You must have misread, I’m no expert - just a biologist who tried to make an educated decision on when to spay my lab. Happy to cite sources though - looking again, the study I found most robust is longitudinal rather than Cochrane but had a very large data set which was my interest.

This for example helped me to decide to leave my spay until after 11 months.

www.ncbi.nlm.nih.gov/pmc/articles/PMC7359819/

Feel free to share yours, it’s been a couple of years since I dug through research pieces, sharing information and forming educated opinions is key for good science.