It could be any number of things. Here's a list of a few common causes:
PCOS (Polycystic Ovarian Disease
) It's a common cause of infertility
and it's easy to treat. (Not releasing eggs)
There could be something blocking your tubes, such as a clot. An HSG could determine and help with that.
Your hubby could have a low sperm count
or his boys might be swimming the wrong way. He could also have an infection (like bacterial) which is causing a problem.
Your egg quality might be low.
You could have a uterine problem (like misshaped)
There are too many possibilities. Go see your doctor. I did and it worked!
After reading your other questions, I wanted to add:
Are you sure that the strokes and the coumadin
don't have anythign to do with this? If you've had strokes, you'll definately need to see a doc before getting preggy just in case it puts too much stress
on your body.