If I know my ovulation date does this change the EDD?

[ducksandacorns]

Ok so I know nothing is taken as exact until the dating scan (and even then it can change) but I was just wondering if you know your ovulation date, and if that date is earlier than 14 days pre next period, would you be dated as a few days further along?

My LMP was 28.03.19 which makes me 5+3

I ovulated on 08.04.19 Does this date make me 5+6?

I know it makes no difference really, just wondering how due date is calculated from ovulation.

I think so. Based on my lmp I've 4 weeks, based on my actual ovulation date I'm 3. Not evenness cycle are typical but it's say 5+6

Thanks @SleepingStandingUp

Your EDD will be calculated by your 12 week scan.

The midwife will date you from the start of your last period regardless of if you know your ovulation date. You will be given an official due date from the measurements of the 12 week scan.

Thanks both.

Yes I know the EDD will be given at the scan, just wondered if I could count from ovulation for the time being.

I didn't word the title very well!

No as others have said it’ll be last period then measurements at the 12 weeks scan. It’s not important for enough to do special calculations tbf

(For the midwife to do special calculations not you!)

Kind of. It really depends on when implantation took place. The EDD calculators assume ovulation at day 14 and implantation at day 21. If you know you implanted earlier or later than day 21, you can change your EDD in your head but you will be given a date depending on the size of the fetid at your 12 week scan. This is why EDD can change even if people are sure of their ovulation date, as it's much harder to be sure of the implantation date and it can be anywhere between about 5 and 12 days post ovulation.

Fetid?! That should be fetus 😂

I didn't realise it's possible to be 100% certain of exact ovulation dates. I think there's always a slight margin for error even if only a day or 2 but I may be wrong. Congratulations on your pregnancy.

My hospital due date is 2 days before I know I ovulated but as its only 2 days I dont think it makes much difference! I tell people my hospital due date but in my head and on the apps i use my own due date.

It doesn’t really matter though, because 40 weeks is only an average pregnancy length anyway. The 12 week scan is absolutely the best indication as to whether your baby is ahead of behind average in early pregnancy but obviously, considering how few babies come on their EDD that’s still a very inaccurate science!

Well I'm counting from ovulation as that's what Natural Cycles is telling me (it also claims that it's more accurate than scans as well as LMP) but the midwife wasn't interested and jotted down LMP after looking surprised that I didn't know what it was without double checking the app (if LMP was accurate then I got my BFP on 'dpo 7'). Anyway I'm expecting some form of correction at the scan.

Interestingly the dating scan isn't as accurate as they claim either - I found a research paper about this the other day - the calculations they use are based on them 'dating' the measurements to an expected size of foetus if the woman had ovulated on day 14 (the study itself found that even women with a 28 day cycle didn't on average ovulate until day 17 I think).

I know as others have said, there is no certainty that a baby will be born on it's EDD, but they do use it to instruct various care pathways nearer the time and that's the part that concerns me.

Just say no to induction weathergirl. They still won’t be interested in your ovulation date but can’t make you be induced

passthecherrycoke I fully intend to - but have anxiety around medical stuff & not being listened to by medical staff (prior experience not helping).

I ovulate on day 23 of a 32 day cycle - so I'm exactly a week out from my LMP date - my first scan was booked based on LMP so was exactly 11 weeks and went back 2 weeks later and was 13 weeks which was exactly what I should have been based on ovulation - midwife only went by LMP though even though I knew my first scan date would be too early!

So yes you can definitely count in your head differently and then see how accurate you are at the 12 week scan but medically no-one else will worry about it! I think it's useful to know though because I had some early bleeding and an early scan and knowing I was a week out meant I wasn't anxious about why the baby was a week smaller if that makes sense.

Midwife dated me five days later than my 12 week scan, I knew I had shorter cycles but it doesn't really matter as the % of babies arriving on each day in the term period is pretty small.
I get what you're saying about it from an interest point of view though, I was quite irrationally pleased when the scan agreed with me 😂

My previous pregnancies, I was dated at the 12 week scan to be a week or so ahead of the date given to me based on my lmp, this time at the 12 week scan, I was a day ahead of the date given to me based on my lmp and over a week ahead of the date I was given at an early scan in the early pregnancy unit a few weeks before that. They'll take the dating scan at 12 Weeks as the official date regardless of your own knowledge of ovulation, the explanation I was given at the early scan I was given being so out from my own calculation based on my dates was that I likely ovulated later than I thought, that theory was squashed though when the 12 week scan put me back to what I thought. For the sake of a few days as you say though I'd not worry about it. X

My cycles were so long I had my "12!" scan at 7 weeks because I ovulated do far after my lmp. Nice early peek though

Apparently only 4% of babies are born on their due date, and in France a pregnancy is counted as41 weeks not 40. So it’s all academic.

Congratulations op

Thank you everyone for your replies.

I think the main reason I asked is due to anxiety - I had a MMC in January and want to get to 7 weeks as soon as possible. But pretty sure as soon as I've got to that milestone, I will just become anxious until the next!

@ducksandacorns totally understandable. Are they giving you an early scan? I've a few friends who have been through similar and they feel the same, every milestone brings relief but a new one to focus on and they try not to let themselves get too excited but they all say that getting passed the point they got with their previous losses is always a big one and it does bring some relief. Waiting game is tough. I'm 32 weeks this week and where I think it's gone fairly quickly it's now feeling like there's forever to go. Here's to the next 7/8 weeks flying by as quickly as possible ❤️