Due Date Changed Due to Ultrasound?

Updated on September 22, 2010
C.N. asks from Chicago, IL
20 answers

My original due date was October 4, but it was changed to September 18 based on my 27 week ultrasound (my first ultrasound). I've heard that later ultrasounds are not very accurate, so I am concerned that the September 18 due date is too early and I will end up being induced because my baby is too "late" when she really isn't.

My second ultrasound calculated that I would be due around September 25, which also corresponds with the fundal height measurements I've had throughout my pregnancy...

I'm curious if anyone else has been in a similar situation??? I'm trying natural induction methods and hoping the labor will begin on its own!

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So What Happened?

Thank you all for your advice! My cycles are extremely regular and I am almost certain the conception date was right around January 12. I definitely feel more comfortable with the October 4 due date. My induction is scheduled for October 2, "42 weeks." I have to go in next week for nonstress test and fluids check so if baby doesn't come, I'll talk to them about pushing induction back a few more days...

UPDATE: I was induced the morning of October 1 because of low amniotic fluid levels. Our daughter's skin was very dry but she was completely healthy. Since birth, she's been growing and developing very well, and has stayed around the 90-95% percentile for height and weight. That leads me to believe the ultrasound date was incorrect. However, I am still grateful they changed my due date because if they hadn't, we wouldn't have known my amniotic fluid was so low, which could have harmed our daughter the longer she was in there!

Featured Answers



answers from Chicago on

As long as there is no medical reason to get the baby out, you can refuse an induction. You could go until you are 42 weeks pregnant. Baby will come when s/he is ready- not the doctors.

I have to say, I would be confused too with all the dates they are giving you. Sept 18th is three weeks away from Oct 4th. That could mean NICU time (due to development of the baby's lungs) if s/he isn't ready to come out yet.

1 mom found this helpful


answers from Houston on

I had 4 due dates... not a single one was correct. They were based on the date of my last period, the sonograms, the height of the fundus... It's a science, but not an exact one when the baby will come.

They induced me on the first b/c the placenta was too calcified to the Dr.s liking, but I was 4 days overdue anyways.

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answers from Austin on

Your baby is the only one that truly knows when its due date is. The so called due date should really be changed to a due month. I am a midwife and the mother of 3 children. With the last two I did not even get an ultrasound. My 3rd was born this past April and I never even told anyone the when the so called due date was. When people asked when I was due I said, "oh around end of March to the middle of April." She came on April 16th. You are right, later ultrasounds are very inaccurate and they should have never changed your due date based on ultrasound. Do not let them induce you unless there is a clear medical indication and I am talking your baby or your life is in jeopardy. Let your baby come when it is ready.


3 moms found this helpful


answers from Fresno on

With my first baby, she was due September 25 originally. Then with my ultrasound they changed the date to September 20. She decided to be born on the 13th. Go figure! Like the other moms have said, the baby is the only one who REALLY knows her due date! I can't imagine they would induce you based on an ultrasound due date. Just relax and let it happen when it happens! Congrats on your baby!

1 mom found this helpful


answers from Rockford on

I cringed when reading this because I remember my youngest son's birth. I had a c-section with my first and wanted a vaginal birth with this one. I was to be induced to ensure the baby wasn't so overly developed and too large for me to deliver as my first was. The doctor decided the date after reviewing ultrasounds and I was induced. My baby was decently sized, almost 8 pounds, but he still needed some time to develop before being born. He was healthy and fine, but he was unable to suck and swallow properly, had an underdeveloped digestion system, and had no fat on his bones. My poor little guy was just skin and bones - saggy elephant skin at that! I felt so bad for him, but I was lucky he did not need any intensive care or delays in the hospital. I would wait if I were you!

1 mom found this helpful


answers from Seattle on

You can't be induced without your consent unless you're unconscious, and even then your husband would have to consent.

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answers from Portland on

They do not induce based only on your suggested due date. The due date based on the ultrasound is just a suggested due date. As Momma L. said, due dates are based on different criteria. They induce when a number of things that indicate the baby or mother may be in trouble, line up and concern the doctor.

