Congenital Cytomegalovirus Infection in Children with Autism Spectrum Disorder: Systematic Review and Meta-Analysis.

Maeyama et al. (2018) looked at every paper linking congenital CMV and autism. They found only three tiny studies. They pooled the numbers to see how strong the link might be.

The pooled odds ratio was 11.31. That sounds huge. But only a handful of kids had both CMV and autism. The authors say the evidence is still shaky.

Two of the three studies are old case series. Yamashita et al. (2003) saw autism in 2 of 7 CMV kids. Matson et al. (2004) saw 3 cases. Both papers are inside the new meta, so the big number just re-packages their small samples.

Other reviews find smaller but firmer links. Robinson et al. (2011) showed neonatal jaundice raises autism odds only 1.43 times. Pu et al. (2013) found the MTHFR gene lifts odds about 1.4 times. These studies had more people, so their lower odds are probably more real.

No study contradicts CMV as a risk factor. The clash is about certainty. Tiny samples give flashy odds but little trust. Larger studies give modest odds that hold up.

For now, keep CMV in your medical history checklist, but do not panic parents. If a child has both autism and known CMV, document it for the team. Push for bigger studies instead of new tests.