Do you use your FF due date or base it off LMP?

[Deleted User] · February 2012

According to FF, my due date is October 10th, based off ovulation. I know I ovulated "late" (according to the "norm" or "average" 28 day cycle) on CD 21. If I base the due date off of my LMP, it's October 4th. That's almost a week off!

So my question to you lovely ladies who charted with FF is which date would you consider your "true" due date? Obviously I know when I see my OB we will be able to clarify it more, but I'm curious.

badtzmaru22 · February 2012

O date, all the way. I o'd on CD40-something, so there's no way LMP is accurate for me. Some docs will do an early u/s to help date the pregnancy, and those are usually pretty accurate. I was seeing an RE, so I had u/s starting at 5 weeks, and those always measured in line with my O date. Even if you don't get an early u/s, I would go with O date.

damabo80 · February 2012

O date, since I Oed a good two weeks late.

My re will confirm it next week when I have my first ultrasound.

Mrs.KLF · February 2012

O date for sure. If I used my LMP, I'd be nearly two weeks further than I actually am.

Tash13 · February 2012

O date. I have a very regular 30 day cycle but most LMP charts are for 28 days so it's always a little off for me. I was also strictly charting and my first u/s came back measuring 5 days behind so I don't necessarily think that's 100% either, but a 5 day difference doesn't make that big of a deal to me so I let them put whatever they wanted on the chart.

[Deleted User] · February 2012

Damn lol, I guess that means I'm 4w0d instead of 4w6d!

Oh well, I'd rather be accurate.

ArchyFlores · February 2012

O date, definitely. I know I O'ed late this time by a couple of days. Even though, like Sweet Turnip said, I gain a few days.

biddy53178 · February 2012

Myself and my RE went by my O date as I was charting, but my OB has always one by my LMP- no real difference tho- the date I have on here for my ticker change etc is my O date EDD but my OB has it for three days prior- which at the end of this pregnancy I'm ok with

Eveanyn · February 2012

MrsNorry:

Damn lol, I guess that means I'm 4w0d instead of 4w6d!

Oh well, I'd rather be accurate.

If that's the case, then our EDDs are 1 day apart!!

My LMP vs. O date would be only kind of off since I Od on CD 12, but if you know your O date, go off that. They use LMP assuming that everyone Os on CD 14.

nikkks84 · February 2012

well for me FF showed i Oed a week late so i based my due date on that ..but at my 9week{according to lmp] i was measuring exactly 9 weeks instead of 8 like FF predicted...so my ob has used my lmp to calculate the due date...so i guess u will know for sure at your 8 or 9 week u/s

tiffanysbride · February 2012

Neither I used my first u/s and so will your OB.

walkerb4 · February 2012

I used my O D to adjust my LMP slighty to match. I O'd at CD 17 or so, so not too far off that cycle!

csquared426 · February 2012

O date. For me it's only a few days difference, but I still use the O date. My OB is going by my LMP though.

Zilly13 · February 2012

LMP. Even though I was charting and knew I O'd late my OB dated me based on my LMP. At my first u/s, LO was measuring up perfectly with my LMP vs my O date.

Babymamawithdrama · February 2012

In my head I keep my o date.... My ultrasounds appear to more closely date our pregnancy to the o date rather than LMP, they hesitate to change it earlier because then a red flag is alerted when you pass your "due date" triggering indiction. I did however put my ticker by the Dr.'s (LMP) date, and when (non medical) people ask I usually go by my o date. Dr has been talking for the past month of moving it up and I go for an u/s next week so I guess we will see then.

luvinlifeMN · February 2012

I'd go off of O date...but my dr. always goes off LMP. I know some friends who O'd late gave doctor a different LMP date so their due dates would be more accurate. They did not want to hear how the baby was measuring small all the time. Congrats!

cutebride73 · February 2012

OB's are generally clueless about anything other than going by LMP - they don't always care or believe you when you say you ovulated later (or earlier). Since I used an IUI to conceive and it was a medicated cycle with a trigger shot I know exactly when I O'd. I am lucky that since I will have 2 u/s's with the RE they will date my pregnancy and tell my OB when I am due. Although, I am sure when I go to the OB, they (or a nurse), will still ask my LMP and tell me my due date is otherwise - lol.

For now, I am going by when I know I O'd and had my IUI, once I have my u/s the date may be adjusted by a day or two depending on how I measure. If I was in your position though, I would take my charts and try to convince them to go by that instead since that is what is accurate.

This could be important if you are having the NT scan because it should be done at a certain time and if your OB thinks you are a week ahead of what you are then that could affect things. Good luck!!!

juliane2004 · February 2012

badtzmaru22:
O date, all the way. I o'd on CD40-something, so there's no way LMP is accurate for me. Some docs will do an early u/s to help date the pregnancy, and those are usually pretty accurate. I was seeing an RE, so I had u/s starting at 5 weeks, and those always measured in line with my O date. Even if you don't get an early u/s, I would go with O date.

This. I'm not sure why you WOULDN't use your O date.

[Deleted User] · February 2012

Thanks for your responses.

I know that my OB will probably try to go by my LMP until I have a dating u/s, I was just curious to see if anyone actually used LMP to base their EDD off of, or if everyone uses their O date. I know that nothing is set in stone.

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Do you use your FF due date or base it off LMP?

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