Feb 062011
 

“Conception date has nothing to do with a due date!” – OB to mother who stated the conception date and why she felt the due date should be different.

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 February 6, 2011  birth, Due Date, OB  Add comments

  96 Responses to “"Conception Date Has Nothing To Do With Due Date!"”

  1. It doesn’t? So, what does the due date have to do with a pregnancy at all then? And, if they have nothing to do with a pregnancy, why are they given out and treated as law??

  2. Ummm….Someone needs to go back to basic human biology and study again. Total Bossy-Pants Fail.

  3. Don’t be silly, of course it doesn’t. It has to do with when the OB is due for his next vacation, how many other women he might get stuck dealing with on that day, and what time his golf game starts at. Also, babies are never conceived during a time in which they might be due on a weekend. Yeesh.

  4. OMG! Where did this doctor got his licence… Oh, yeah, due date has nothing to do with conception – kids appear out of cabbages on a date set by the OB.

  5. My sister, whose children are conceived via IVF, had to fight with her doctor to use the conception date rather than the LMP date.

    Most ridiculous thing I’ve ever heard.

    • I had the same problem… with the same OB that preformed my IUI!!! They also had my 7dpo labs showing I did indeed ovulate on CD 21, and 10 days later told me my HCG was too low, because on CD 31 a beta of 65 = miscarriage. They could not wrap their mind around the fact that my period was not due for another 4 days.

    • I am fighting this issue right now. I put a date down as my LMP, but it was a guess because I couldn’t quite remember. I told the OBGYN that it was a guess because I did IVF. All through my appointment she was fine with what I was telling her, that I was 10 weeks along etc. She said “ok, come in 4 weeks from now, you’ll be 14 weeks.” Now I’m trying to schedule a first trimester screening test and they have my due date 2 weeks off because they are going by the random LMP number I put down. But get this – they won’t change it because they won’t take my word for it. “My word” however, was okay for the LMP.

      • If you did IVF, then they have freaking MEDICAL RECORDS to go by.

        Turn down the screening tests on the grounds that you know you’re going to get a false-positive if they use the incorrect dates. When they argue, argue back that you don’t need to take a test you know you’re going to fail, and since they’ve set it up such that you’ll fail, you don’t want the stupid test.

        They have *medical records* from the IVF that can date the pregnancy. If they won’t take the word of another doctor, then you can diagnose them with a serious case of Ego and leave the practice for another practice that knows how to read medical records. It’s not as if you did IVF in your basement with a copy of The Do It Yourself Guide To IVF.

        • “It’s not as if you did IVF in your basement with a copy of The Do It Yourself Guide To IVF.”

          Thanks, Jane, now I have to wipe coffee off my monitor! ;)

          • I live to serve. :-)

          • Hilarious. :)

            Since these posts were a few years ago I hope that my experience shows things have changed… what my docs did was just look at the date of egg retrieval (from IVF clinic documents), subtract 14 days from that and call the result the “date of my last menstrual period.” They could not care less when my actual LMP was; everything is based on the date of egg retrieval (i.e. fertilization).

            Or maybe I just have more rational doctors!

        • This happened to my SIL too! Her Medwives insisted on going with the dating ultrasound despite her personal and familial history of large babies and would not use her date of conception from her fertility treatments!!!

  6. OB/GYN focuses on the period because it can be observed externally. They don’t like to rely on ovulation date because it’s relying on data collected by the woman, and women (as we all know) are flawed.

    Hence the reason I had to lie about my LMP to at least one practice. If they insist on believing a woman can only ovulate on day 14, then I’ll change my LMP to make it so I did ovulate on day 14, even if that means I got my period a week after I really did.

    • I have a question, sorry to hijack the thread! We are TTC #3 and I was wondering if we only have sex 1 time around the time I’m supposed to be fertile and end up pregnant, so I’d know the day or at least the day before I actually conceived, could I count 40 weeks from then, or is it still 40 weeks from LMP?

      • It’s 38 weeks from conception, or 40 weeks from LMP (because that assumes you ovulate 2 weeks after your LMP).

        So, if you know your conception date, it’s 38 weeks from conception.

        • Wow, I didn’t know that! No wonder my 2nd was born so much “sooner” than my first (who hung out in utero until 41 weeks + 1 day) with my second, I never had another period before getting pregnant again, but I did have bad cramps which after finding out I was pregnant, I assumed that was ovulation and counted 40 weeks from then. My due date was really April 3rd not the 17th! She was born on the 8th.

