Short cycle - amend due date?

[aletea]

My LMP sees my due date at 19 December. However, I would have had a 22 day cycle that month. Ovulated on day 12.

If I adjust the due date calculators I get 13 December.

Given there's nearly a weeks difference is like to know which is right but I don't know if adjusting is the correct thing to do. Will the midwives adjust? I don't recall them even asking my cycle length before.

Tbh, it doesn't make any difference. Due date is +- 2 weeks anyway, so a pretty vague estimate.

Ime they won't adjust unless a dating scan shows you to be a week or more out.

My lmp has me at 18weeks, I'm 16+ just now, they're going by measurements of my scan. Helped that i could tell them to ignore my dates though.

I know they'll come when they come, but a weeks difference will mean I may have to start mat leave a week sooner than I'd like, or that I'm start having to fend off medics who want to induce sooner. My babies always have big heads so scans aren't brilliantly accurate.

Your due date will be decided on your first scan, it will go by the measurements of the baby, and LMP will pretty much go out of the window. I know the date we conceived, scan put me four days earlier than that because of her measurements

I have very irregular and long cycles but due to my POAS addiction while ttc had a fairly good idea when I could of conceived. GP and MW weren't interested, they just go by LMP until the dating scan changes it. It worked out quite well for me as it meant getting an early scan which helped with my anxiety.

My lmp was 20th December. That would put me at 18+2 but I'm 17+3. According to the 12 week scan, I was 11+3 when I had it.

I'm in the same position, the hospital and scan have me a week and a half later than what I am, it worries me too that they'll want to induce me. I've told them and all they say is that they have to go off my Lmp. Frustrating.

Changingagain, I am knew the same position as you with long cycles (although not exactly sure when I oved) and therefore hoping for a cheeky early scan too. Can I ask, how early was your scan? And did you then get another one at 12/13 weeks to check everything is okay or was it just the one? Thanks

They will only change your due date at the 12 week scan. Mine was moved back a week (which I agree with because of my longer cycles).

oneyorkshirepud hmm yorkshire puds My first scan was 12 weeks after my last period, at which I estimated I was about 8 weeks. They called me back for another 4 weeks later which was when they did the normal checks and dated me at 13 weeks, so the first would actually of been at 9.

Be warned though, as they were so insistent on going by LMP and not listening, the sonographers first reaction was, "it looks like your pregnancy has stopped progressing". Needless to say, my heart dropped and the next few minutes were awful until she could confirm (with an internal scan) that the baby had a healthy heart beat and I just wasn't as far along as she had expected.

They will go by lmp to determine scan date and then scan date to determine EDD. I have long cycles so knew I wasn't going to be 12 weeks at my scan. I told the mw and sonographer this so they were aware and didn't think the pregnancy wasn't viable and the scan dated 3 weeks earlier. I then had a repeat scan at 12 weeks.

I've had my due date moved forward by three days at the 12 week scan, they tend to go by that irrespective of what you tell them - my initial dates where based on a 28 day cycle, as again, the healthcare professionals generally decide that you know nothing and they know it all...

I wish I could remember what it we but someone I knew (who was training to be a midwife) had posted a link to an article once about how menstrual cycle length can have an impact on the length of your pregnancy. So basically, if you normally have a very long cycle (like mine, which is anywhere between 33 and 37 days normally), you're more likely to have a slightly longer pregnancy.

I'll see if I can find it, it did make for very interesting reading.

For me personally, I also know when we conceived, but even going by my LMP and looking at my cycle length I put my due date around the end of May. Midwife/scan dated it as 16th May. So... We'll see!

Ooh interesting stuff, and Yey for early/extra scans! Thanks Changingagain, I will be very sure to make clear to the sonographer that I will only be 9 weeks!

If you ovulated on day 12, your dates won't be too far out anyway as the calculations assume you ovulate on day 14.

Regardless, they will go by the date on the scan. This does make sense for many reasons. Most women don't know when they ovulated exactly, some women only know the date they had sex and this could be nearly a week before actual conception, some women will lie about conception for myriad reasons, implantation can take different amounts of time for different women, just to name a few factors. The dating scan happens at a time when the baby's growth is pretty uniform so they can fairly accurately date the pregnancy to within around 5 days either way. It makes sense to use the evidence of what's happening with the baby than taking the word of all women when yes some of them will know exactly what's happening but most won't. MNers are a self-selecting bunch. We tend to know more than most.

A good midwife should listen if you say you have very irregular or very long cycles and make an educated decision about dating your pregnancy and when to scan early for confirmation. However, when you're talking about ovulating on day 12 instead of the textbook day 14, it doesn't make much difference to wait for the dating scan.

Thanks avocado, that'd be good if you can find it.

When I refused to let them change my second EDD because they were putting me too far ahead I was threatened with the consultant. Saw the consultant and he was like...wtf are they doing wasting my time, have the date you want!

I have a short cycle (24 days, ovulate day 10) but for both pregnancies they didn't amend the due date. I was 7 days early for both, but the baby will come when it's ready!

I have short cycles, they took the edd from the 12 week scan dates, based on which I conceived on day 7 (which is probably true). I went into labour on this due date too.