Hi,
I'm 44 and on the countdown to baby no.1, before that I had a mc in August 2009 and two possible chemicals, so please don't give up hope!
Your body can change alot in a few years, so something that wasn't a major issue at 30 might be the reason for a problem at 40. In my case, we discovered that I had underactive thyroid and I also took metformin for pCOS, once that medication was all adjusted, I got pregnant and am now hoping to have baby towards the end of February. I would ask your GP to run the routine blood tests (thyroid, iron, etc), also, take a good look at your overall health -- could you lose weight? (I did from a BMI of 40 (yes, I know....) to a BMI of 29/30), try and incorporate some gentle excerise, try to eat a little healthier and I also did acupuncture for pre-IVF, but got pregnant naturally! Oh, and I quit smoking (quit when I was pregnant before, but depressed at mc and started again)....I didn't go crazy with loads of exercise, no drinking, etc., but generally, more healthy....
In fact, I am healthier now at 44 than I was at 34, so in my case, the 'golden oldie' got lucky, so there is no reason why you can't have another baby, but take care of yourself regardless....any loss is hard
best wishes