One of the health concerns has to do with decreased bone density. (myorganicformula.com)
Perhaps cats need to be included in the space program, where decreased bone density is a known problem? (vetbabble.com)
Here are some with the negative reasons for not employing Depo - Provera: it can cause decreased bone density which can lead to osteoporosis, depression, increased blood clots, liver damage, headaches, hair loss, leg cramps, nervousness, dizziness, abdominal bloating, and weight gain. (createyourgreatlife.com)