          • LOL Chelsea! Here’s another “nugget” for you…a Harvard study found that the average pregnancy duration in a healthy woman is 41 weeks 1 day in the first pregnancy, and 40 weeks 3 days in subsequent pregnancies.

      • 38 weeks from your date of conception. However you start counting at 2 then, not zero! So your due date would still be *numbered* as week 40, but it would be 38 weeks from conception.

        • Note: My husband has “Methuseleh” sperm (they seem to last for at least five days, maybe seven) and based on what I’ve charted (and detected in my mucus quality) my eggs last for several days, too. We’re unusual, but we’re not off the bell curve entirely. So there is a bit of wiggle room as to “time of conception,” unless you get bleeding, mittelschmertz, etc that tells you when a fertilized egg has implanted.

          • When it has implanted could be 5-8 days after it was fertilized, so the dates are still going to be approximate.

      • Under ideal conditions, sperm can live for seven days in the uterus, so no. For the most accurate due-date, you’d still want your date of ovulation nailed down.

      • Take your ovulation date (not necessarily the same as the day of baby-making activity) and subtract 1 week, then add 9 months (or subtract 3 months, same result either way). That will be your “due date.” I fudged my LMP dates with my second, FWIW. It was only a few days’ difference, but I am kind of anal about stuff like that, and I wanted my official records to match up with my real due date.

    • It was only a matter of a few days that I fudged. My OB was willing to go off my chart, though, so I didn’t even really need to do that!

  7. So here is a side question… I am pretty sure I know know the day I ovulated, but I am more certain of the day of implantation because of the obvious hormonal shift. How long is it usually between ovulation and implantation?

    • I *think* implantation usually occurs around day 8 post-ovulation. But don’t quote me on that.

    • That’s the thing; just like the follicular phase of a woman’s cycle, the time from ovulation to implantation can vary greatly. It averages about 7-10 days. Yet, some women are able to get a postive at 5 days past ovulation while others don’t get theirs until 13 days.

      It’s a lot more accurate to do things based on when you ovulated. There’s only a 24 hour window that the egg can survive, though in reality it’s closer to 18. If it doesn’t get fertilized within that window, it’s not going to. This is why your body creates specific fluids that allow sperm to survive several days prior to ovulation. Because that window from the time the egg bursts from the ovary to the time that it is no longer viable is so short. That way, intercourse from days before ovulation could still impregnate you.

      • These last two comments illustrate how grey conception and ovulation dating are. Even if one can nail down exactly when ovulation occurred, you don’t know when fertilization occurred, which could be many days later.

        ‘Due Dates’ are just estimates of when the baby will be born. The baby doesn’t know what date we give it, and typically the best course is going to be to wait until labor.

        We know that a first trimester ultrasound crown rump length is accurate to 4-5 days, so if the LMP/Ovulation Date/Conception date is within that window, then OBs set it based on that. If not, OBs recommend using the ultrasound.

        I have heard some doubt the accuracy of the early ultrasound, but this skepticism is not based in fact or science or all (in fact it is based on skepticism of science I think). Every embryo of 1 day is the same size, and they differentiate very little in the early part of their growth. As such, embryos of 6-8 weeks are all pretty much the same same, giving us the ability to accurately date the pregnancy by the size of this early embryo.

        If somebody wants to set dates some other way, then its just going to be another estimate, no more accurate, and probably less accurate.

        • While I agree that it is another estimate, so long as a woman is taking the time and care to know her cycles, I think it’s likely to be much more accurate than an LMP. The luteal phase doesn’t get affected by external influences, so if I know when you ovulated and you know how long your luteal phase generally is, the ovulation date is much more accurate, particularly if there was a stressful event that took part during the follicular phase. Moving, being in a play, any major disruption of life, an earthquake… etc, anything stressful enough can delay ovulation and screw with the length of the first part of the cycle. A charting woman can know exactly when she ovulated and can make a much better determination on when conception occurred that just assuming that the LMP was 14 days before she ovulated. It doesn’t set the due date in stone, but it can prevent a baby that is really only 39 weeks gestation (though 40 weeks from LMP) from being induced or c/s. It would be nice if more medical personnel recognized that there can be discrepancies in healthy women’s cycles from what is considered “normal” and that those discrepancies do not make her knowledge of her body less reliable than a cardboard wheel. Some women may have no clue, but in many of those the LMP doesn’t help much either and an early ultrasound may be the ONLY way to determine due dates. But we shouldn’t just assume that all women are totally clueless when it comes to this stuff.

