Help with EDD please

[DearDinah]

Hello,
I know you are supposed to go off the date of your last period but since coming off the pill my periods have been very irregular for 7 months. For example the last one was 43 days, the one before 46, the one before 53!
I got a CBFM & this month got a peak on the 14th & 15th Dec, got my BFP (faint) 25th Dec & today (30th) it's a good strong second line :)
If I went off a cycle of 43 days the 25th would have been far too soon to show up wouldn't it? I've guessed at 2 weeks after peak ov day, making it a 36 day cycle, is that what you would do?
I'm seeing the doctor today but won't he just go by the book & use my last period to date it?
Sorry if that's a confusing mess, any help would be appreciated!

I would prob take date for LMP as 1st dec ie 14 days before ovulation. Tbh it doesn't matter too much as you will get a 12 week dating scan where they can tell really accurately. It may mean that you need to return for Downs screening if dates are wildly out but can't see any other issues.

Oh and congratulations

I'd go 4 weeks before expected period.
Since you don't know that, I'd go for 2 weeks before ovulation.
Or just tell the Dr you don't know when your last period was, but beleive your 4 weeks pregnant atm.
Congratulations

Thank you, really appreciate the help, feeling pretty clueless! :)

If it helps, I too was unsure about my dates as I'd only just come off the pill. My GP sent me for a scan at 6+4.

If go with your lmp date then you will
Get an earlier scan

I lied, as i had come off the pill and had a slightly wonky cycle. I knew when i ovulated give or take a day either way so i just took two weeks off my ovulation date and told them i had a period then. When i had my scan it agreed with me to the day.

Hi and congratulations! I have PCOS and my cycles are 47 days, so I was in a similar boat as you. When you see the midwife for booking in appointment she will probably calculate your EDD by the 'standard' 2 weeks after your last period (my original due date was Boxing Day) but then when you have your dating scan they'll be able to get a much more accurate date (mine moved to 11th Jan, so quite a difference!)

If you want to calculate it now I'd go with 2 weeks before peak ovulation day, and remember you might end up with an extra scan which I thought was a good thing (because you might be 2 weeks early for your dating scan as they can only work it out using the 'standard' at first). Hope that helps?

Thank you everyone, I used my actual LMP date & he put me at 5 Wks, due 30th Aug, scan will reveal all I guess! So excited :)

I had the opposite to you...very short cycles. Told midwife at booking in. She organised a scan, which moved my EDD forward by 9 days.

best of luck.