Community› The Bump Month Clubs› January 2016 Moms
January 2016 Moms
New Discussion

LMP and Ultrasound not matching up..,

winters17winters17 member
in January 2016 Moms
Hi there Everyone!

Has anyone else experienced this?

I went in for an early/dating ultrasound last Thursday and based on my LMP and Dr's due date projection I was 7 weeks 3 days with a due date of January 25th. I saw, but wasn't allowed to be told much of anything from the tech, a good heartbeat and normal looking embryo. This is my second baby, but didn't have my first ultrasound with my son until 10 weeks.

Anyways, I received a happy call from the nurse at my doctors office congratulating me on my healthy 6 week and 4 day (I think she said) pregnancy. I panicked because I thought I was further along and never experienced this with my first. She said she'd speak to my Dr a d call back. When she did they were still very optimistic and assure me there wasn't cause for concern....

Has anyone else experienced this? Do you use your LMP to gauge the due date or the ultrasound? My periods have been and always are very, very regular.

Thanks in advance! ;)
Report Reply to Post

Re: LMP and Ultrasound not matching up..,

  • dana013dana013 member
    This happened to one of my best friends. She's currently 6 months, but she was about 2 weeks off in the beginning. Went in thinking she was at 10 wks based off of LMP and was only at 8. Everything else has been good and baby is healthy. I wouldn't worry too much.
    Report Reply
  • Loading the player...
  • apinkpelicanapinkpelican member
    My dr changed my due date yesterday. She said it was bc I didn't have a 28 day cycle. Even yours are regular, are they exactly 28 days or long it short? Maybe you just ovulate later than you thought. My dr told me there is nothing to worry about and I'm sure the same is true for you! Fx for a H&H pregnancy!
    Report Reply
  • willashbabywillashbaby member
    Since you're less than a week off don't be concerned. I have a normal cycle as well but I actually ovulate on day 15/16 and only have a 12 day LP. Not a perfect 14/14. Your cycle may be similar hence being slightly behind. Anything within a week is not to worry.
    Report Reply
  • babygirlm181babygirlm181 member
    Last week went to get my first U/S with baby number 2 dr thalt I was 11 weeks but u/s tech said it looks like I am only 9 weeks but told me my doctor would have the final saying on that which she told me it looks I am not 11 I am only 9 ......got scared at first during u s because they couldn't find anything while trying to look threw tummy they had to go the other way
    Report Reply
  • careermom06careermom06 member
    @winters17 I am in the exact same boat you are. By my LMP I am due January 25. I went for a dating ultrasound at 7w2d and I was measuring 5w5d. I go back today at 6w5d for another ultrasound hopefully to see the baby this time. I think it is normal that babies grow at different rates. Do you have another ultrasound scheduled? Good luck
    Report Reply
  • littlerain0littlerain0 member
    I went in to my US thinking I was at 8.5 weeks because of LMP and came out only at 6.5 weeks. There was a heartbeat and everything so it was reassuring but I was worried about it beig a development problem. They reassured me though that because I have PCOS and my ovulation is all out of whack I probably just ovulated later than estimated.
    If I could be two whole weeks off, I'm sure one week is possible and healthy.
    Report Reply
  • MamaHollandMamaHolland member
    I was off by ten days so the doctor said they go with the ultrasound. LMP would make the due date Jan 25 but since the baby was longer than it should have been at 6 weeks, the baby measured 7 weeks instead of 6 weeks, so the due date as moved to Jan 18 based of the crown to rump length in the ultrasound.
    Report Reply
  • winters17winters17 member
    Thank you everyone for your replies! What great support.

    My periods have always been pretty bang on. Maybe off by a day or two tops. Ironically I'm still breastfeeding my 15 month old son, only once a day now, but even at three months being exclusively breastfed, my period returned like clockwork! Ugh!

    I have done some research now too and feel a bit better. I guess every pregnancy is different, but never experienced this with my first so was pretty alarmed. I see my midwife tomorrow so I'll ask her and perhaps ask for another u/s. Maybe closer to 10 weeks or so?

    I think it's odd. The tech said the lady before me had exact same LMP. They had to go in vaginally for her. Thy don't for me. She could see everything. I guess I'm just worried about the development and also whether they will gauge due date of my LMP or the u/s?

    Honestly, I worried about my son from the minute there was a second pink line and still do and will every day. Motherhood!!!!
    Report Reply
  • winters17winters17 member
    I really wonder how accurate the u/s can be that early? Maybe I never had this problem with my son because I didn't go until 10 weeks!? I've heard the dates can catch up.
    Let me know how the one today is. I think I'll try and schedule another one too.
    Report Reply
  • apinkpelicanapinkpelican member
    winters17 said:

    Thank you everyone for your replies! What great support.

