https://boards.hellobee.com/ Pregnancy, Baby and Parenting blog, by Hellobee en Mon, 13 Apr 2026 07:05:07 +0000 https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1746574 Tue, 08 Jul 2014 20:26:31 +0000 Grace 1746574@https://boards.hellobee.com/ <p>I fought for the ovulation date. I ovulated 2 weeks late and told the doctor I was not going to have messed up test results or be treated as overdue because they thought I was 2 weeks farther ahead than I was. I won. And as it was, we couldn't find the heartrate early, so I had a dating ultrasound. My date was right. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1746463 Tue, 08 Jul 2014 19:38:34 +0000 Tanjowen 1746463@https://boards.hellobee.com/ <p>@bluestriped bee: Ok, I'm one of those people that don't track, and they went off my LMP, but they told me each visit that it could be off up to 2 weeks either way on the date due to me not knowing when I ovulated. Do most doctors not take that into account? Or is the 2 week thing not even true... </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1746335 Tue, 08 Jul 2014 18:44:17 +0000 oliviaoblivia 1746335@https://boards.hellobee.com/ <p>My OB used my O date to calculate due date. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1746300 Tue, 08 Jul 2014 18:25:17 +0000 Mrs.Panda 1746300@https://boards.hellobee.com/ <p>@bluestriped bee: as people have said already, many women don't know when they O so it's just a starting point. They should change your EDD after the dating ultrasound anyway so it's no biggie :) </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1746296 Tue, 08 Jul 2014 18:22:39 +0000 Arden 1746296@https://boards.hellobee.com/ <p>Yeaaah, this is one of the reasons I prefer midwives. :P They listened to everything I said and based my due date off of my ovulation. They ask everyone detailed questions about their cycles before setting an EDD.</p> <p>If someone has average length cycles and doesn't know their O date, fine. But it shouldn't just be an automatic thing for everyone.</p> <p>I HATE the one size fits all approach to medical care. :/ </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1746253 Tue, 08 Jul 2014 18:03:43 +0000 Anya 1746253@https://boards.hellobee.com/ <p>@Snowdrop: I counted out 14 days before O and said that was my LMP (even though it wasn't) because I knew that would be the first question haha </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1745669 Tue, 08 Jul 2014 13:50:47 +0000 BSB 1745669@https://boards.hellobee.com/ <p>@Snowdrop: Good idea! I'll need to remember that! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1745664 Tue, 08 Jul 2014 13:46:38 +0000 KT326 1745664@https://boards.hellobee.com/ <p>@swedishfish: That is really frustrating! I agree that the office should go with the RE's date. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are/page/2#post-1745646 Tue, 08 Jul 2014 13:35:59 +0000 swedishfish 1745646@https://boards.hellobee.com/ <p>@KT326: I also argued with medical office staff with my first pregnancy - not my regular OB's office though - I have to go to the hospital's practice for the NT scan and fetal echocardiogram. I knew my exact due date because I did IVF and the secretary could not understand that. I just called that particular office to schedule my NT scan for this pregnancy and it was like they'd never heard of anyone going through a FET. Goodness gracious.</p> <p>I think if you've been through an IUI, IVF, or FET then the office should go with your RE's due date. It's more exact for all of the upcoming tests you might need done. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745575 Tue, 08 Jul 2014 13:08:18 +0000 Mrs. Detour 1745575@https://boards.hellobee.com/ <p>My hospital has been dismissive of my charts and OPKs even though they show that I O'd about a week late. Next time (if we're lucky enough to get pregnant again), I'm just going to lie about my LMP. It's so stressful to constantly hear that I am measuring behind and to have tests schedule too early only to have to repeat them. Cynically, it feels like a way to bilk cash from my insurance company. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745560 Tue, 08 Jul 2014 13:02:08 +0000 birdofafeather 1745560@https://boards.hellobee.com/ <p>@pinkb: same thing happened to me because I O'd on CD42! so yeah, i was about 3 weeks behind where my LMP placed me. i was very sure of my O date and insistent that they were wrong, so they did a blood test and everything was obviously okay. the dating U/S they did (again) at (my real) 7w appt gave the same exact due date I calculated based on my O date. so yeah. i am totally down with charting! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745554 Tue, 08 Jul 2014 12:59:11 +0000 danda 1745554@https://boards.hellobee.com/ <p>This is one reason out of several that I intend to use a midwife rather than OB for any future pregnancies, assuming low risk pregnancy. I found it infuriating that the OB refused to listen to me when the date based on LMP was 10 days off. