how accurate is an ultrasound later in pregnancy?

[betty12]

so im very confused as to when im due and so are my doctors......my baby is or looks like is measuring big so they have had me do alot of diffrent u/s to check and see if he is big or not or if im further along. well about 3wks ago according to the u/s tech my baby was measuring 35wks and 2days so they changed my due date from 10/16/08 to 9/14/08 then at my last doc apt my doc measured my belly and she said my belly was 33in or so and i was thinking well since the doc changed  my due date to 9/14 then im about 36wks and a few days but my doc seemed concered and sent me to get another u/s scan and the doc there told me that he cant really determine when the due date is through an u/s later in pregnancy cuz it could be off by 2 or 3wks but he said it looked more like i was 35wks now instead of 38 that i was told 3wks ago...so which do you think is more acccurate??? did he mean the u/s could be 2 or 3wks ahead or behind? so im still confused as to when im due...my lmp was 1/10 and that would go right with due date 10/16 but since the baby was "big" they wanted to change it...

[CYW]

my friend didn't have a lmp...her lmp was dec07....she found out around march she was pregnant.. her dr would not send her for an ultrasound..which i find confusing...anyways as the first she had around 4 weeks pregnant they said she was approx 4 weeks(I thought you don't really see that early but anyways).. anywho, she had her routine U/S when she was supposed to be 16 weeks and the baby was measuring 19 weeks 4 days...i told her later are innaccurate...if it were my baby i would be VERY worried because if they wanted to induce and the baby is born(but testing the placenta they would know the babys age i believe...anyways, as i said if it were my baby i would be worried...but she acts like nothing is wrong and the ultrasound is all right etc....

I think by what you are describing your lmp it is pretty accurate...Good luck

[kelliestarr]

Your due date is Oct 16.

[mog__x]

Ooh i'm sorry. My placenta brain caused me to misread your post. Please ignore my last reply. I hope you get it sorted soon. =]

[mog__x]

You said your LMP was 1/10? Mine was also then and I am not due until 19th October. So have you mixed your dates up somewhere? Just a possibility. =] I hope you figure it out soon.

[alaysha]

Always go by the early ultrasound due date. All babies develop at the same rate until 13 weeks and then each will develop at their own rate. Some weeks they may be measuring bigger than other weeks and others smaller. During my pregnancy Aspen was ahead and then she was measuring behind and she was just fine. If you are concern though ask your doctor to check for lung maturity and if he is measuring big and your doctor is concerned than get induced. Hope this helps some.

[betty12]

this is something i will deff be talking to my doc about at my next apt this coming thurs. i have also heard that after 41wks your placenta dosent function the same way anymore i think its called an "aged placenta" or something and i really wouldnt want anything to happen. i mean really who does?!

[ziggysgrl0724]

I dont agree...the conditions inside a uterus can go downhill quickly for a baby if left inside too long past the due date....a placenta is not meant to last and eventually starts to break down...not to mention mecomium and other things....I would say the biggest thing is that the incidence of stillborn is double after 42 weeks then it is at 40...they are not sure why but it may have to do ith the fact that the placenta stops functioning as well as it does at 40 weeks......that would be reason enough for me to not want to just sit around and wait.

[BTS1022]

The way I look at it....because im sooooo tired of not having a decently guessed due date. My docs keep going back and forth from Oct 14th to the 24th. I have no idea when I Ovulated because I was on Depo for 2 yrs straight. I never even had a period, so the pregnancy was a huge surprise.

Anyways- I refuse to go by a *due date* my due date is whenever my baby decides to come. Wether it be on the 14th....24th......or the 3rd of nov, aslong as he is nice and healthy inside, he can stay in until he is ready.

I know I would hate to be told that I was 38/39 weeks preggers...go over due to 42 weeks, get induced and POOF have a premature baby....Your body will always go naturally even if your 43 weeks preggers, eventually your body will make you go into labor....I dont see induction as something that is medically needed.

[ziggysgrl0724]

I completely understand your concern with your baby being left inside too long because they can't figure out whats going on.  This is something I would SERIOUSLY address with your dr.  Ask him how he can guarentee the safety of your baby without knowing exactly when he is due.  perhaps the best thing for you to do is when the Sept. due date rolls around, ask for an amnio to check for lung maturity...if lungs arent mature its not time yet, and maybe he is just a big baby.....but if his luings are mature tand he is a full sized baby he would probably be ready to come out.,

[nutz19]

yes i would go by your original due date. I'm measuring 2 weeks ahead but i still go by my due date 12/10 at least then if he/she comes early it'll be a surprise. hugs and kisses

[mj_mommy_manda]

I would go by your last period.. There could be a chance that you also "had a period" while you were pregnant, (that happened to me.. Well at least I thought it was a period.) but then we went by the period BEFORE the "fake period" and the date of my actual LMP and the size the baby was meausuring at 13 weeks were exactly on.. Try not to stress about it too much, your doctor will probably monitor him closely.  They can tell how mature the lungs are by ultrasound now I think so that is probably something your doctor will monitor as that is usually the last thing to mature.. Good luck!