    My periods have always been pretty bang on. Maybe off by a day or two tops. Ironically I'm still breastfeeding my 15 month old son, only once a day now, but even at three months being exclusively breastfed, my period returned like clockwork! Ugh!

    I have done some research now too and feel a bit better. I guess every pregnancy is different, but never experienced this with my first so was pretty alarmed. I see my midwife tomorrow so I'll ask her and perhaps ask for another u/s. Maybe closer to 10 weeks or so?

    I think it's odd. The tech said the lady before me had exact same LMP. They had to go in vaginally for her. Thy don't for me. She could see everything. I guess I'm just worried about the development and also whether they will gauge due date of my LMP or the u/s?

    Honestly, I worried about my son from the minute there was a second pink line and still do and will every day. Motherhood!!!!

    For me they are going by the US, not the period. Pushed my due date back almost a week :-/

    Report Reply
  • BBEA2006BBEA2006 member
    Mine was way off, but I knew that before our u/s.  Based on LMP, I should be 10+1 weeks.  We had our u/s yesterday and measured 6+5 weeks...so yeah, off just a little.

    I have always ovulated later in my cycles and I just came off of BC so I knew I was later.

    Baby Birthday Ticker TickerBaby Birthday Ticker TickerBabyFruit Ticker
    Report Reply
  • CaraBoonieCaraBoonie member
    My periods have always been like clockwork, but then when we went to try conceiving I used an ovulation test expecting to have negatives for a full week and instead ovulated on my second test, only a week after the first day of my period! I'm not sure if this was an anamoly for the month (baby knew I was anxious to get knocked up? Haha) or if I always have an early ovulation but period the same time each month (since I've never tested ovulation before or after who knows) but I have my first ultrasound in a couple days and am expecting that my measurements may not line up with my last period because of it...long story short, every body is different and as long as there is development at each appt a week or two one way or the other is more likely a reflection of ovulation than an issue :)

    BabyFruit Ticker
    Report Reply
  • BrittwjtkBrittwjtk member
    My due date is January 25th as well and I'm being told I'm 8 weeks 2 days? Something seems off there
    Report Reply
  • sherks11sherks11 member
    I went in on Monday and according to my LMP I should have been 8w1d but the ultrasound showed 7w3d. I have another ultrasound scheduled in a month in order to get a more accurate due date. My doc wasn't concerned at all.
    Report Reply
  • tuitwotuitwo member
    Even if you have always been extremely regular, it's certainly still possible that you may have ovulated later than you think, creating the discrepancy in dates.

    Plus I believe that most doctors won't even change your due date unless the difference is over a week. That's considered a normal variation.
    Report Reply
  • fricktionfricktion member
    I have 28 day cycles like clock work, however I ovulate on about day 18 or 19 so my due date is 5 days later per the ultrasound than based on my LMP.  
    Report Reply
  • JandJ62914JandJ62914 member
    This happened to me too. My first ultrasound I thought I was 7w4d based off my LMP, but I measured 6w5d. They changed my due date.

    This was four weeks ago. I just had my next appointment today at 10w5d and saw my baby dancing around in there! It definitely happens!
    Report Reply
  • sherks11sherks11 member
    tuitwo said:


    Plus I believe that most doctors won't even change your due date unless the difference is over a week. That's considered a normal variation.

    Not necessarily true. My doc changed my due date with dd when it was only a 2 day difference. seems a little silly but he did!
    Report Reply
  • jennymack79jennymack79 member
    Lurking here, (my EDD is 2/1) but just wanted to explain a few things:

    1. Your cycles can be regular and then suddenly not be. Our bodies are crazy like that.

    2. While cycle length and ovulation day can change at the drop of a hat, your luteal phase (the time from ovulation to when your period would be expected) shouldn't vary more than a couple of days from cycle to cycle. That means the first portion of your cycle (period start to ovulation) can vary at any time for any length of time.

    3. It's completely normal for a woman's usual luteal phase to be anywhere from 10-16 days long, though it shouldn't vary by more than 1-2 days for an individual woman.

    4. The "average" cycle is generally thought to be 28 days, with ovulation happening right smack in the middle at 14 days, and a luteal phase of 14 days.

    5. LMP due date calculations assume this "average" cycle, and measure baby size with the assumption that you ovulated on day 14.

    6. If, in fact, you ovulated earlier or later than this "average", your doctor would see the evidence in your U/S.

    So: measuring big and doc moves due date earlier? You ovulated earlier (closer to your period start date) than the 14-day "norm". Measuring small and doc moves your date later? You ovulated later (further from your period start date) than the 14-day "norm". So, as long as your doc is not concerned, I wouldn't be either.

    I know we're all KU'd here, but if you'd like to learn more about your cycle, there are some really great resources out there that, while mostly designed for those TTC, provide awesomely detailed information. Trust me, when I first started TTC, I was SHOCKED by just how little I actually knew about how our bodies work. At the very least, keep these resources in mind should you decide to try for another LO in the future.