        • Fertilization has to occur within 24 hours of ovulation, otherwise the egg dies.

          What you’re reading in my previous statement is the time from ovulation to implantation, which is completely different from fertilization. Implantation is where the fertilized egg burrows into the uterine lining.

          As far as the accuracy of the early ultrasound dating, you’ve said it yourself in previous posts that the early dating is accurate to within 3 days. And yet I’ve seen woman after woman on the pregnancy boards have their due date changed by one or two days because of the ultrasound. What is the point in that? But then, these are the same women who undergo multiple ultrasounds throughout their pregnancy and their doctor will change their date almost monthly based on the ultrasound, or the fact that they’re measuring a little bit further ahead, etc.

          And what about a woman like me? I refuse to get an ultrasound done in pregnancy unless it is medically indicated. However, I can tell you that my last “period” (I put that in quotes as it wasn’t actually a period, but in fact the end of a chemcial pregnancy) was August 27th and that I ovulated on September 14th, with positive pregnancy test on Semptember 26th. Or what about with my first pregnancy, where I *did* see an OB and went through everything? My first appointment wasn’t until I was 11 weeks. My first ultrasound wasn’t until somewhere in the middle of my second trimester (I can look at the picture and give you the date, but I couldn’t remember what week it was). Obviously, there was no early ultrasound dating. My date was based solely on LMP. Had I been charting my cycles then, I could possibly have had a different due date (which he never once changed throughout my pregnancy)based on ovulation. I don’t know about before ever getting pregnant, but since having my son I don’t typically ovulate until between CD19 and CD21. The difference in LMP due date and ovulation due date would be about a week. With many doctors out there, that one week can mean the difference between spontaneous labor and bullying the mom into an induction.

          I can understand where you’re coming from with the measurements being most accurate from ultrasound, I really do. However, for a doctor to say that the date of conception (and equally the date of ovulation) has nothing to do with what your due date would be is a *completely* false statement. One that is designed to make the woman feel as though she is stepping into territory that *only* the doctor should be in. It is calculated to make the woman unsure of herself. I mean, after all, if she doesn’t know how to calculate something as simple as a due date, what else is she incapable of figuring out? Best to just leave it all in the hands of the capable doctor and not worry her pretty little head over anything.

        • While I agree with much that you have said, I am puzzled by your statement that fertilization can occur many days after ovulation. While it is certainly true that fertilization can occur many days after intercourse (due to how long sperm can live), and also true that implantation can occur a variable length of time after fertilization or after ovulation, I am not aware of any research or information that states that an egg can live longer than one or possible 2 days after ovulation. So fertilization HAS to occur within a very small window after ovulation or the egg does not survive and no pregnancy occurs.

          It seems like from this that the primary difficulty of using an ovulation date is not its accuracy in predicting fertilization and therefore dating of the embryo. Rather the difficulty is the reliability of the source of the ovulation date, the woman. And that is what many on this thread are complaining about.

          While first trimester ultrasounds seem to be fairly good predictors of gestational age (and probably more accurate that LMP.. date of intercourse.. or date of implantation) it is difficult to believe that they are necessarily more accurate than a known ovulation date when available.

          For myself in my current pregnancy, my ovulation date was known through 4 separate sources. 3 of these I observed myself and one was known to my OB (serial progesterone results including the day of and 2 days after ovulation showing a significant shift from levels typical for ovulation to levels typical of the luteal phase. So I was somewhat frustrated when a first trimester ultrasound was recommended to confirm dating. From my perspective this was a somewhat expensive test (even though my insurance would be paying) that I simply did not need.

          • Maybe you’re right on egg life. I’ll ask an REI colleague to confirm.

            >>It seems like from this that the primary difficulty of using an ovulation date is not its accuracy in predicting fertilization and therefore dating of the embryo. Rather the difficulty is the reliability of the source of the ovulation date, the woman. And that is what many on this thread are complaining about.

            Well said. This is indeed the issue. Most OBs deal with this by just scanning everyone, as its hard to tell who’s going to have an accurate idea of when they ovulated. I’ve had plenty of patients who claim absolutely sure, but their ultrasound shows them to have conceived a clinically significant amount of time off from when they thought (7+ days). Some non-OBs would interpret this as inaccuracy of ultrasound, but I don’t think this would be the correct interpretation.

            Ultimately, if you are absolutely sure when you ovulated, the ultrasound is going to confirm that date and you will have set the due date.

