I think there's a lot to be said about dreams! If you're dreaming about it, it could be!
Funny story - We knew both times about 1 month before. I was at a birthday party and one of the other attendees is a psychic. She came up to me and said, "are you trying to have a baby, because I see it happening for you in May." Freaky! We hadn't told anyone we had been trying, so it's not like she could have heard it through the grapevine. I was so excited to take the test that month, because the last few had been negative, and getting pregnant then would put my due date in May. Took the test...negative. I was devastated. Several days later, I still hadn't gotten my period, so I took another test and it was positive! Due on May 13th!
A couple years later, I bumped into that woman at a store. She asked me if I had any other kids. When I said no, she glanced at my stomach, raised an eyebrow, and said "okay" (in a way that said "I know something you don't know!). DH and I weren't trying then, so I kind of dismissed it. Well, a couple weeks later, I found out I was pregnant!
The day before our first OB visit with the 2nd pregnancy, I had a dream that I was feeding the baby, then looked around and saw another baby - 3 kids? whoa where did that one come from?!? I told my dh about it, and he looked at me in stunned silence, then told me he just had a dream we had twins. Well, guess what we found out when we went to the dr...yup, twins!