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745542 Tue, 08 Jul 2014 12:52:50 +0000 dagret 1745542@https://boards.hellobee.com/ <p>@MamaMoose: I agree, HB is def. more hands on...literally and figuratively...than the general population re: ovulation. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745518 Tue, 08 Jul 2014 12:44:18 +0000 Mrs. Confetti 1745518@https://boards.hellobee.com/ <p>I would say every practitioner is different. I have weird long cycles and they took my word (which was verified by dating us) of my opk verified O date. Granted I see a midwives group - maybe that makes a difference </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745509 Tue, 08 Jul 2014 12:41:28 +0000 mrsjyw 1745509@https://boards.hellobee.com/ <p>My OB didn't go based on my LMP because I knew I was a long cycler/late o'er! We had a dating u/s transvaginally at 6.5 weeks that put me right where I thought I was! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745507 Tue, 08 Jul 2014 12:39:38 +0000 Adira 1745507@https://boards.hellobee.com/ <p>I'm surprised at how many of your doctors just ignored you! I see a midwife and I didn't tell her my ovulation date, but I told her that I had long cycles, so she scheduled a dating u/s to figure out how far along I was! She said we couldn't just go based on my LMP because it's important to do things like the NT scan in the correct window! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745499 Tue, 08 Jul 2014 12:36:03 +0000 Radish 1745499@https://boards.hellobee.com/ <p>My doctor says dates are a very big deal because that determines when they can do what. LMP is typically the most certain date, so they go with that. If you measure more than a week off of that at your dating ultrasound she is required to change it.</p> <p>For this pregnancy I ovulated around cycle day 22, so when she did the dating ultrasound and saw I was measuring 9 days less than due date based on LMP she said she had to change the due date. With my first I ovulated around CD 17 and it stayed on my LMP due date. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745491 Tue, 08 Jul 2014 12:33:22 +0000 Snowdrop 1745491@https://boards.hellobee.com/ <p>I just lied and said I didn't know my LMP but knew the date of O. They had no choice other than to go by my date! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745483 Tue, 08 Jul 2014 12:31:15 +0000 T.H.O.U. 1745483@https://boards.hellobee.com/ <p>I wish they did more of LMP + cycle length to help determine it. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745478 Tue, 08 Jul 2014 12:29:17 +0000 KT326 1745478@https://boards.hellobee.com/ <p>I argued with the nurse who made my appointment because she wanted my LMP. I told her I had a medicated IUI cycle that was long, I knew when I ovulated but she wouldn't listen to me. Luckily my doctors nurse did and she just ended up writing both dates down. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745477 Tue, 08 Jul 2014 12:29:07 +0000 MrsScottish 1745477@https://boards.hellobee.com/ <p>yeah I had this debate with my GP and OB. I know when I ovulated, giving me a date of Oct 31st, (my cycles are normally 25-26 days so shorter) and my GP used the spiny dial and gave me a date of Nov. 4th, OB refused to even listen to me, said that she does this all day every day, my due date is Nov. 6. Thats a whole week difference! I know I ovulated on day 8 of my cycle (usually day 10 but I o`d early) she said that was not possible. I just shut up at this point and smiled and nodded. Baby will come with baby comes. She asked me if a agree at the end, I said no, but really all the date does is give a date that that you wont let me go past (2 weeks after) she kind of looked taken back by that comment, but then said, you are right the date means nothing.<br /> When I went home, I looked at a calendar and if I went by her date I was like 3 days preggers when I tested positive on a normal cheepie and a First Response!<br /> Ultrasound gave a date of Nov. 2nd. So whatever, baby will come when baby comes, its a week difference not a big deal in the end. I couldn`t image women who have long cycles or unsure and it is more then a week difference! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745434 Tue, 08 Jul 2014 12:13:33 +0000 Mrs tartan 1745434@https://boards.hellobee.com/ <p>They only use your lmp to give a guess about when you should be due your ultrasound scan. If baby was measuring different from what they were expecting, they change your due date.<br /> That's my experience anyway, my Edd was confirmed after the scan, it's all just estimated anyway. 37 weeks is full term but you could go to 42. 