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answers from Chicago on

what are they basing it on? size of baby? i cant tell you how many times they have said a baby is a lot larger than it really is...happens ALL the time. I would discuss it with the doctor. say you are pretty sure since you are regular and you know the last date of your cycle that its wrong. I mean that is a HUGE difference! What if they induce you when baby isnt developed properly? Lungs need to be developed and 2 or 3 weeks of cooking will do the baby good. Remember its up to you, its your body and your child so YOU are the boss! Dont forget that!

1 mom found this helpful


answers from Savannah on

Just to let you know they cannot force you to get induced. Doctors will tell you they want you to do x,y,z and ultimately you can refuse. Obviously...doctors tend to have your best interest in mind and you hope they do not do things unnecessarily. But you can refuse to be induced if you want to go naturally.
My doctor suggested I become induced and I asked to wait a few extra days and poof I went into labor on my own.


answers from Norfolk on

In my case we knew exactly when conception took place almost down to the time of day. With IVF/ICSI you know. My very first ultra sound said my due date was Oct 27. Later ultra sounds said I was due about 10-14 days later. I'd had no Braxton Hicks at all, and we knew our son was going to be a big baby, but I have wide hips and a big pelvis. I got up to use the bathroom 3am Mon morning and lost the mucus plug. But I still didn't feel anything and sometimes you lose the plug and you form another one. But then by 5 am I began starting to feel contractions. 36 hrs later - precisely on Oct 27 at 4:59pm, our son was born vaginally (9 lbs 1.5 oz, 21 in long). Unless there are signs of stress on you or the baby, I think it's best to let nature take it's course and let labor start on it's own.



answers from Columbus on

My Dr said he always sticks w/ the first ultrasound date b/c it's more accurate.



answers from Wichita on

My oldest son was born at 28 weeks gestation, but was measuring at 26 weeks gestation. Ultrasounds can be 2 weeks off either way. If you are really worried you could ask your doctor to do an amnicentisis to check the baby's lung development before the induction. Then you will know for sure if your baby will have breathing problems after birth.

God bless!


answers from Dallas on

Yeah, don't go by any sono that's not in the first tri. I had one in Dec and said I was 6w5d (I didn't know my lmp).....okay, cool, and so any susequent time I had one they always told me he was 1-2 wks behind that. It depends on who is doing it..because in May I had a totally new OB who knew what he was doing and told me my son was right on schedule. He was born July 12 (edd July 22) and perfectly healthy :)


answers from Dover on

The earlier the ultrasound, the more accurate they tend to be barring any complications. With my son, my due date was Oct 5 but the ultrasound indicated Oct 15 (which was more in line with what I thought). So they had me down for an induction on Oct 17 but went in labor on my own. The tend to let you go a week or two over and don't typically change due dates if they are within that two week either way window.



answers from Grand Rapids on

I would question more as to why thye are changing the date. I could see if it was a few days, but they changed it by about 3 weeks. I do know that the later ultrasounds are not accurate at all because you can't get a good read on certain factor that they need to determine the due date.

Both my kids I had due dates based on ultrasounds given at about 8 weeks along. Both of my due dates where accurate and were actually EXACTLY correct. One came early and one late. I can say they were correct because of what they doctor's saw as the gestational age after the babies were born. When i had later ultrasounds, it did show my last one should have been beginning of august, instead of middle of the month, but my doctor said that just shows the growth. And they do have growth spurts.

i was induced with both kids, and would say that unless you are at the oct 4 or later, i wouldn;'t let them unless there were other reasons. I had a friend who her original due date was july 20, then they changed it to july 7, at her 20 week ultrasound. she didn't have him until July 22. They induced her, and sure enough the 20 was more of when he should have been due. So she was lucky they didn't push her to have him at the beginning of july.



answers from Chicago on

Congratulations on expecting a baby! My first child's ultrasound measurement turned out to be totally wrong. He was expected in early April but there were no signs of distress in the pregnancy and he was allowed to go three weeks past the due date and arrived in late April. This kid later grew to 6'4" tall (and I believe the ultrasound measurements are aligned to average size baby). We have always been thankful that doctor allowed him to continue growing inside me and allowed us to wait for contractions to start and let the contractions determine his delivery date.
If there are any signs of distress during the end of the pregnancy, I totally understand how the doctor might want to help things get finished more quickly as they are considering your vital signs and your baby's vital signs.
You might also want to consider a consultation with JoAnne at www.birthlink.com as she has a lot of experience in providing resources for pregnant Moms.
prenatal yoga teacher
mom of 3



answers from New York on

first, a couple of things. is your period normal? always 28 days cycle? do you know the conception date?

