Multiples Multiple Birth Gestation and Birth Weight Data By Pamela Prindle Fierro Updated on September 29, 2020 Medically reviewed by Brian Levine, MD, MS, FACOG Print Juanmonino / Getty Images A report issued by the National Vital Statistics Report in 2018 revealed some interesting data about twins, triplets, and other multiples and how they stack up against singleton births. The numbers make it clear that multiples are born earlier and smaller, weighing less than their singleton counterparts. The Average Birthweight of Twins While the risks for twins are not as elevated as they are for higher-order multiples, twins are still more likely to be born early and weigh less. In the data which was collected from births in the year 2017, 19.51% of twins were born early preterm, (which is defined as prior to 34 weeks) and more than half (59.43%) were born prior to 37 weeks gestation. By comparison, only 9.93% of singletons are born before 37 weeks and 2.76% were born before 34 weeks. Low birth weight is defined as less than 2,500 grams or 5 pounds, 8 ounces. Very low birth weight is defined as weighing less than 1,500 grams or 3 pounds, 5 ounces. Over half of twins (55.39%) met the definition of low birth weight and 9.45% of twins born in 2017 were classified as very low birth weight. The Average Birthweight of Triplets A total of 3,675 babies were part of a triplet birth in 2017. More than ninety percent (98.83%) were born preterm (before 37 weeks) and 67.51% were considered early preterm (born before 34 weeks). Triplets are generally less than half the size of a singleton baby. More than a third of triplets born in 2017 were very low birth weight. The Average Birthweight of Quadruplets Quadruplets, babies born in sets of four, have increased risk. 193 babies were born as quadruplets in 2017. All were born preterm and 91.71% were born early preterm (less than 34 weeks). Similarly, all quadruplets weighed less than five pounds, eight ounces, and 67.91% weighed less than three pounds, five ounces. The Average Birthweight of Quintuplets and Higher Out of the 49 babies born as higher-order multiples like quintuplets, sextuplets, septuplets or octuplets, all were born early preterm (before 34 weeks). All higher-order multiples were low birth weight and 93.88% were very low birth weight in 2017. Gestational Age and Birth Characteristics US Births 2009 All Births Singletons Twins Triplets Quadruplets Quintuplets+ Number 4,130,665 3,987,108 137,217 5,905 333 80 Percent very preterm (<32 wks) 2.0 1.6 11.4 36.8 64.5 95.0 Percent preterm (<37.5 wks) 12.2 10.4 58.8 94.4 98.3 96.3 Mean gestational age (weeks) 38.6 38.7 35.5 31.9 29.5 26.6 Percent Very Low Birth Weight (<1,500 g or 3 lbs. 5 oz.) 1.5 1.1 9.9 35.0 68.1 86.5 Percent low birthweight (<2,500 g or 5 lbs. 8 oz.) 8.2 6.4 56.6 95.1 98.6 94.6 Mean birthweight in grams (and pounds) 3262(7 lbs. 3 oz.) 3296(7 lbs. 4 oz.) 2336(5 lbs. 2 oz.) 1660(3 lbs. 10.5 oz.) 1291(2 lbs. 13.5 oz.) 1002(2 lbs. 3 oz.) 1 Source Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Centers for Disease Control and Prevention. National Vital Statistics Reports. By Pamela Prindle Fierro Pamela Prindle Fierro is the author of several parenting books and the mother of twin girls. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Helpful Report an Error Other Submit By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies