I had long-cycles (35 days) when I got pg with DS1, and I knew exactly when we had conceived (I wasn't charting, but DH was on tour with his band for three weeks, and I was a little excited that he was home, so it wasn't hard to figure out
), all of which influenced me to believe that baby day would be considerably farther away than my LMP EDD, and maybe even my u/s-based EDD. He ended up coming four days later than my LMP EDD, and two days earlier than my u/s-based EDD.
With DS2, I had weird looong cycles (AF came back at 13 months, and I had like three periods), one that was 60 days, we *think* that we conceived about 3-3.5 weeks later (this time, I was the one out of town for ten days, visiting family, and it either happened before or after that trip, but we were never really sure, lol)...he also came four days after my LMP EDD.
This time, I'm really interested to see what happens. I had a miscarriage in May, and we conceived right away, before I had a period, so my m/c date is my "LMP" date. It's hard to know when I ovulated, but since that has proven to not make me do that
much later in the past, it will be interesting to see how much it matters this time.
So, all of that to say, that IME, you just have a certain baking time, and ovulation doesn't really play that
big of a determining role. I do believe that everyone has a different gestational time, somewhere between 38 and 42 weeks, give or take.