[betty12]

at my very 1st u/s the doc said going by my lmp which was 1/10 it looks like very very accurate to be 10/16/08... and thats when i was like 8wks he has a u/s machine at the office and he did a vaginal u/s. then everytime i went to the doc every 4wks he wouldnt mention anything about the size until i was like 24wks and went in he said the baby was measuring 28wks instead but didint change anything so when i went back agian thats when he sent me to a profesional u.s tech person and that person said big too i was to be 31wks and was 35wks. im just worried that if i never dialate on my own and the baby is in there for longer than 41wks cuz no one knows my due date if it is sept or oct that something serious will happen to him.

[betty12]

thank you everyone i will just say 10/16 for now since ill be going by my lmp and oh well if i have a big baby at least he will be a healthy one.lol if hes to big for me to deliver normally guess ill be having a c-section but then again yo never no. i dont think hes big really cuz the u/s tech sayed he looked 5lbs 9 oz as of now but that can also be off by a 1lb or 2 so idk. and my stomach is big for my size but thats cuz i was small to begin with im 5"2" and weight 108lbs before pregnant and yeah ive gained alot of weight but its all in my belly i think. ill post a newer pic up in a bit n-e ways i now weigh 145lbs yikes i no!

[Wendy80]

I agree with mj_mommy... you should really just go with the initial due date they gave you (usually based on your lmp and the very first ultrasound).  It'll just be easier for you since your doctor's can't seem to make up their mind.  From my own personal experience, my doctor told me when I was around 28 weeks that it looked like I was measuring ahead, but even so, they wanted me to keep my initial due date b/c that would always be the most accurate one (and the reason it appeared that I was mearsuring ahead was b/c my baby was much bigger than the "average" baby for that particular time period... and continued that way for the following 8 weeks until it appeared she finally slowed down a bit).  It would appear all of that measuring is sort of guess-work anyway... but in terms of accuracy, I'd go with 10/16 for now.

[JoyRenee]

The reason it's difficult is because babies grow at different rates. Some people are naturally bigger than others and vice versa. Same thing with babies...

Also, measuring fundal height is NOT always accurate because some women have long torsos (therefore their uterus may measure smaller than it should) and others have really short torsos (like ME and I always measured ahead). And everyone's belly is different shapes and sizes.

Your due date should be based on your LMP, or if your doc is concerned about birthing a larger baby, then get induced as soon as it is deemed safe.

[mj_mommy_manda]

betty- when was your first ultrasound? how far along were you? you should most likely go by that date.  at my first (13 weeks) my due date was October 29.  My second (21 weeks) my due date was November 6, and now at my last one it would be October 31.  Babies grow at different rates.  The fact that your baby is big shouldn't affect your due date because a "big" baby needs just as much time to develop as a "normal" or "small" baby.  I would go by the due date of your earliest ultrasound.  Early ultrasounds are most accurate.

[#1 girl]

no, they would have stayed in a month longer....
My 1st I was a week late with and only started labor because my Dr. stripped my membrains.
My second I had a section 6 days before due date and he was 9.4 lbs, he never dropped and I never dialated, he would have stayed in longer too

[betty12]

so you had your babies early??? did you have any complications causing them to come a month early???

[#1 girl]

I believe the most accurate U/S is giving in the beginning.  I had 2 big babies who would have stayed in me a month longer if they could have.  Some people just happen to have big babies, and it does not mean that your due date is wrong.

[betty12]

yeah i know im just very confused and iam also going crazy not knowing what is going to happen....im just ready for it all to happen at anytime since i dont really know when im due.lol i know it sounds kinda rediculous when people ask me oh when are you due and i reply um i dont really know it just sounds dumb.lol

[krissyy]

i have no idea how that works.  i was told that i was measuring "the small end of normal."  my lmp was nov.19 and i am due sept. 5 (but i have a 40day cycle).  i conceived my baby on dec.15, and i am positive about that because we were moving and that was the only day we bded.  if i were you, i'd just be prepared to go at any time.  i know that is easier said than done because i am sure that you want more of an idea of when you are going.  i know i'm going crazy not knowing when it's going to happen!!  hopefully someone else will have a better answer for you.  good luck!!