Question about calculating due date

[mommy2bnc]

For those of you that know you ovulated later than CD 14, do your doctors (and you) still base your EDD on the first day of your last menstrual cycle, no matter when you O'd?

For instance, the nurse said that I am 5 weeks pregnant right now, but I know that I ovulated on CD 21, so I have been calculating based on a 35 day cycle (vs. 28 day cycle) so I see that I am only 4 weeks pregnant. She didn't seem to care which day I actually ovulated.

Just wondering which calculation I should go by?

[theboysmama]

day of ovulation if you know it

[AutumnMama]

Yeah, I've noticed that a lot of medical people don't care what day you "think" you ovulated (they usually don't believe you IME), so what I would do, and have done, is count back 14 days from the day I know I O'd and use that as my first cycle day.

So in March AF showed up on the 3rd, but I don't ovulate till day 18, so I'm using March 7th as my 'official' CD1.

[mommy2bnc]

Good idea AutumnMom, wish I would have thought of that. Unfortunately the date of my LMP is now already in my records. Hopefully DH will agree to a homebirth anyway so I won't have to worry about that, and can explain to the midwife. Thanks!

[terrainthailand]

My doctor did the same thing - didn't much care when I claimed to have ovulated just went on LMP which was about a week 1/2 off. Fortunately when I had an ultrasound at 6 weeks she agreed to change the EDD based on the measurements so that put my EDD right around when I thought I should be based on my suspected ovulation time. How annoying though.

[chic2chic]

i O'd early, on CD12 -- and brought my chart along to my appointment to prove it -- but the midwife wisely suggested we use my LMP date.

that will give me a few extra days in case i go past my due date. which is a good idea since i will stress less about going a few days "late" (which happened with my last pregnancy).

it's OK to "fudge the data" occasionally -- obviously health professionals do it all the time. so those of you who O'd "late": perhaps one idea is to give a slightly later LMP date instead? it's shocking how many doctors/midwives still insist that all women ovulate on CD14

[sapphire_chan]

You've just now told them LMP? (Congratulations!) I'd recommend "I'm so sorry, did I say the 12th for LMP? That should've been the 19th."

[mommy2bnc]

sapphire chan-Great idea, I might try that at my first prenatal appointment next week!

[erinmacey]

If they ask, I'm tempted to tell the truth. My last visit from AF was in early January.

That would put me at...what, the beginning of my second trimester? Wow - I've gained so little weight!

[Funny Face]

Originally Posted by AutumnMama

... what I would do, and have done, is count back 14 days from the day I know I O'd and use that as my first cycle day.

:
Thats what I did. When I talked to my midwife she said "So what due date did you give yourself?" She knows I have wacky cycles.

[A Mothers Love]

Originally Posted by AutumnMama

Yeah, I've noticed that a lot of medical people don't care what day you "think" you ovulated (they usually don't believe you IME), so what I would do, and have done, is count back 14 days from the day I know I O'd and use that as my first cycle day.

So in March AF showed up on the 3rd, but I don't ovulate till day 18, so I'm using March 7th as my 'official' CD1.

Oh great!! I "O" way late & was wondering what I was going to do/say about that. Thanks

[rstump]

I always know the conception date....since I chart.

So I go by conception date. I figure out what that "should be" for LMP just to be able to give to "health professionals" so they can FEEL like they have the correct info.

[superlori]

These are good suggestions. I've printed out my chart from fertilityfriend.com to bring along (I o'd on CD20 and have a 35 day cycle), but maybe I'll just do the fake LMP date. That sounds more promising.

No matter what, I'm insisting that they use MY date. With dd, I had placenta praevia, and when I started heavily bleeding (a sign it's time to DO SOMETHING), the doctor wouldn't section me because according to THEIR dates, I was 2.5 weeks early. According to MY dates, I was only 1.5 weeks early. They made me wait days before sectioning me, and even then it was only because I totally lost it and sobbed and sobbed to the midwife about how I was losing my baby and I just know if we wait it will die. Thankfully, my midwife passed that on and I was sectioned an hour later!

So not going through that again.

[korintherin]

I went in with chart and said "you can have the date of LMP, but I'm pretty sure that's going to confuse the issue, because I didn't ovulate until day 22-23 and we weren't having sex back around day 14!"

I think they believed me

[A Mothers Love]

Originally Posted by korintherin

I went in with chart and said "you can have the date of LMP, but I'm pretty sure that's going to confuse the issue, because I didn't ovulate until day 22-23 and we weren't having sex back around day 14!"

I think they believed me

Your'e lucky they believe you. I thought about lying to my MW cause I "O" late too. I thought I'd just tell her the truth since she is a MW & she would go w/ what I say. Nope. she is going by LMP. I am waiting for my 1st u/s or whatever to prove me right

[RoadWorkAhead]

My MW goes with date of voulation since its a 42 week window for delivery (past 42 they have to release you by state mandates) so this gives me the longest window by going by the latest possible O date. I'm in no hurry....Last one came 8 days past DDs

[Quate]

I was wondering, does implantation date play a role in this at all? Or doesn't implantation matter for development? (Beyond, of course, the fact that it has to happen sometime.) Because there can be a fairly large range there too, I think.

[caedmyn]

Originally Posted by A Mothers Love

Your'e lucky they believe you. I thought about lying to my MW cause I "O" late too. I thought I'd just tell her the truth since she is a MW & she would go w/ what I say. Nope. she is going by LMP. I am waiting for my 1st u/s or whatever to prove me right

Just FYI...it's only very early ultrasounds that are accurate for dating purposes. The standard 20 week ultrasounds are not accurate. Not sure if you knew that or were planning on having an early ultrasound.

[caedmyn]

Originally Posted by Quate

I was wondering, does implantation date play a role in this at all? Or doesn't implantation matter for development? (Beyond, of course, the fact that it has to happen sometime.) Because there can be a fairly large range there too, I think.

From what I've read they generally say implantation happens 7-10 days after O, so it's really not a very big range. Besides, the chances of knowing when the baby actually implanted is very slim, so I don't think you could base anything off that, anyway, even if you thought you knew when it happened.

[A Mothers Love]

Originally Posted by caedmyn

Just FYI...it's only very early ultrasounds that are accurate for dating purposes. The standard 20 week ultrasounds are not accurate. Not sure if you knew that or were planning on having an early ultrasound.

yes, Iv'e heard that. I have no clue what/when she plans to do anything if at all.
If at any point she says "you are measuring a week behind" or something to that effect, I will then remind her that I am not as far along as she says. I hope at some point she will just listen to me