What Are The Chances Of Pregnancy In Women With Age 40 And Above?

HI I am at a loss. I have had 3 miscarriages and have had a hard time getting pregnant in the first place. I have a healthy 10 year old son. But I always wanted another one. I have tried everything and have been through a lot !! At 38, I was told my age was against me but I have friends who have had babies at 40. Is there any hope for me? I am 46 years old. Thank you