How Accurate Are Ultrasound Measurements

13 Replies
amanda17 - May 4

I'm probably freaking out a tad much about my due date, so I'm sorry if some of you are sick of hearing about it :P I'm pretty sure I'm due May 30th, but my doctor insists that I'm due June 20th because of my ultrasound measurements. (I had one measurement on March 8th, and another on April 19th both saying I was due June 20th... But my first ultrasound in early December said I was due May 30th) I'm already 3cm dilated and my contractions are getting more intense every day. My doctor gave me pills to stop the contractions but they aren't working. I feel like I'm pretty much ready to go and I'm worried that if the recent ultrasounds were correct, she will come WAY too early. How often are ultrasound measurements that far off and why?

 

Krissy25 - May 4

Amanda, I've always been told that the earliest ultrasounds are the most accurate b/c the further along women get the more the size of the babies vary. For me i had my 1st u/s at 5 week 2 days and my dd, who was just a sac then, measured right on. At 7 weeks she measured 2 days ahead, by 12 weeks she was like 4 days ahead (you get the idea) My last u/s at 36weeks 4 days she measured over 40 weeks!! Thankfully she came early on her own but my doc never changed my due date. Just because babies are bigger doesn't necesserly mean they are ready earlier. For you it seems like the opposite is happening, maybe your baby fell a behind on growth. Have you asked your doctor about the first u/s and why he decided to change the due date just based on measurements? Also is your doctor planning on doing any tests to check the lung development of your baby since he/she might be comming soon? If he is convinced your due date is June 20th i would think he would be concerned with that and possible give you steriods to boost lung dev. if indeed your baby does come early. These are just my opinions and thoughts.

 

kay101 - May 4

They can be about 15% off in either direction. It depends on their equiptment and the ultrasound tech. Has the same person done all your recent ultrasounds? One person could get different measurements than the other. Was she still 3 weeks behind at the one you just had? What are the pills you're taking? Do they have you coming in at all to do NST's?

 

amanda17 - May 4

Krissy - My doctor is completely ignoring my first ultrasound and the dates I've given him that prove me to be due May 30th. He isn't keeping the closest eye on me, my appointments are still two weeks apart and he hasn't talked to me about steroids or what would happen if she was premature...he hasn't really acknowledged it at all except for prescribing me pills. Kay - I've had two different ultrasound techs taking my measurements, they both complained that they were having difficulty getting her measurements because of her position or something like that. She's still measuring behind... the pills are called Nifedipine, I've never heard of it but the pharmacist said it was originally a blood pressure medication, but it can also be used to stop contractions. Anndddd I don't know what NST's are. They aren't really doing any kind of tests on me, the last time I went in all they did was take a urine sample and test my blood pressure.

 

kay101 - May 4

You're taking the same thing I was. How often are you taking them? The max dose is every 6 hours. Do you notice it works better right after you take it then they get worse till your next dose? Because there's Procardia XL (Nifedipine is the generic name for it) that you take every 12 hours and it's time released. It makes your blood pressure drop too so it might make you feel funny, but I adjusted to it after several days. An NST stands for non-stress test. It's where they put the monitors on your belly that monitor your contractions and the baby's heartbeat on a printout, and you press a b___ton when the baby moves. You've probably done one if you've gone to labor and delivery before. Usually when they have you on meds for preterm labor they have you do them at your appointment to keep an eye on how your contractions are doing.

 

amanda17 - May 4

I take them every six hours unless I'm sleeping. The first day I took them my contractions stopped and I always knew when six hours was up because I would immediately get a contraction. The second day I had three contractions during the six hours, then the third day and fourth day (yesterday and today) they don't seem to work at all. The only side effect I've had is pretty bad headaches. I haven't taken a non-stress test before, I've never gone into labor and delivery. My contractions are gradually getting more uncomfortable, but no actual labor.. they've never been less than a half hour apart.

