Twin Fetal Weight Chart: Estimated Growth Week by Week
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.
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
|Weeks||10th percentile||Median fetal weight||90th percentile|
|22||434 grams / 15oz||522 grams / 1lbs, 2oz||628 grams / 1lbs, 6oz|
|23||508 grams / 1lbs, 1oz||609 grams / 1lbs, 5oz||731 grams / 1lbs, 9oz|
|24||587 grams / 1lbs, 4oz||702 grams / 1lbs, 8oz||840 grams / 1lbs, 13oz|
|25||687 grams / 1lbs, 8oz||820 grams / 1lbs, 12oz||979 grams /2lbs, 2oz|
|26||790 grams / 1lbs, 11oz||941 grams / 2lbs, 1oz||1120 grams / 2lbs, 7oz|
|27||894 grams / 1lbs, 15oz||1063 grams / 2lbs, 5oz||1263 grams / 2lbs, 12oz|
|28||1020 grams / 2lbs, 3oz||1210 grams / 2lbs, 10oz||1435 grams / 3lbs, 2oz|
|29||1154 grams / 2lbs, 8oz||1367 grams / 3lbs||1620 grams / 3lbs, 9oz|
|30||1299 grams / 2lbs, 13oz||1537 grams / 3lbs, 6oz||1819 grams / 4 lbs|
|31||1463 grams / 3lbs, 3oz||1730 grams / 3lbs, 13oz||2046 grams / 4lbs, 8oz|
|32||1631 grams / 3lbs, 9oz||1929 grams / 4lbs, 4oz||2281 grams / 5 lbs|
|33||1785 grams / 3lbs, 14oz||2110 grams / 4lbs, 10oz||2496 grams / 5lbs, 8oz|
|34||1944 grams / 4lbs, 4oz||2300 grams / 5lbs, 1oz||2721 grams / 6 lbs|
|35||2100 grams / 4lbs, 10oz||2486 grams / 5lbs, 7oz||2943 grams / 6lbs, 7oz|
|36||2271 grams / 5lbs||2691 grams / 5lbs, 14oz||3190 grams / 7 lbs|
|37||2417 grams / 5lbs, 5oz||2869 grams / 6lbs, 5oz||3404 grams / 7lbs, 8oz|
Estimated fetal weight in monochorionic twins
|Weeks||10th percentile||Median fetal weight||90th percentile|
|22||437 grams / 15oz||508 grams / 1lbs, 1oz||590 grams / 1lbs, 4oz|
|23||506 grams / 1lbs, 1oz||589 grams / 1lbs, 4oz||685 grams / 1lbs, 8oz|
|24||591 grams / 1lbs, 4oz||689 grams / 1lbs, 8oz||803 grams / 1lbs, 12oz|
|25||681 grams / 1lbs, 8oz||795 grams / 1lbs, 12oz||929 grams / 2lbs|
|26||776 grams / 1lbs, 11oz||908 grams / 2 lbs||1062 grams / 2lbs, 5oz|
|27||866 grams / 1lbs, 14oz||1015 grams / 2lbs, 3oz||1190 grams / 2lbs, 9oz|
|28||989 grams / 2lbs, 2oz||1163 grams / 2lbs, 9oz||1367 grams / 3lbs|
|29||1097 grams / 2lbs, 6oz||1293 grams / 2lbs, 13oz||1524 grams / 3lbs, 5oz|
|30||1251 grams / 2lbs, 12oz||1479 grams / 3lbs, 4oz||1749 grams / 3lbs, 13oz|
|31||1385 grams / 3lbs||1642 grams / 3lbs, 9oz||1947 grams / 4lbs, 4oz|
|32||1531 grams / 3lbs, 6oz||1821 grams / 4lbs||2166 grams / 4lbs, 12oz|
|33||1687 grams / 3lbs, 11oz||2014 grams / 4lbs, 7oz||2404 grams / 5lbs, 4oz|
|34||1823 grams / 4lbs||2183 grams / 4lbs, 13oz||2614 grams / 5lbs, 12oz|
|35||1985 grams / 4lbs, 6oz||2386 grams / 5lbs, 4oz||2869 grams / 6lbs, 5oz|
|36||2123 grams / 4lbs, 10oz||2561 grams / 5lbs, 10oz||3089 grams / 6lbs, 12oz|
|37||2230 grams / 4lbs, 14oz||2697 grams / 5lbs, 15oz||3261 grams / 7lbs, 3oz|
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.
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.
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 ?
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.
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.
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.
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.
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