    The book: Taking Charge of Your Fertility by Toni Weschler

    The app: Fertility Friend
    Me 37, DH 37
    Married since 4/2004
    DS born 1/20/16, Graeme
    Report Reply
  • jezygaljezygal member
    My due date is 2 weeks behind from when my lmp was, I just ovulated 2 weeks late. My period was a week and 3 days late when I got a positive, so it makes since for me.
    Report Reply
  • ChipMonsterChipMonster member
    I had the opposite happen to me during my last pregnancy. I went in thinking I was 12 weeks and ended up being 13. I had ovulated super early - 2 days after my period. And yes, I have always had regular periods.

    Oh and I got my period back 10 weeks after giving birth last time. While exclusively breastfeeding!! I even spotted at 6 weeks and asked the midwife about it, she said it was probably just "left overs" from birth. Surprise, surprise, 4 weeks later my real period showed up! I could t even catch a longer period break!! Haha
    Report Reply
  • jem8407jem8407 member
    I had a mc last time with major developmental delay but the dr knew it was happening.
    This time, I went in due to bleeding and measures three days behind LMP. I ovulated three days later. I then went in for a check six days later but only two days of growth. I freaked out.
    I just had a scan yesterday and basically was back to four days different. All is well and my doctor's are not at all concerned :)
    Report Reply
  • MamabeagleMamabeagle member
    winters17 said:

    I really wonder how accurate the u/s can be that early? Maybe I never had this problem with my son because I didn't go until 10 weeks!? I've heard the dates can catch up.
    Let me know how the one today is. I think I'll try and schedule another one too.

    Dating scans are actually most accurate in this early time frame, not less.
    Report Reply
  • winters17winters17 member
    Thanks ladies!
    Saw my midwife today, she didn't seem to concerned either but DID change my due date from my LMP (January 25th) to u/s (January 31st). Still feeling odd for some reason.... I go back in three weeks to hear the heartbeat. I hope everything will be ok, but for now, no scheduled ultrasounds. I just have to try and rely on faith and positive thoughts.
    Report Reply
  • KaraEpp16KaraEpp16 member
    jennymack79 said:
    Lurking here, (my EDD is 2/1) but just wanted to explain a few things: 1. Your cycles can be regular and then suddenly not be. Our bodies are crazy like that. 2. While cycle length and ovulation day can change at the drop of a hat, your luteal phase (the time from ovulation to when your period would be expected) shouldn't vary more than a couple of days from cycle to cycle. That means the first portion of your cycle (period start to ovulation) can vary at any time for any length of time. 3. It's completely normal for a woman's usual luteal phase to be anywhere from 10-16 days long, though it shouldn't vary by more than 1-2 days for an individual woman. 4. The "average" cycle is generally thought to be 28 days, with ovulation happening right smack in the middle at 14 days, and a luteal phase of 14 days. 5. LMP due date calculations assume this "average" cycle, and measure baby size with the assumption that you ovulated on day 14. 6. If, in fact, you ovulated earlier or later than this "average", your doctor would see the evidence in your U/S. So: measuring big and doc moves due date earlier? You ovulated earlier (closer to your period start date) than the 14-day "norm". Measuring small and doc moves your date later? You ovulated later (further from your period start date) than the 14-day "norm". So, as long as your doc is not concerned, I wouldn't be either. I know we're all KU'd here, but if you'd like to learn more about your cycle, there are some really great resources out there that, while mostly designed for those TTC, provide awesomely detailed information. Trust me, when I first started TTC, I was SHOCKED by just how little I actually knew about how our bodies work. At the very least, keep these resources in mind should you decide to try for another LO in the future. The book: Taking Charge of Your Fertility by Toni Weschler The app: Fertility Friend
    Thank you for sharing all of this info. I've always practiced the rhythm method instead of taking any form of birth control because I've been very regular. I think it's important for women and especially young girls to know as much about their cycles as possible.

    I assumed 7wks exactly by LMP the day I went in for the ultrasound and they said I was measuring 7wks and 2 days. My pregnancy was not planned ( We're still VERY excited - a year earlier than we would have actively started trying) but we live together and he has known from day one that I wasn't on birth control. The only possible explanation for my pregnancy was a wonky April cylce and ovulating earlier than usual - So, when they told me it was measuring a few days ahead; I felt pretty confident that I was right about ovulating earlier.

    By the way - the doctor said because it was 2 days there was no need to change the due date.

    OP - It just takes that one wonky cycle to throw things off. I wouldnt worry about anything until after your next appointment. I know that is easier said than done. They will be able to give you peace of mind from the information they gather then.
    Report Reply
Sign In or Register to comment.
Choose Another Board
Search Boards
"
"