            One thing to realize is that first trimester dating scans, in the absence of vaginal bleeding or some other real issue, are not billable. The OB is doing the scan because it improves the quality of care, not to make money. I never bill for these, and if I did and was audited, they would get kicked out and I would be penalized by the insurance god in the sky.

          • The problem is that the ultrasound accuracy is only as accurate as the tech. When an OB (or anyone else) takes it as gospel that the date the ultrasound comes up with, we start getting away from care of the individual mother/baby pair, and toward cookie cutter medicine. With my oldest I was told we were going to need to induce because I was “post dates” (three days after my the earliest but most recent EDD they had given me) but I was also almost a month away from the EDD they first gave me (both from ultrasounds)- I told them we’d wait until all the due dates had passed unless my child started showing signs of problems. I had a spontaneous delivery exactly in between the two dates. (Dates I was given were 10-31 and 11-23; my son was born 11-13)

          • I forgot to mention that with my first I found out I was pregnant in April, and my LMP had been in- April. I never missed a cycle until after finding out I was pregnant!

          • How many weeks were you at the ultrasound? With my son I had an 8 week, and I came up with an EDD of July 28th. My 20 week came up with an EDD of July 2nd. My midwife refused to even look at the second date, and I went into labor on – you guessed it! – July 28th.

            The 8 week with my daughter was within a couple of days. And both were about a week off of where I expected. I’m a believer in the 8 week ultrasound!

          • STM NFP rules say that three days after a woman observes higher temperatures, she’s in the infertile luteal phase. Since the temperatures rise in response to ovulation, that gives us 24 hours of egg life, plus 24 – 48 hours leeway for the temperature to have risen prior to ovulation. I think it’s pretty well-established that the egg only survives 24 hours maximum after it erupts.

            The really amazing feat is that the sperm can survive under ideal conditions for seven days. So even if a woman says to her OB, “We only had intercourse on day 12,” that doesn’t mean she conceived on day 7. She could have conceived, theoretically, on day 19.

            This wouldn’t be a huge problem except for doctors who start pressuring moms to induce at 39 weeks.

          • I think the bottom line on all of this is, as stated by another commenter– it’s not that critical to know the EXACT date of conception nor the EXACT “due date.” Doctors know (or should know) that it’s a range. It should be treated as such. If women weren’t considered “overdue” until at least 42 weeks, bare minimum– and even then, for at least another week or so, just closely monitored and “allowed” to continue unintervened as long as NSTs, etc., looked good– then none of this would be an issues.

          • Excuse me– an issue, singular.

        • When you have a doctor willing to wait for labor, fine. When you have a doctor who insists that anything past 41 weeks is basically a stillbirth… You use the latest date you can manage.

          • Why would you use the latest date you can manage? IOW, why, when you know you’re already at least 40 weeks along (i.e. the baby is fully mature), would you fudge your dates to the doctor just to keep the baby inside despite the increasing risk of stillbirth?

    • Thanks for the info everybody! I am in an interesting position… Due date according to LMP was March 26. I knew this was wrong b/c my regular cycle is usually 36 days long (I generally ovulate a week+ later than people w/ a 28 day cycle.) The date I calculated ovulation+38 weeks was more like April 1.

      Once I had an early ultrasound though, they dated me as due April 6. (according to the US tech who went over it after I changed practices, the ultrasound was pretty unclear, so I’m not so sure about that one being the day.)

      I think I’m looking at an April 1 baby and at least no one will be bugging me about inductions and such till a week or two later. I feel like this is an opportunity to just watch and wait to see which is more accurate. :)

  8. Oh the stupid! How it burns!!!!! :/ I had to harass my providers when I was pregnant with my VBAC baby, as they insisted on the LMP date, which I KNEW was two weeks early. I mean, I was charting to conceive, and knew my ovulation date as well as recorded when we had sex. I KNEW. Idiots. If I’d listened to them, they would have been fearmongering me about being 41 weeks or more when I was truly only in my 39th week! And what do you know, baby girl came on her own time, one day shy of 40 weeks. ;)

  9. [...] This post was mentioned on Twitter by Claire Louise Lloyd, My OB said WHAT?!. My OB said WHAT?! said: New Blog Post!: "Conception Date Has Nothing To Do With Due Date!" http://bit.ly/gVzVNX [...]

  10. I had an L&D nurse say that I couldn’t possibly be sure what the day of conception was, you never can be sure even if you take your temp. I told her that if she looked down at the chart she was holding, she would clearly see the day I had my artificial insemination.

    So yeah, I’m pretty sure it was August 28th 2009.

  11. I am pretty sure even the OB is face-palming this one. He/She must have been tired cause that’s a pretty silly thing to say.

