Twin Fetal Weight Chart: Estimated Growth Week by Week

A recent study examined how twins grow in the second half of pregnancy. Have a look at twin fetal weight charts week by week.

By Kate Phillipa Clark

The ultrasound-based twin fetal weight charts below are based on a twin study from 2015.  It was published in the American Journal of Obstetrics & Gynecology and adds significantly to the field of fetal growth assessment in twins.

A total of 642 twin fetuses – with a total of 3078 ultrasound observations – were included in the study. Researchers developed a twin fetal weight chart for dichorionic twins in the second half of pregnancy. They also developed a twin fetal weight chart for monochorionic twins.

What does the study show?

The study showed, as expected, that monochorionic twins were consistently smaller than dichorionic twins. It also reaffirmed that twins generally are smaller than singletons.

The study showed twin fetal growth accelerates in the second trimester and continues in a linear pattern in the third trimester until term. This reduction in fetal growth is significant, particularly in the third trimester, compared with singletons.

It concluded that dichorionic twins deviates from singleton reference charts at approximately 32 weeks. Monochorionic twins deviates at 28 weeks. These deviations are one of the reasons why a singleton fetal weight chart shouldn’t be applied to twins.

The normal declaration of growth in twins can seem like an issue, even if it isn’t.

How do I read a twin fetal weight chart?

Fetal growth is better monitored with a doctor.

A twin fetal weight chart shouldn’t be used in isolation without all the other important pregnancy monitoring visits. Also be aware that there’s nothing wrong with your children being below the median weight. 

The median weight is the value for which 50 percent of the fetuses are bigger, and 50 percent are smaller. It  separates the higher half from the lower half.

To give you a better sense of how small or big your babies are, we’ve also included the 10th and 90th percentile.

Average weight of twins at 28 weeks pregnant.

What’s the 10th and 90th percentile?

If your babies estimated weights are equal to or less than the weight indicated as the 10th percentile, it means that your babies are among the smallest 10 percent. 

If your babies estimated weights are equal to or above the weight indicated as the 90th percentile, your babies are among the biggest 10 percent.  

If you’re worried about the growth of your babies, it’s important that you consult your doctor or healthcare provider.

Growth of twins is an important characteristic to be monitored along with other variables like The Fetal Non-Stress test (NST monitoring).

 


Estimated fetal weight in dichorionic twins

Weeks10th percentileMedian fetal weight 90th percentile
22434 grams / 15oz522 grams / 1lbs, 2oz628 grams / 1lbs, 6oz
23508 grams / 1lbs, 1oz
609 grams / 1lbs, 5oz731 grams / 1lbs, 9oz
24587 grams / 1lbs, 4oz702 grams / 1lbs, 8oz840 grams / 1lbs, 13oz
25687 grams / 1lbs, 8oz820 grams / 1lbs, 12oz979 grams /2lbs, 2oz
26790 grams / 1lbs, 11oz941 grams / 2lbs, 1oz1120 grams / 2lbs, 7oz
27894 grams / 1lbs, 15oz1063 grams / 2lbs, 5oz1263 grams / 2lbs, 12oz
281020 grams / 2lbs, 3oz1210 grams / 2lbs, 10oz1435 grams / 3lbs, 2oz
291154 grams / 2lbs, 8oz1367 grams / 3lbs1620 grams / 3lbs, 9oz
301299 grams / 2lbs, 13oz1537 grams / 3lbs, 6oz1819 grams / 4 lbs
311463 grams / 3lbs, 3oz1730 grams / 3lbs, 13oz2046 grams / 4lbs, 8oz
321631 grams / 3lbs, 9oz1929 grams / 4lbs, 4oz2281 grams / 5 lbs
331785 grams / 3lbs, 14oz2110 grams / 4lbs, 10oz2496 grams / 5lbs, 8oz
341944 grams / 4lbs, 4oz2300 grams / 5lbs, 1oz2721 grams / 6 lbs
352100 grams / 4lbs, 10oz2486 grams / 5lbs, 7oz2943 grams / 6lbs, 7oz
362271 grams / 5lbs2691 grams / 5lbs, 14oz3190 grams / 7 lbs
372417 grams / 5lbs, 5oz2869 grams / 6lbs, 5oz3404 grams / 7lbs, 8oz

Estimated fetal weight in monochorionic twins

Weeks10th percentileMedian fetal weight 90th percentile
22437 grams / 15oz508 grams / 1lbs, 1oz590 grams / 1lbs, 4oz
23506 grams / 1lbs, 1oz589 grams / 1lbs, 4oz685 grams / 1lbs, 8oz
24591 grams / 1lbs, 4oz689 grams / 1lbs, 8oz803 grams / 1lbs, 12oz
25681 grams / 1lbs, 8oz795 grams / 1lbs, 12oz929 grams / 2lbs
26776 grams / 1lbs, 11oz908 grams / 2 lbs1062 grams / 2lbs, 5oz
27866 grams / 1lbs, 14oz1015 grams / 2lbs, 3oz1190 grams / 2lbs, 9oz
28989 grams / 2lbs, 2oz1163 grams / 2lbs, 9oz1367 grams / 3lbs
291097 grams / 2lbs, 6oz1293 grams / 2lbs, 13oz1524 grams / 3lbs, 5oz
301251 grams / 2lbs, 12oz1479 grams / 3lbs, 4oz1749 grams / 3lbs, 13oz
311385 grams / 3lbs1642 grams / 3lbs, 9oz1947 grams / 4lbs, 4oz
321531 grams / 3lbs, 6oz1821 grams / 4lbs2166 grams / 4lbs, 12oz
331687 grams / 3lbs, 11oz2014 grams / 4lbs, 7oz2404 grams / 5lbs, 4oz
341823 grams / 4lbs2183 grams / 4lbs, 13oz2614 grams / 5lbs, 12oz
351985 grams / 4lbs, 6oz2386 grams / 5lbs, 4oz2869 grams / 6lbs, 5oz
362123 grams / 4lbs, 10oz2561 grams / 5lbs, 10oz3089 grams / 6lbs, 12oz
372230 grams / 4lbs, 14oz2697 grams / 5lbs, 15oz3261 grams / 7lbs, 3oz
Twin fetal weight chart for twins. Estimated growth week by week
Average weight of twins week by week. See what percentile your littles are in.
About the Author