5 weeks is a pretty large time scale to have a guess somewhere in the middle baby will come. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745426 Tue, 08 Jul 2014 12:11:50 +0000 Greentea 1745426@https://boards.hellobee.com/ <p>It is just an old school thing. For me it would be totally inaccurate. However, conception date would be inaccurate as well (for me at least). Things can take awhile in there (very scientific!). My doc does a dating ultrasound. I delivered exactly on her date! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745425 Tue, 08 Jul 2014 12:11:22 +0000 hellocupcake 1745425@https://boards.hellobee.com/ <p>@MamaMoose: this. :)</p> <p>We didn't have unplanned pregnancies but we definitely never had to reach the point of charting or temping. I had a basic idea of when I ovulated only because I'm on boards like this one, otherwise I would have never known you ovulate more or less half way into a cycle. Seriously, not stuff I ever looked up or was taught. I also know that with this pregnancy I ovulated late because I got my bfp late and was measuring almost a week behind...doctor said I probaby just ovulated later than usual (thanks to BFing). I also think going off LMP isn't that bad since most doctors don't suggest induction until after the 41 week mark, leaving room for error on conception date. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745416 Tue, 08 Jul 2014 12:03:27 +0000 yerpie110 1745416@https://boards.hellobee.com/ <p>I knew the exact date I conceived as we had unprotected sex once and that was it. My dr still went by my LMP until the dating ultrasound. It irritated me so much! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745392 Tue, 08 Jul 2014 11:48:28 +0000 JoyfulKiwi 1745392@https://boards.hellobee.com/ <p>I totally get using the last period for dating when you don't know your ovulation date and have typical cycles, but I'm so surprised by doctors that ignore everyone who charted/had a history of long cycles! I had a 45 day cycle when I got pregnant and had been charting, so I knew how far along I was. They scheduled me for my "8 week" visit but I was only 5 weeks. At first my midwife was like, "Yeah sure" but when she did an quick ultrasound check she knew right away I was right! I got a dating ultrasound and was one day off my original prediction. How traumatizing to have a doctor be such a self-important a-hole and tell someone they are miscarrying!!! </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745373 Tue, 08 Jul 2014 11:39:26 +0000 NeekieRose 1745373@https://boards.hellobee.com/ <p>I used an OPK so I knew when ovulation was and that it was about a week later than it would have been based on my LMP. The midwives I saw do a dating u/s if the suspected ovulation date is 5 or more days off. So they did a dating u/s and switched the due date. It really wasn't a big deal at all. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745369 Tue, 08 Jul 2014 11:38:09 +0000 swurlygurl 1745369@https://boards.hellobee.com/ <p>I think it's crazy for your Dr to not listen when your KNOW conception date. With both of my girls I knew conception date (well, within a day or two) because they were months with practically no activity, so there was literally ONE option. I told my Dr LMP and that date, and she has made my due date based on LMP both times. For L I just kept my own calculated due date in my mind (1 week earlier than Dr's due date) and what do you know, she was born on MY due date! My calculated due date for sister is again 1 week earlier than the Dr's, so we'll see who's closer this time :) </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745339 Tue, 08 Jul 2014 11:24:44 +0000 MamaMoose 1745339@https://boards.hellobee.com/ <p>I think HB gives an unrealistic picture of what TTC/getting pregnant looks like for the majority of pregnant women. Close to 50% of pregnancies in the US are unplanned, those women obviously were not tracking conception. And even women who are TTC most aren't charting or using OPKs, they are just having regular unprotected sex. But most women do track their periods so it's just more reliable information in the majority of cases. </p> https://boards.hellobee.com/topic/explain-to-me-why-they-go-off-lmp-when-determining-how-far-along-you-are#post-1745312 Tue, 08 Jul 2014 11:14:14 +0000 spaniellove 1745312@https://boards.hellobee.com/ <p>@bluestriped bee: I had crazy monitoring on top of my treatments so even with a trigger shot they were careful to pinpoint exactly when I ovulated and even did an ultrasound the next day to confirm that it had happened because they had so many patients who had all the signs but never released the egg. Despite being 100% sure, the MFM and OB insisted on going by my LMP due date. I stopped arguing after several months because it got confusing with the ultrasounds and I didn't want a Friday the 13th due date anymore. </p>