    I went in early in my pregnancy because I just *knew* something was different and I was expecting. I also knew the conception date because my husband is military and there was only one time that we were in the same place at the same time. My first EDD was right on the money my second (by ultrasound) was way too late. I didn’t tell a soul. When my kid came out big and strong and healthy everyone was surprised I actually gave birth in the 40th week. That’s when I let them know the date was wrong and I gave birth in the 41st (almost 42nd) week (like an average of first-time moms). Without an induction too. Boo and Yah.

  12. Dr. Fogelson, Lauren has hit the nail on the head. The reason this is even an issue is that women are under tremendous pressure to consent to an induction after 40, 41, 42 weeks. Or we have midwives who are legally required to transfer care past 42 weeks.

    And I’ll take your word about the accuracy of early ultrasounds, but isn’t it true that the sonographer’s skill at determining crown-rump length is a factor?

    • The measurement of length is a lot easier to get early on because there isn’t quite as much movement and also not quite as much room for error. Thus why they say you get a range of 2-3 days from their EDD in an 8 week where you can get a variation of a week and even more at a 20 week U/S.

  13. Ugh, my first pregnancy!! There was only *one* weekend that my now dh and I were together. Long distance relationship. I had long/irregular cycles though. So I went to a CNM (one that has a very good reputation in the natural birth community but I suspect my care was less-than because she saw me as a young, dumb mom.. I was 19) and told her my LMP. LMP put me at Feb 1. I had a suspicion that I ovulated a day or 2 after my bf flew home (no way of verifying that) and I calculated my edd myself based on that ovulation date. It gave me Feb 10. Which is significant if I know I’m 40w4d and she thinks I’m 42w!!! So even though, as has been stated in this thread, sperm can survive up to a week in the right conditions, that would give me an even later due date. There was *no way* my due date could be more than a day or two earlier than the date I gave myself, unless I was pregnant with Jesus himself. NO. FREAKING. WAY. POSSIBLE. Feb 1, as a due date, was *impossible* She insisted. Then I had my ultrasound, at 18w5d by my dates. And I know ultrasound is a lot less accurate in the 2nd tri, the ultrasound put me at exactly 18w5d! So when I talked to the midwife at my next visit like, “will you believe me now?” she said… oh, we only change the due date if its a 2 week difference. “but you’ll probably go late” and I wanted to scream, “but if you think I’m 42 weeks are you going to demand induction when I’m only 40w4d!?” So. Irritating. I switched to a home birth midwife. And went into labor on Feb 1 anyway… rofl. Go figure.

    • Just like any stage of life, every baby grows at their own rate. Some are going to be ready earlier, some take some extra baking, even if you know the exact date of ovulation.

    • LOL. I had something similar happen. my first midwife (a home birth midwife) refused to take my conception date into consideration even though it moved me back by a week (I ovulated on the 21st day that cycle, not the 14th). I knew she didn’t believe in induction anyway so I didn’t fight it. then my kid decided to come 8 days early (by my dates, or one day early by the due date the MW gave me!)

      • I conceived my 2nd with the first pp egg, so it had been like 3 years since LMP. So they had to go by MY date and my date alone! hehehe. I had a positive OPK so I assumed the O date to be the day after that. Course it didn’t matter since my CPM was perfectly happy to go with my dates regardless, LOVE her! It was funny when i went in for my 20 week ultrasound. It was dec 08 and she asked for my lmp and I said april 06 :D Reaction to that is priceless. So she was like, “ooookay! Whats the due date then?” its nice catching the first pp egg.. COMPLETE control! WOOT!

        • Ugh. I can’t tell you how many times I’ve had an OB or nurse freak out when I give an LMP that is a couple of years past. It is especially disturbing to me when I have several small children with me, including a nursing baby. In one case, the nurse who was taking my history stopped and wordlessly left to get the doctor, who came in ready to do some gyn work on a “problem case.” In another, the nurse interrupted me to ask if I had had a hysterectomy–I happened to be nursing the 6-month-old in the exam room at the time. Do mothers not nurse there babies anymore, or do OBs really not understand the effect of nursing on ovulation?

  14. I was told some variation of this in the ER after a car wreck at 19 weeks along. I was charting and was 100% sure of my dates but by ultrasound the baby measured a week ahead. The ER doc argued with me that ultrasound was far more accurate. I was thinking WTF–the ultrasound wasn’t in my bed temping and checking my mfing CM.