Kate Phillipa Clark

Kate Phillipa Clark has a bachelor in Journalism and an Executive Master in Corporate Communication. She is an identical twin and so is her father.

8 Comments

  1. Priyanka / 22. February 2019 at 2:15 pm /Reply

    Hello, my wife is 28 yrs and is carrying twins (dcda). She is currently at 30 weeks and both the twins fetel weight & abdominal circumference is not at the expected range for the week. What should she do to improve the weight of each fetus, kindly suggest:

    Fetus A: 1275 GM’s
    Fetus B: 1205 GM’s.

    • Kate Phillipa Clark / 25. February 2019 at 11:36 am /Reply

      Dear Priyanka,

      Congratulations on your wife’s twin pregnancy.

      It’s important that doctors monitor your wife and the babies closely, and that she gets regular ultrasound scans. Her doctor needs to examine whether there could be an issue with the placentas or if your wife could have an infection like rubella or toxoplasmosis (certain medical conditions and anemia can be the cause of babies not growing as expected).
      Assuming that your wife eats a balanced diet, gets the nutrients she needs, and don’t smoke or drink alcohol while pregnant, there isn’t much she can do to influence their weights. But it’s important that she’s monitored by qualified doctors regularly.

      I wish the best for you, your wife and babies.

  2. Das / 22. December 2018 at 5:02 am /Reply

    Hello sir

    My wife is 16 weeks pregnant as on 22-12-2018 , Its a Monochorionic diamniotic twins

    Fetus 1= 152 gm

    fetus 2= 187 gm

    The above weight is normal ?

    • Kate Phillipa Clark / 22. December 2018 at 1:44 pm /Reply

      Hi,

      Thank you for reaching out and congratulations on your wife’s twin pregnancy!

      You should discuss any concerns you have regarding the weights of your babies with a doctor – preferably a Maternal Fetal Medicine (MFM) specialist. The fetal weight charts we’ve published is based on an ultrasound study published in the American Journal of Obstetrics & Gynecology. They didn’t look at weights below 22 weeks. However, I can give you my layman’s opinion. I believe the weights are within the normal range for twins at this point in the pregnancy.

      Have you asked your doctor about the weights? I strongly urge you to seek a doctor’s opinion about this.

      I wish you, your wife and your babies all the best. Please feel free to reply if you have any questions or comments.

      Best,

      Kate Phillipa
      Owner, about-twins.com

  3. Sheetal Tondlekar / 26. July 2018 at 10:01 am /Reply

    hello doctor,
    this is sheetal. i m carrying mcda twins. i m 33 week pregnant with mcda twins. below are the weight of my babies:
    fetal A ( maternal left): 2497 gm
    fetal B (maternal right): 1689 gm
    is it normal.

    • Kate Phillipa Clark / 30. July 2018 at 8:20 am /Reply

      Hi Sheetal,

      Thank you for reaching out.

      Just to clarify: This article was written by me (and was read and approved by one of the researchers who did the study). I’m a Journalist, not a doctor. You should discuss any concerns you have regarding the weights of your babies with a doctor.

      With that in mind, I’ll give you my layman’s opinion. Fetal A seems to be bigger than the median fetal weight for the gestation. Fetal B seems to be among the smallest 10 percent. It worries me that the size discrepancy between the two babies is quite big.
      Have you asked your doctor about this? I strongly urge you to seek a doctor’s opinion about this, preferably a Maternal-Fetal Medicine (MFM) specialist. Is that an option for you?

      I wish you and your babies all the best, and please feel free to get back to me if you have any questions or comments.

      Best,

      Kate
      Owner, about-twins.com

  4. Kate Phillipa Clark / 18. June 2018 at 11:56 am /Reply

    Hi there,

    Congratulations on the addition of twins to your family!

    According to this twin fetal weight chart, you’re babies weights are normal for twins. They are within the median range.

    Some doctors use singleton fetal weight charts for twins as well, and this might be why you’re children are smaller than average according to your doctor’s chart (twins are generally a bit smaller than singletons). You could consider asking your doctor if this could be the case.

    Also, it’s important to be aware of the chorionicity of your twins – meaning whether or not they share a placenta. Twins sharing a placenta needs to be monitored more closely.

  5. Lijith / 15. June 2018 at 4:30 am /Reply

    Hello sir

    My wife is 27 weeks and 4 day pregnant as on 13-06-2018 , Its a TWIN, weight of fetus as follows

    Fetus 1= 1259gm (+/- 184gm)

    fetus 2= 1144 gm(+/- 167gm)

    The above weight is normal ? doctor saying that, the weight of each fetus must be 1500 gm each

Leave a Reply