6. What is the average gestation for each type of multiple pregnancy?

40 weeks is considered a full-term pregnancy; however few higher-order multiple birth pregnancies last a full 40 weeks because the length of pregnancy decreases with each additional baby.

Around 57% of twins and more than 96% of triplets and higher multiples are born preterm. (source #1)

On average most:

  • singleton pregnancies last 39 weeks
  • twin pregnancies last 35.2 weeks
  • triplet pregnancies last 32.0 weeks
  • quadruplets pregnancies last 29.3 weeks (source #2)

According to the MOST Medical Birth Survey, the average gestation for families who contact MOST is approximately:

  • 35.5 weeks for twins
  • 33.1 weeks for triplets
  • 31.3 weeks for quadruplets
  • 29.7 weeks for quintuplets
  • 29.1 weeks for sextuplets

Important note: The numbers above are averages, not goals. Most perinatologists who have extensive experience with higher-order multiple pregnancies agree that your goal is to reach a gestational age of:

  • 37 weeks for twins
  • 35-36 weeks triplets
  • 33-34 weeks for quadruplets and quintuplets
Even if you reach these optimum goals, remember that your babies will still be considered premature and not full-term infants.


Sources:

1. Martin JA, Hamilton BE, Sutton PD, Ventura SJ, Mathews TJ, Kirmeyer S, Osterman MJK. Births: Final data for 2007. National vital statistics reports; vol 58 no XX. Hyattsville, MD: National Center for Health Statistics. 2010. http://www.cdc.gov/nchs/data/nvsr/nvsr58/nvsr58_24.pdf

2. Martin JA, Hamilton BE, Sutton PD, Ventura SJ, et al. Births: Final data for 2006. National vital statistics reports; vol 57 no 7. Hyattsville, MD: National Center for Health Statistics. 2009. http://www.cdc.gov/nchs/data/nvsr/nvsr57/nvsr57_07.pdf

 

Resources

 

Visit the MOST Supertwins Statistics page to learn more about multiple birth gestations.

MOST's online weight calculator estimates infant weight based on gestation and type of multiples.

MOST also offers our book Expecting Multiples: A Comprehensive Guide covering a variety of topics related to pregnancy and delivery of higher-order multiples as well as several other parenting booklets on higher-order multiple births.

Twin Services article "Preventing Premature Multiple Birth"

KidsHealth Week-by-Week Pregnancy Calendar - is a detailed guide to all the changes taking place in your baby and in you! Each week of pregnancy includes a description of your baby's development, as well as an explanation of the changes taking place in your body. You'll also find important medical info that will help keep you and your baby healthy.

BabyCenter's Due Date Calculator (Note: this calculator gives due dates based on singleton pregnancies, but this "original due date" can still be an important piece of information in the management of a higher-order multiple pregnancy.)

Please Note:
MOST provides these FAQs for informational purposes and cautions visitors not to use the content below to make treatment decisions without personally consulting a qualified health care provider. Reuse of this content without proper citation is a violation of copyright. To obtain permission to use Supertwins 101 content contact MOST.

 

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Copyright MOST 2005     Updated 8/16/10