  15. Due date has nothing to do with due date. If a first-time mom (on average) goes to 40+9 then in reality a due date doesn’t tell anyone anything. So regardless of the “science” or “ovulation” or “LMP” its all a freaking guessing game anyway. Don’t put moms on a clock!

    Being a VBAC with a long cycle, I had to lie about my LMP. I calculated my LMP by subtracting two weeks from when I know I ovulated. The only people who knew when my LMP really occurred was myself and my husband. My HB midwife knew that I smudged my LMP to her (because I told her) but also knew that there would be no way I’d tell her the actual date (dates are important to the MN legislature as an HB MW can’t see a pregnant mom after 42 weeks). The doctor was already ready to cut at 39 weeks, can you imagine what she would have done if she thought I was closer to 40 1/2 weeks at that time?

  16. The date of conception is probably MORE relevant to a due date than LMP. That being said, as many have alluded to here, the biggest problem is that many people (some OBs, some midwives, and MANY parents) forget that the due date is an ESTIMATE. It is normally accurate within 14 days either side of that date. Thus, being 10 days late is no more “overdue” than being 10 days early is being “premature”.

  17. Of COURSE conception date has nothing to do with due date. The all-seeing all-knowing cardboard wheel scoffs at your pitiful fertility charting.

    Due date has very little to do with reality anyhow. The method for determining due dates is flawed from its very premise, is it not? I understand it to be based on a theory proposed by a doctor several hundred years ago, and not actually backed up as accurate by scientific means.

    I know what date my LMP was.
    I know what date I had intercourse.
    I know to within 48 hours when I ovulated (a few days later).

    I gave my midwife a date close enough to that data that the cardboard wheel would indicate a reasonable day that my baby might be born +/- 2 weeks, and also with no risk of her backup doctor feeling any pressure to ask me about induction until I am most definitely at or beyond 40 weeks by my calculations.

  18. With my first baby, I ovulated around day 24. LMP would’ve put me due on July 31. I calculated my due date as August 9. I was seeing a homebirth MW so she was quite laid back about it all anyway, but noted that my measurements corresponded with the date that I gave her.

    I went into labor 10 days after my due date and gave birth 12 days after my due date, at 41w5d. The midwife noted in her exam that my baby had the appearance of a 41 week gestation baby.

    If you go by my LMP, though, I would’ve been 43 weeks!

    2nd baby: I ovulated on day 26, so instead of February 14 as my due date, I calculated it at February 26. I went into labor on February 26 and had him on February 27.

  19. I am dealing with Due date issues too. According to LMP I am due May 5th, according to Ovulation I am due May 10th, according to early ultrasound I am due May 7th, and according to late ultrasound I am due May 5th.
    My due date has been changed 3 times! I count how many weeks I am according to the Ovulation date because it is the latest but I think my OB is going with the earliest date. This makes me nervous because if it is wrong then I would be labeled overdue when I am full-term.
    The other downside is when people ask me when I am due. I have no clue which date to say so I just say early May.

  20. After reading all these posts, all I can think is it’s sad women have to lie to their doctors to get the best care for themselves and their babies. But that’s the world we live in nowadays.

  21. I am an example of strange cycles. Some are 45 days, some 26. And my OV can happen on day 9 and on day 30 (according to saliva tests and temperature readings). I got pregnant on a short cycle (OV day 11) and estimated my due date as 23rd of June. The LMP was 26th of June and first ultrasound at 8 weeks put the due date on 2nd of July! Later ultrasounds corrected it to 24th of June. Baby was born on 12th of June. So in my case the first ultrasound was the worst estimate and luckily my due date was not set by that, otherwise I would have been required to birth in a hospital because the baby would be considered prematurely born.
    This time I ovulated on day 9 and ultrasound also shows that the baby is ahead of the LMP by a week, which again is important, because if he is born on week 38th and documents show 37, my midwife will be in trouble.
    That is the biggest problem – we could just calm down and not count all these things if women with late OV would not have to hear from ultrasound techs that their babies are not viable because they are 2 weeks smaller than should be (at the first appointment), or get induced because they are past 41 weeks (although are just over 39), etc.

    • My cycles are pretty irregular, too. I practice Weschler-method fertility awareness… as a secondary form of birth control (we also use condoms and spermicide, which is uncomfortable for me because I’m allergic to nonoxynol-9, but we’ll both be getting spayed before my cycles resume anyway). Mostly I use FAM to predict when I’m about to get PMS, so I can warn my husband to keep away from me for a few days so I don’t bite his head off. ;)

      • Due date? What’s a due date? Seriously, in my case, my midwife just shrugged and considered my due dates more approximate than most. Doesn’t help much that I also had no idea when my eggs got fertilized and implanted.

