The only thing I can think of is that you said she was gaining weight, extra weight can put a strain on you knees and back. I would suggest exercises for the back and knees and that should also help with the weight. My hubbys back has been hurting and he got one of those exercise balls and does some back exercises every other morning and it no longer is hurting. Sorry I couldnt be more helpful, just a thought, maybe some of these wonderful ladies have some insight to help you and your wife out. Best of luck!
Jen
Have her doctor do a thyroid test. It is a simple blood test and if it comes back at an abnormal level then they will do a complete thyroid work-up. ALOT of women get thyroid disease (hypothyroidism (under-active thyroid) or hyperthyroidism (over-active), after giving birth. It usually goes undiagnosed because the symptoms are usually very close to what you would expect for post-partum symptoms. Signs/symptoms of hypothyroidism are fatigue, depression, muscle aches, hair loss, dry skin, cold intolerance, poor memory, and an inability to lose weight. Signs/symptoms of hyperthyroidism are tiredness, irritability, nervousness, feeling very warm, increased sweating, and insomnia. Alot of times the thyroid will eventually correct itself but she may need medication to help her until that happens.
Take Care
When you give birth you use muscles and such things you did not know existed------as far as the weight gain----she would not have post-partum depression would she-----I know when you are in a depressed state you gain weight------I know that first hand---and post-partum is very sneaky-----take care!