 

ChattyKathy - May 4

Okay, If you are supposed to be due in June then how in the world does your doctor explain an ultrasound that took place when you wouldn't have even been pregnant?! A months difference is a pretty big leap. I can't imagine why they'd be off by THAT much, but many u/s are off by as much as two weeks and they become less accurate the further you go. Personally, i'd go according to LMP. If you don't know it, Go by May 30th.

 

kay101 - May 4

Half an hour apart is actually pretty good, especially since you're probably 36 weeks. Even at 34 weeks it's not bad. The medecine won't stop them completely, it just helps control them. Like without it you might have contractions every ten minutes. If they start becoming regular, like if they come every fifteen minutes, then every ten minutes, then every 5 minutes you would want to go in. Mine liked to jump to 3 minutes apart randomly. With actual labor they'll start coming closer together in a pattern and get stronger. Just in case you do go in in the future the nst has two round circles that are held on your belly with straps. A little graph will print out on the monitor that shows your contractions and the baby's heartbeat. It will tell them how strong and far apart the contractions are, and how well your baby responds to them. They also usually give you a little b___ton to click that will make a mark on the printout each time you feel the baby move. They'll have you do that no matter what you go in for. If you even THINK you might be in labor or that you're having too many contractions or they're too close together, just go in and that's what they'll do. It never hurts to be checked.

 

amanda17 - May 5

Kathy - my first ultrasound was in December, I conceived in September. I would have been 12 weeks according to the June 20th due date. So I would have been pregnant either way. But I got a positive pregnancy test on September 23rd which is five days BEFORE he is suggesting I conceived. That information doesn't seem to bother him either. I'm less concerned about my due date and more concerned about when she's going to be ready to go. I'm really scared of her being premature. Kay - Thanks, do you think I'm high risk for premature labor or am I just worrying too much?

 

kay101 - May 5

Well, your contractions sound like they're doing ok, but the fact you're 3 cm already is a little concerning. Most women start to dialate a lot faster after 4 cm. Don't get me wrong, there are plenty of women who walk around at 3 or 4 centimeters for weeks before they go into labor. You should be ok as long as your contractions stay the way they are now. Remember, I'm probably having my son this afternoon and you're probably 2 days ahead of me. Either way, you're between 34-36 weeks. When I talked to the NICU doctor he said my baby wouldn't have any problems if he was born at 34 weeks, so even if you had her now she'd be ok. At 35 weeks I was told they wouldn't even stop my labor.

 

amanda17 - May 5

Whew! I have been worrying myself to death thinking about all these horror stories. She means everything to me, I just want her to be okay. If that means waiting three more weeks I really don't mind, but if my body wouldn't allow that I wanted to make sure she'd make it.

 

kay101 - May 5

Aw don't read horror stories! She would deffinately make it at this stage. They've had babies live at 22 weeks. At the worst, she might spend a little time in the NICU on oxygen. Not intibated, but like the little tube in their nose that just sits right inside the nostrils you sometimes see old people walking around with that are on oxygen lol I hope you know what I'm talking about because for some reason I can't remember what it's called. Of course she'd be a little small but that's ok. I know your doctor said he'd stop your labor before June 8th, but most will let you go into labor at 36 weeks.

 

krissy2006 - May 5

I am 33 weeks and my doc said that MOST babies are sufficiently mature by 34 weeks to be born and yes, might spend a bit of time in NICU but not for any serious reasons. Just oberservation. My doc told me if I were to go into spontaneous labor at 34 weeks she would not stop it.... so, I think you're perfectly fine!

 

ChattyKathy - May 5

Amanda, my doctor also told me that at 34 weeks, should I go into labor they would not stop it. Most babies (albeit some require additional care) are perfectly fine being born that early. It sounds like you'll have your baby soon, whether the doctor likes it or not! Don't stress about it, try to relax. Your baby will be fine. 37/38 weeks is considered full term anyway.

 

ADD A COMMENT:


You must log in to reply.

Are you New to the forum? Sign Up Here! Already a member? Please login below.

Forgot your password?
Need Help?
New to the forum?

Sign Up Here!


Already a member?
Please login below.





Forgot your password?
Need Help?  
Start A New Discussion