What's My Due Date?

Updated on September 01, 2011
L.G. asks from Glendora, CA
12 answers

I carefully chart my fertility and menstrual cycle so I always know when I ovulate. According to my calculations, my due date is Nov. 14. Based on my LMP, my OB agreed with this due date until an ultra sound was done which moved my due date up to the 4th. I KNOW that due date is wrong because it would mean that I conceived during my period, and I NEVER have intercourse during my period. So here's the problem: I am afraid that when the 4th draws near, my OB is going to start insisting on an induction which I absolutely do not want! Has anyone else out there experienced anything like this?

What can I do next?

  • Add yourAnswer own comment
  • Ask your own question Add Question
  • Join the Mamapedia community Mamapedia
  • as inappropriate
  • this with your friends

More Answers



answers from Augusta on

I am a nurse midwife so deal with this a lot.

You don't mention when your ultrasound was. In the first trimester we don't change due dates unless there is >1 week difference. 2nd Trimester > 2 weeks, 3rd trimester >3. They are less accurate as the pregnancy goes on.

In reality, scans before 12 weeks are considered +/- 2 days, < 20 weeks +/- 5 days, and > 20 weeks +/- 10 days.

So it really depends on when this scan was done how accurate it would be.

You have the right to decline induction, your OB is someone you have hired to perform a service for you, they do not tell you what to do. But consider looking for a provider who will listen to your concerns and not ignore them.

Best of luck.

5 moms found this helpful


answers from Kansas City on

they say that you take the first day of your last period, subtract 7 days then add 9 months. but, i mean there is really no way to know for 100% sure. even if you only had sex on 1 day, you could have gotten pregnant a few days later. and as far as worrying about the doc insisting you be induced, there is nothing to worry about. no doctor can force you to be induced, this isnt a 3rd world country or something. you can say no and wait to go naturally or until you feel like enough is enough already. good luck and congrats on your new baby!!

2 moms found this helpful


answers from Los Angeles on

I say go with an out of hospital birth with a midwife. You'll be happy you at least looked into it. A midwife (not all hospital midwives are any different from their med school-trained counterparts) will absolutely take into account your actual LMP and not rely so heavily on ultrasound scans that can be way off (especially as your due date gets nearer and a baby's estimated weight can be off by as much as +/-2 pounds). An out of hospital midwife has the time and freedom to listen to you and help you plan things, not tell you what to do.

I had an OB during my second pregnancy tell me that my due date was a week later than my LMP showed. After he discounted my potential ability to have a natural birth I fired him. I found a midwife in a birth center and went on to have my perfectly cooked baby at 41 weeks 1 day, birthed her in water as I had always hoped to do, and her gestational age exam showed her to be approximately 41 weeks. Needless to say I don't give ultrasounds all the credit that the OBs seems to give them.

And to anyone who says 10 pounds is too big to birth vaginally, I've seen many babies born who a typical OB would automatically do surgery on because of the baby's weight. Most of the births have been easy for the mothers. And a lot of the ultrasounds will say a baby is over 9 or 10 pounds so mom consents to surgery only to find that the baby is only 6 or 7 pounds and could've been born easily in a normal fashion.

Don't forget about the NICU... babies born too early tend to have breathing and feeding problems.

1 mom found this helpful


answers from Austin on

Show him your data/records.... explain when you think you got pregnant, and hopefully he will listen to you.

At this early point, ultrasounds are usually +/- a week, anyway.

I was sure of the date that I actually got pregnant with my first, and I rarely had a typical 28 day cycle... it was more like 35 days.... so when I went over, I wasn't surprised.... the doctor mentioned possibly inducing me the next week if I didn't go into labor, but I didn't tell him my feeling about the due date.

I think I had read that if you knew the day you conceived, you could actually count days (266/267, I think?), and according to that, I would be due August 18/19 or so....

My daughter was born August 19. (The doctor had thought (according to LMP) the due date would be around August 10....)

1 mom found this helpful


answers from San Diego on

Third trimester ultrasounds are notoriously error-prone; for most measurements etc expect an error margin of 15%. My scans indicated I would have a 10 pound baby and my OB was all "be prepared to have a C-section cuz I doubt you'll be able to push the baby out on your own". I told her: "Let's just make that decision on delivery day" and smiled sweetly. My baby arrived a day short of 38 weeks and only weighed 7.5 lbs.

Your baby will arrive when he or she wants to arrive. As long as your placenta can still sustain your baby and your amniotic fluid is at good levels, there's no reason to induce labor, etc. It is your right to assert your desires for a birth as long as there is no threat to you or your baby.

1 mom found this helpful


answers from Dallas on

An ultrasound's due date is correct by two weeks give or take. So, I'd not agree to having them change it and would insist that you know when you got prego.