  22. Hmmmm, so very interesting that we just can guage a due date without all the highly evolved technology. Women can’t possibly be tuned to their own reproductive cycles!

  23. The wheel! You insult the magical wonder wheel!

  24. In Soviet Obstretrics, Due Date Chooses YOU!!!

    Or rather, “Conception date has nothing to do with the due date I assign you.”

    Even at my most charitable, this reads as if the doctor is trying to explain (in as jerky a way as possible) that 40 weeks is calculated from the LMP, not conception, a concept which many women are fuzzy on. But “nothing to do with?” Um, okay.

  25. When I told my last doctor I didn’t remember my LMP date but I knew my ovulation date and my implant date the first words out of HER mouth were “we will send you for a dating scan then.” I got so made I changed doctors. When I send this to the new doctor, HIS first words were “how do you know when you ovulated & when the embryo implanted” in a genuine “explain it to me” voice. So I explained to him about charting and my observations about body changes including but not limited to tiredness, migraines, weird dreams, couldn’t stomach certain foods all of a sudden, morning sickness, breast tenderness etc etc, and when I was done he nodded and asked how far “out” the scan date was to mine and I said 6 days (scan date is 12 August, my date is 18 August) then I pulled the ace out, my husband works away on 6-8 week shifts and I knew the days he was home, the very earliest I can be “due” is 18 August.
    With DS, there was 3 weeks difference between my dates and the scan dates (again, husband was away but “the 6 week scan is most accurate”. The whole pregnancy was stressful because at every scan the baby was measuring “3 weeks too big” but they wouldn’t change their dates. In the end it was a blessing, he was born 41+3 my dates but just 39 wks their dates (thank god their dates gave me up to an extra 5 weeks to GIP, they were “allowing” my to go to 42 wks, their dates). He was born, happy, healthy and skin peeling off him everywhere, just a bit “over done”.

  26. No, time of conception doesn’t have much to do with a due date.

    And due date has very little to do with when a baby actually decides to be born.

    Now that THAT’S out of the way, can we talk more about twinkle lights, aromatherapy drums, and belly dancing doulas?

  27. Original Poster here… Yeah, we didn’t end up going with the OB, who also gave us a big old scare regarding birth defects due to their “accurate” dates.

    We went with a midwife who believed my information, and when I started getting a little anxious near the end of the pregnancy, and really ready to be done, she told me, in her gorgeous Indian accent, “Go home and be fond with your beloved. Fondness puts the baby there, fondness convinces the baby to come out. Relax! Babies always come out!”

    We ended up delivering within days of the date I had figured (based on conception). I guess I did relax… when I finally decided that it was really, truly labor (having ignored it most of the day), we had 40 minutes to a simple delivery, with my husband catching.

    I’m so glad my parents raised me stubborn.

    • Momma tried to raise a lady but daddy won they raised a lady that don’t take shit from anyone

      as a woman with 43 day cycles 14 days past lmp means nothing and stubborn is good

  28. Maybe we have the same stupid OB. LOL I found out I was pregnant about 6 weeks ago and the dr told me I was 13 weeks, I go back this month and he tells me I am 14 weeks. ???? My last period was Oct. 24 so how in the world can I possibly only be 14 weeks? Based on my own calculations I should be almost 18 weeks now but according to this genius dr I’ve only gained a week of pregnant in the past month.

  29. hi my name is ashley i saw my period in march not sure the date i went to visit my bf in april had sex like 14 days straight i didnt c my period in april at all i felt different n i know i was pregn my period had always been irregular how ever wen i went to c my doc my first due date was January 29 the wen i did my ultrasound they push it back to feb 8th n said i got pregnant in may but my baby didnt come until the 15 im confuse lost and dnt know wat to do cuz not my bf is mad at me sayin my baby aint his is it possible i got pregn in april n gave birth in feb i was 41 weeks wen i gave birth plz help me

    • I am sorry you are having a rough time.

      It all depends on when you ovulated. If your last period was in March, and you didn’t actually ovulate until May, when you went to visit your partner, then obviously you conceived at that time.

      Going to 41 weeks or more is quite common for first time mothers. And getting pregnant in May would absolutely give you a due date of February, no question.

      ((HUGS)) to you!

