This topic seems to come up a lot on a variety of forums. It really saddens me to think that women are blaming themselves for not being pregnant because they want it too much, or are too stressed.
This is a response I posted to the same exact question in the ltttc forum. I just copied and pasted.
"Nope. Not at all.
Women get pregnant after rape. Women get pregnant in abusive relationships. Women that are homeless get pregnant. Women living in areas of warfare get pregnant. Women that have 12 kids and can't afford to feed them get pregnant.
If stress is causing you not to ovulate, then yes, stress will interfere.
If you are ovulating, your body does not care what you are thinking about. The sperm and the egg aren't forming some master plan to prevent implantation simply because it's being thought about too much. And the embryo isn't waiting around until it senses PMA to implant. You can have a negative attitude and get pregnant as well.
In fact, until the past 100 years or so, lack of birth control was a HUGE issue for the world's female population. Maternal mortality rates were quite high. Women couldn't feed their children and faced the risk of dying from pregnancy/birth complications. If these women could have stressed themselves into preventing pregnancy, they would have done it. In fact, ancient Egyptians used to make a paste with crocodile dung and insert it into the vagina to try to prevent pregnancy.
If you could stress about it and prevent pregnancy, that would be WAY better birth control than crocodile dung!
"
Very relaxed and mellow people go through infertility. In fact, for the first 10 months of my ttc experience, I was very relaxed and had a great attitude. It was stress free basically. Why didn't it happen then? Same thing with my first pregnancy. In fact, with that pregnancy, I was going through IUI for the fourth time, and my grandfather passed away. His funeral was 2 days within when I had my IUI. I can't imagine anything more stressful. I didn't get pregnant when I was relaxed, and I did get pregnant when I was stressed. Now, I know that I am not representative of the entire female population, but I truly believe that those that feed the idea of "just relax and it will happen" into our heads, have never gone through infertility. With that being said, I am sure that about 10 people will come after me and state how they ttc for 3 years and relaxed and it happened for them.
Any doctor will tell you that for us, it's age more than anything that is a contributing factor.