My first, I measured two weeks small. They never changed my due date. They went by when I knew I got prego. With my 2nd, he always measured two weeks ahead, but like you, I knew when I got prego. So, they took my word for it, and never changed it. Same story with my next three. I'm currently pregnant with our 5th. For most of the pregnancy, I was only measuring five days ahead. But now at 34 weeks I'm measuring 3 weeks ahead. Still not changing due date. We know when baby was conceived and we're sticking with it.

I've had three different care providers through my pregnancies, and none of them have tried changing my due date. But if they were to ever move my due date sooner, I was prepared to argue it and not agree. It never happened, though. I just didn't want to deal with them telling me my due date had arrived and I was going past time, when I KNEW that I hadn't even gotten to my due date yet. Luckily never been a problem.

I hope the same goes for you! By the way, my son was born on Nov 14:-)

1 mom found this helpful


answers from San Antonio on

My dr said that after 20 weeks, they won't change the due date. So with your situation, you should be fine. The due date will probably change by your next appointment. Or explain to your doctor that conception is impossible on her date unless it was an immaculate conception by God. Why can't doctors listen to us? I told my doctor my conception date exactly b/c I was also good at charting. She didn't listen to me. So now I have a new doctor.

(I did the inducing thing. Not fun. BTW - Noone can force you to induce, but if you choose not to induce, the doctor can refuse to have you as a patient. And finding a new doctor at 38 weeks or whatever is NOT fun. Find a new dr now if you don't like the way this dr treats you or listens to you).

1 mom found this helpful


answers from Los Angeles on

"Due Date" is always considered an estimate and any birth 2 weeks before "due date" or 2 weeks after "due date" is considered "full term"! Irrespective of what your doctor says, you ALWAYS have to give consent for something like an induction. So, no problem, just say "no" if he brings it up! :) Try to relax and enjoy your pregnancy, your baby will be in your arms sooner than you think! Good luck with everything.

1 mom found this helpful


answers from Los Angeles on

Babies can grow faster too. For my first my Due date based on my cycle was May 7. Ultrasounds hovered around the date between May 5 and May 11. On may 9 I had no baby and went in for my check up. We decided to induce the next day. (3 days "overdue") my baby was 9lbs. 7oz on May 10. For my second I didn't really want a 9lb baby. My due date based on my cycle was Nov. 28. After ultrasounds my due date was moved to Nov. 23 and then Nov 14. I had one more ultrasound on Nov. 3. The estimate was that my baby was already 9 lbs. So after my check up on the 5th we decided to induce at night of the 7th. She was born on Nov 8th. weighing 7lbs 12oz. She was perfect size. But if the 7th were her actual due date she would have been conceived a week and a half BEFORE my period.

Ultrasound due dates are based on gestational progress. If you reach your due date (even if Nov. 4) your doc can't induce w/o your consent unless there is an emergency. For my first my doc gave me the option to induce. If I chose not to I would have to go to the hospital every 3 days for a stress test. If I didn't pass they would induce. If I went 2 weeks w/o baby they would induce. I chose to get it over with. For my first I was 25% efaced and to make me feel happy they said 1cm dilated but I really wasn't. For my second I was 0 and 0. Both times I did not feel like delaying the inevitable. My husband has 3 cousins each with 2 kids.2 of the docs let the women wait and they BOTH had to have c-sections because baby would not come and baby was 2 big. (1 sis in law had the same problem). So their senconds both had to be c section cause their docs don't do VBACs.

So do listen to your body. Take into consideration the information your doctor is sharing with you. And make an informed decision.



answers from Los Angeles on

One thing women seem to forget is that we are in control. The OB might want to induce because it works for his/her schedule but not for your body. Just say no. I knew exactly when I conceived, because like you I was very aware. The docs said 9/17 and I said 9/25...darling daughter was born 9/26 at 12:17 am! Unless scans say your baby is 10 pounds, listen to your body.
Congrats on your bundle of joy!



answers from Phoenix on

It doesn't sound like you actually brought up your concerns with your doctor yet? Does your doctor know that you feel the due date is inaccurate?

I recently had a 13 week ultrasound to "date" the pregnancy because I have to have a C section. Their dates were 7 days off from mine. Since I chart, I also felt I "knew" the actual dates. The ultrasound tech told me before 13 weeks, ultrasounds are accurate to within 5 to 7 days. Since my date was within 7 days of theirs, they are going to with mine as the due date.

So, I don't know when you had the ultrasound. If it was early , your date could be pretty accurate and I would fight for it. If your ultrasound was in the second or third trimester where their dating is inaccurate, I would bring this up and fight for your date as well. Heck, some babies like to be born after their due date! They can always monitor you towards the end if they are worried about the baby's health. Fight for what you want or switch.



answers from Los Angeles on

This happens all the time. You know your body better than they do, just hold your ground with the doctors. If they're concerned about the baby when the time comes, then let them monitor fluid levels and heartbeat and everything else. But if there are no real signs of distress, then just let that baby keep cooking! Trust your instinct. :)

For Updates and Special Promotions
Follow Us

Related Questions