      • thanks alot for ur answer but are you saying i can get pregnant in april but it actually didnt show up until may? cuz thats the only way i can look at it u made me feel much better with ur replay..:-)

        • OK here’s some interesting biological facts:

          Sperm can live for a week or so under optimal vaginal conditions, meaning when you have fertile quality cervical fluids.

          So, you can have intercourse in late April, ovulate and conceive in early May, and give birth in February.

          Does that help it make a bit more sense? I hope so! :)

          • it sure does lol thanks alot kat i feel much better :-)

          • That is hilarious…and I beleive that. I ovulated after my husband left the country by two days and i’m prego…so i got a red hot ovulation stick two days after we had sex…and so conception might be 1 or two days after that? I’m amazed at the body after dealing with this situation and finding out we’ve got babydust!

          • To clarify above, I beleive I got prego about 4 days after we has sex. that is amazing!!

          • Oh yes, with my second child I was charting to conceive, and ovulated 4 days after sex….BAM! Pregnant. :D

          • I know with one of my kiddos exactly when he was conceived. I was charting. We had intercourse on day 14 and I ovulated on day 18. That was the only time we had intercourse during the fertile phase. It was kind of neat during that time, thinking, “I’m not pregnant…YET!” LOL. I was pre-pregnant.

          • Yep, our bodies are amazing.

            I am currently pregnant, and I believe I actually ovulated 3-4 days after the act occurred.

            The theory is supposedly intercourse the day before or day of ovulation is supposed to make a boy more likely, and several days before ovulation is supposed to make a girl more likely.

            This baby, conceived via intercourse a minimum of 3 days before ovulation based on symptoms, is ALL BOY (and definitely not shy either).

          • The sperm that started our little girl was 3 days old before my basal body temp started to rise, but who knows if it’s just a coincidence?

  30. im sorry i mean they say i got pregnant in march

  31. no may smfh im lost right now

  32. A lot of the women commenting u all track ur periods and oculations but what if u don’t have normal periods I havent had a period every month since 2004 & and I became sexually active it’s gotten worse I didn’t realize that was possible it was every couple of months then one every 3-4 now when it happens it’s just spotting pretty much

    • I started tracking my periods and ovulations BECAUSE I hadn’t had a normal period in six years. :-) When I had a 92-day cycle with what appeared to be about six attempts at ovulation, my mom sent me the instructions to the sympto-thermal method, a packet of charts, and a basal thermometer.

      And from then on, even when my cycle was 75 days long, I knew exactly what day I ovulated and exactly what day I’d get my period. Irregular cycles is exactly why fertility tracking was invented. :-)

  33. This is all so interesting, I’m 6 weeks and 6 days going by my lmp, presuming I conceived on day 14. But thing is I don’t know when I ovulated, I slept with a male friend a one off thing on day 6 of my cycle and was with my ex on day 14 and day 17, I’m going for a scan at 8 weeks and thinking I won’t mention that I know the last date of my period or they will just add 14 days and give me that date for conception? I hope I’m pregnant with my ex, even though he is my ex we have 2 kids together already and we’re on good terms. We broke up a year ago as he was cheating on me and lied a lot so I could never trust him again. I have told both guys the situation and that I’m hoping scan will make things clearer. Problem is now after seeing comments here about
    Sperm living for 7 days does that mean that the sex I had on day 6 of my cycle could have lasted to make me pregnant on day 12 if I ovulated early??
    Thanks for any help x x

  34. Research has me confused! Anyone know if ‘average/normal’ hcg level charts are calculated by true (if you know exact date conceived) conception date or if this is based on when the ob/gyn feels you have ovulated/conceived? first hcg was 400 22 days from conception (i know exact date) and 4900 second test 36 days from conception. from what i can tell i am low on hcg at second test as charts say it should be at least 7650. i have to wait 2 more weeks til i test again – had prior miscarriage so nervous!

    • If your doctor has the wrong ovulation date, then yes, the numbers will appear low to the doctor when they might be just fine for the pregnancy.

      I know nothing about HCG numbers with regard to whether your numbers are low or high.

      Good luck.

  35. I only get something like 4 or 5 periods a year (before you say lucky they are horrific, and last 9 days the first of which I am bedridden even when I was on the pill and got them every month), but like my mother I ovulate a couple times a month completely randomly. The OB will not believe me that my period was 2 months before conception ( was stressed and planning my wedding) for some reason even though my wedding day, the baby measurements, and when I felt I conceived match up perfectly with that nice 2 week bumper at the beginning.

    I wish I could just use my general practitioner because it took me years to find a doctor who would actually listen when I spoke about other issues instead of brushing it off.

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