24 Weeks Measuring at 20 Weeks, Should I Worry?

Updated on December 29, 2009
S.G. asks from Fort Collins, CO
13 answers

I am currently 24 weeks pregnant with my 2nd child. We had an ultrasound done at 20 weeks and the baby measured perfectly normal. At my doctor's appt today, she said that my uterus was measuring between 20 and 21 weeks. She wants me to have another ultrasound done to make sure things are okay. I am feeling the baby moving quite a bit My first daughter was born just over 8 pounds, so I don't think I'm just prone to having small babies like the doctor suggested. Have any of you measured smaller than you should have and what were the results? I'm trying to be optimistic, but am also kind of worried.

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answers from Pocatello on

Your probably just fine. I am a small woman and don't get very big when I am pregnant. I always measure a couple weeks less than what I really am. Like when was 25 weeks I measured about 22 weeks. And my babies are fine. my tummy just doesn't get that large. People can never believe how far along I am when I'm pregnant cause I never look very big. So it's good to get it checked out but I bet all is well.



answers from Salt Lake City on

Had 5 babies weighing between 6.2 and 7.8 all came AFTER their due date. I measured small for all of them. Had additional ultrasounds almost every time as the new midwifes I was seeing didn't know my past. (Delivered by 5 different women due to moving). They alwaysgot me all worried as well but everything always turned out great. They are doing their job to just check it out. Also, if you are tall, this is common. People always told me I was so small and after awhile, it wasn't a compliment, I started to worry. I look about 6 months pregnant at 9 due to my height 5'10 and all the room for the baby to hide in. I am sure it will be fine!



answers from Grand Junction on

I "measured small" with both of my pregnancies and my kids were 8.13 and 8.4. Doctors don't know everything!



answers from Boise on

The same sort of thing happened to me, except I was measuring big. I wasn't concerned because my first 2 babies were ~9 pounds. But I wasn't going to turn down another ultrasound, ya know? BTW, I was seeing a different person that day because my doctor was in surgery.
During the u/s, the baby wasn't measuring big at all. In fact, he was only 75 percentile. I thought that odd since my other babies measured bigger.
Then just a few weeks later, I was measuring a week or two small. My doctor wasn't concerned, although I was a bit confused.

Turned out my baby was only 7 lbs 7 oz! He was tall (22 inches) and skinny and not at all what we expected. But he's perfectly healthy.

When I was trying to figure out what was going on with the measurements, I realized that when they measure us, they're using centimeters to measure something that's soft and round and internal. Talk about a fudge factor! Take another look at a ruler and see how tiny a centimeter is! I think it's a bit ridiculous, when you think about it, that they order tests when there's only 2 cm difference between what they measured and what they think they should have measured. As if they could possibly measure that accurately!

So I'm sure your baby's fine. Enjoy the extra ultrasound!



answers from Provo on

It's just like the percentiles at your pediatrician: Head 75th Percentile, Weight 50th percentile, Length 29th. It's just numbers and is not an indicator of who will get into college and whether or not you'll be a good mom. You're body knows what it's doing and will expand overnight. Its usually the day YOU weren't thinking of it, but suddenly everyone says, "WOW! You got big!".

Hang in there, and don't lose sleep over somone else's numbers. There's so many other things to worry about. Like what you're gonna wear at 41 weeks. ;D



answers from Provo on

Fundal height measuring small does not necessarily equal baby measuring small. While measuring to the top of your uterus is a generally reliable thing (which is why docs still do it), your baby's position can change how it measures. If baby happens to be stretching out and sitting high when the dr measures you, you can measure ahead. If baby happens to be all curled up and sitting far back into you that day, you can measure behind. If you consistently measure a number of weeks behind, or aren't continuing to have consistent growth, then it can indicate a problem, but a measurement being off one time is very rarely cause for any concern. Ultrasound measurements of baby's growth at this point in pregnancy are going to be much more reliable indication of how things are proceeding at this point.
I measured small for the last 8wks of my last pregnancy, and that baby popped out at the same size of most of her siblings-even the baby where I measured a bit big for a while.
But hey, getting another peek at your baby is never a bad thing! :)


answers from Dallas on

First of all congrats on the pregnancy!! Do you smoke? That could a small measuring baby......are you gaining weight? i was measuring small but only about a week smaller.....When do you go for your next ultrasound?


answers from Reno on

oh I wouldn't worry.. some people just have small babies. The measurements are based on averages not a hard and fast rule. As long as there's movement and you're healthy I'm sure all is well. I'd do the ultrasound just to be on the super safe side, but don't get frantic... my little guy measured small the whole time and he's just fine. All the babies in my family are just tiny because we're tiny ( I'm 5'2" and normally 125 pounds and I'm the biggest person in my family)



answers from Denver on

My daughter was measuring quite large at both a 20 and 26 week ultrasound, so much so they wanted to change my dates. She turned out one day past my due date 6lb 15 oz; all babies grow at different rates, even in utero! Have your ultrasound to make sure everything looks fine, but don't stress too much before hand (stress is not good for you or the baby). Go with your gut until they can conclusively tell you something different!



answers from Provo on

I just had my second baby 2 weeks ago and towards the end of the pregnancy I kept measuring behind by a centimeter or two. That wasn't quite as much as your's, but I didn't worry about it. When Ely arrived, he turned out to be a nice 8 lbs even, 14 oz bigger than my first baby! I wouldn't worry too much (if you can help it) until you get the other ultrasound and see what it says. Good luck!



answers from Denver on

I would wait for the 2 ultrasound. I never measured right with any of my pregnancies--all 3 of mine were tiny, but all delivered on time-- none over 7 pounds. I do know of a several people whose 2nd babies were smaller than their first, my ob told me that it is actually more normal than people think. I am sure your 2nd us will show a healthy little one:)


answers from Denver on

I had a 7 lb firstborn and a 4 lb secondborn. The second started to measure low at around that time, maybe a little sooner. And by "measure", I don't mean tape measure (there is a lot of error, as you can imagine, in a tape measure). I mean a real ultrasound measurement done by a qualified specialist, where they measure the head and 4 or 5 other things to get more accuracy. The specialist, through ultrasound, discovered that I had one uterine artery that wasn't functioning properly; the baby wasn't getting everything he needed from the placenta. He measured small throughout and I was considered at a very high risk and was even hospitalized once. I received a couple of steroid shots to be safe, in case he was born early. I went into labor at 35 weeks and he was born healthy with his lungs fully developed. Small, but healthy. It all turned out in the end, but it was very stressful. I don't think I would have made it if it were not for the specialist that I was seeing 1-2x/week (plus the non-stress tests!). My regular OB is awesome but they just don't have the technical expertise to read the ultrasounds the way the specialist can.



answers from Fort Collins on

I remember with atleast one of my pregnancies measuring one or maybe two weeks off at one point. The doctor at the time explained it as the baby being in a different position. However, that was a measurement done on the outside of my tummy from top to bottom not ultrasound. Sorry for your worry. Remain optimistic and have another US done to be sure. Much luck to you!

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