for bubs 1 @ 8 and a half weeks, I used the date of death, as the d&c was done the same day. Bubs 2 was a chem preg so I used the day I got af. Bubs 3 was harder...it was 7 weeks since my lmp, but I had been testing for a long time and hadn't gotten a BFP, so I thought I must have O'ed a week or so later than I thought. I used the day of death again. Hth