sibling comparisons yielded similar or larger estimates (ID: HR 11.28; autism: HR 3.19), ruling out shared familial factors as the explanation. Risk scaled with ID severity (mild HR 3.01 to severe/profound HR 23.51), and exposed individuals scored 1.50 points lower on standardized school grades. ADHD associations attenuated in sibling analyses; OCD showed no consistent association. CMV drove the largest signal (autism HR 4.57; ID HR 10.84 in adjusted models).
TORCH diagnoses came from clinical registers, likely undercounting mild or asymptomatic cases (ascertainment bias). Only 975 exposed individuals were identified over 35 years, limiting power for pathogen-specific and rare-outcome analyses. Diagnostic methods changed across the study period (culture pre-1993, then PCR), introducing temporal heterogeneity.
Clinicians should counsel that congenital TORCH infections — especially CMV — carry a substantially elevated risk of ID and autism that persists after accounting for family background, reinforcing the importance of antenatal screening and preventive strategies (e.g., CMV hygiene counseling, rubella vaccination). Children diagnosed with congenital TORCH should be followed proactively for neurodevelopmental disorders, including academic difficulties even in the absence of a formal diagnosis.
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