Pros and Cons of paying your wife to have a child.?

My wife and I are happily married. Thankfully, she has already giving me a beautiful son who is now 18 months old. I desperately want a second child, but she doesn't want to, because of the strain that the pregnancy put on her body and she had to have a c-section. Furthermore, she is really into her physical apparence, she had to work hard to get back in shape. However, I know that my wife loves money. I am wondering would it be misguided to offer her money to have a second child. P.S. She is turning 40 in December.