Due date confusion - suggestions?

[Calm]

DH usually keeps a record of my cycles in his diary. He misplaced his diary the entire month I became pregnant, so I don't know my LMP date. We guessed the 3rd of July.

To add to that, this baby REALLY wanted to be here. For many reasons but the one I'll share is that my ovulation came much earlier in July. I have been on Fertility Friend, as a birth control method, I have not been trying to conceive. For years, my cycle is 30 days, give or take, around the full moon AF. I ovulate later in the cycle, about 17 days after AF. To catch us off guard, I ovulated early in my cycle in July, about 10 days after AF but I'm not entirely sure of the date. I just remember thinking, oh s***, I just ovulated, which means that the other night.... yeah.

Sooo, all the due date calculators tell me a date based on a 14 day luteal phase, and no calculator seems to take into account a one off weird cyclic mishap that is not standard for your body. Even though they say "you know your body better than an ultrasound can show etc, so it's more accurate to base it on your cycles". I know they go on LMP, but that is always based on a 14 day luteal phase. The dates change significantly with a different length luteal phase.

So do I calculate how pregnant I am by my usual ovulation - or do I calculate the entire pregnancy on that one-off one? Which hormonal cycle will my body be on during pregnancy?

[Patchfire]

If I were you, I would count back two weeks from your day of ovulation, and say that was your "LMP" date, since most due date calculators use that. Going with your guessed dates, then, of July 3rd and about ten days later, you'd put in June 29 or so as your LMP. So early April. :)

[Jes'sBeth]

if you know ovulation date, go with that minus 14 days for your LMP. We know ovulation because of ultrasound cycle monitoring and just gave our midwife our ovulation date since it's way more precise than LMP. She then counted back 14 days to get LMP to plug into her calculator.

[Jujubie]

If you can guess your O date, this calc can give you a due date based on your O date. Congrats. :)

http://ivf.ca/calcu.htm

[Calm]

Thanks! Although, I don't know the O date either, otherwise I'd be all set. I have no dates. All I know for sure is that I ovulated much earlier. So I'm not sure whether to attempt a count based on a guess for the one off or for my usual cycle. I'll have a hard think about it today and see if I can nail a date for one of the things.