Date of LMP

[AliSxo]

Hi, so I went for a private scan and I'm 8+5, if I went by the date of my LMP I'd be 7+6. I'm confused how I can be so far ahead when 8 weeks and 5 days ago I was still on my period? Does anyone else get confused by this? Xx

Congratulations!
Scan dating basically assumes your LMP was exactly 2 weeks before conception, which is obviously not always the case. So your baby, when dated at 8+5, is actually 6+5 weeks post conception. Possibly you ovulated earlier than you thought? Eg CD 8 or 9? Also scan measurements can be +/- a few days either way.
Sometimes it’s just a mystery :)

I ovulated around cd12 and I was tracking it with OPKS, it's the difference of a few days so I'm not worried but I was slightly confused! Thanks for replying xx

Working out on a calculator on a 24 day cycle which is what I'd of had with ovulating on CD12 I'd be 8+3 so measuring two days ahead of that xx

Hi. I'm new to mumsnet and not sure if this is the right thread. I've got a burning question that's driving me nuts, about when we conceived. I am 13+5 weeks pregnant. Can anyone help me before I let off my speil haha? Thank you xx

@Sally160586 we can try but you’re usually better to start your own thread, will get more replies that way

@Sally160586 hi I'm sure there are online calculators you can use, if you know when you DTD and how many weeks/days you are you might be able to work it out? Xx

Ok I'll start my own thread if this fails. Just want to ask advice about when I conceived. I'm currently 13+5. My lh surge was on day 17, so I'm guessing I ovulated day 18 or 19. We dtd on day 17 and 18, but also on day 13. My cycle is about 31 to 32 days, little bit inconsistent after having my daughter in jan 2019. My scan on the 28th april showed I was 12 weeks exactly pregnant.

Ovulation 18 Feb or thereabouts.

@TenThousandSpoons0 so theres not much chance that I got pregnant from dtd on day 13? Thanks for humouring me. Just on day 17/18 we were in a specific place and if we conceived there it would be quite special. Thanks x

@Sally160586 you haven’t told us any actual dates so I don’t know what day 13 means in terms of actual dates. If you ovulated about the 18th feb then you could have got pregnant from sex any time between 13 feb and 19 feb (5 days before to 1 day after ovulation). But it’s not exact.

@TenThousandSpoons0 Sorry if I'm not making sense. My lh surge was the 18th feb, so this was 17 days into my cycle, so I'm assuming I ovulated the day after on day 18 in to my cycle. First day of my last period was 2nd feb. My question really is it it likely we conceived on the 13th, or the two days that were bang on ovulation time?

See above, both possible. Much more likely the days right on ovulation time tho

Thank you. I know there's no exact science. Just I read sometimes that your window is 3 days before ovulation, 7 days, 5 days, I've even read 2 days. it would be nice if it was exact. Im a massive overthinker and being in lockdown has sent my thoughts wild. I do think we conceived near to ovulation like you say much more likely but equally possible earlier too. Thank you for your help x

@Sally160586 the first day of my lmp was 1st Feb. I had ovulation bleeding (I think) on the 15th. Dtd once only that cycle on the 14th and am now 14+3 (from dating scan). You’re most likely to have conceived from dtd on 17th/18th as i think the surge detects when you are about to ovulate making ovulation 18th/19th. The 13th is possible but unlikely.
@AliSxo it’s possible you either ovulated earlier or implanted earlier. Implantation can happen between 7 and 14 days so a large window. Also the babies are so tiny at that stage that a mm or so either way can change the date significantly.

Thanks @ACatCalledLola how mad that the first days of our last period were a day apart and I'm nearly a week behind you. I always had the lh surge on day 16 before having my daughter in jan 2019? it took a while to get pregnant and I only tracked it once this time.