[gemy]

I have had a female go into heat at 7mths old and one at 9 months old. Growth plates on small breed dogs can close as early as 7-8 months old. The last growth plate to close is the tibial plateau. A lateral view of the knee joint confirms if this growth plate has closed.


Most vets like to spay at 6mths old prior to a first heat. Pyrometra is very rare in a young dog, as is mastitis or breast cancer.