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

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

More than 50 percent of twins, more than 90 percent of triplets, and virtually all quadruplets and higher multiples are born preterm (Hoyert, Et al. 2006).

On average most:

  • singleton pregnancies last 39 weeks
  • twin pregnancies last 35 weeks
  • triplet pregnancies last 33 weeks
  • quadruplets pregnancies last 29 weeks (ASRM, 2006).
 

According to the MOST Medical Birth Survey, the average gestation for multiples is approximately:

  • 35 weeks for twins
  • 33 weeks for triplets
  • 31 weeks for quadruplets
  • 29 weeks for quintuplets
  • 29 weeks for sextuplets

American Society for Reproductive Medicine. Multiple Pregnancy and Birth: Twins, Triplets, and Higher Order Multiples: A Guide for Patients. Birmingham AL, 2004, accessed 3/28/08.

Hoyert, D.L., et al. Annual Summary of Vital Statistics: 2004. Pediatrics, volume 117, number 1, January 2006, pages 168-183.

 

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.

For more information on multiple pregnancies, MOST provides a variety of parenting booklets on higher-order multiple births.

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 5/2/08