i imagine they first told you oct 4 only based on your last period. now for me, i knew the exact date of conception which was 8 days later than they were saying. the doctor kept using my LMP, so when i went for my first ultrasound, they told me i might be miscarrying, and when they went to look for the heartbeat on the doppler, they couldnt hear it. even though i explained i ovulate late, we used OPKS, and my husband was out of state the week they thought i conceived, they still used the earlier date causing me unneccessary worry and followups. after the heartbeat issue, they officially changed my due date to what i told them which was exact on the babys development by all their tests. so last periods arent a sure indicator unless you ovulate day 14 every month and have 28 day cycles, which many woman dont.

that all said, if you had had an early ultrasound, they are reliable since fetuses have developments at specific times those early weeks. like a fetal heartbeat or yolk sac only happen within X days of a pregnancy. so if you had an ultrasound at 6 weeks, i would put alot of stock in the date they gave. when you get to be as far as you are though, there are easily discrepancies of 2 weeks in terms of estimating a due date, so its just not as accurate in terms of due date.

sooo, unless you know the date of conception, i wouldnt necessarily say the original date was exact since you didnt have an early ultrasound. if you are someone who doesnt feel comfortable to be forcibly induced unless you are 2 weeks late, i wouldnt even worry. due to the second ultrasound equaling your measurements and being in the middle, maybe thats the safetest to go by. but i would still make sure to have the baby by october 2, that way it will either be on time or 2 weeks late. (i personally would never let a baby go 2 weeks late because of a friends experience, but thats a personal decision. if it were me, i wouldnt go past the 25th since there was a possibilty that would make you 1 week late) for you, i would just make sure not to go past october 2nd since if the sept 18 was correct, infant mortality goes up after 2 weeks late. it would just be better to be safe. and if october 4th was correct, the baby would be right on time minus 2 days.

but im still betting on that you ovulated later, and werent really due october 4.



answers from Goldsboro on

I was told in my pregnancy that they "date" the pregnancy based on an early ultrasound, somewhere between 8 and 12 weeks. For me, that meant I was due March 14. However, I measured big on every other ultrasound from there on out. I had 5 or 6 US because I had problems with bleeding. My DS was always 2-4 weeks ahead of where he should have been.
At 36 weeks gestation (based on my last menstrual period), he was measuring out at 40 weeks. I asked if they would induce because by this point I was having problems with pubic symphasis disorder and blood pressure. I had to wait until 38 weeks. At that time, he was estimated to weigh 8.5 lbs. They told me if I went to 40 weeks, he'd weigh 10 lbs. I delivered via c-section after a failed induction at 38 weeks 2 days. My son weighed 7 lbs 12 oz on February 24.
I wish my body would have held out a few more weeks. I did not want a c-section and my son had several problems that I blame on the "early" delivery. He had jaundice and would not latch to nurse properly.
I think as long as you don't go over 42 weeks, they should leave you alone.



answers from Chicago on

Due dates doesn't mean you will have the child on that date. My first 2 came early my 3rd was close to the due date and they set up a back up date 2 weeks later and 4th was late and I was able to choose the date to induce. When you do know the date when the baby is coming, it is a lot easier to plan. Hope that helps. Good luck. I wouldn't worry about it too much. You don't want to have to deliver a larger baby anyway.



answers from Chicago on

I had that thing almost twenty years ago, so just think how modern and updated it is now (all things medical). I am trying to understand why you think they would induce you. Is that your thoughts or did the doctor say that? Most doctors really do want to let baby start on its own unless there is a clear sign that something is amiss, in which case you would want it induced. I'd say be ready the 18th, expect it the 25th and know that if it is further along than that that the doctor knows what she is doing. And in some cases,like my baby was they are just very big babies.

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