The average duration of pregnancy decreases as the plurality of births increases. The average gestational period for singletons was 38.7 weeks in 2005. However, the average gestational period was only 35.2 weeks for twins, 31.9 weeks for triplets, 29.8 weeks for quadruplets, and just 27.4 weeks for quintuplets and higher.
The average duration of pregnancy decreases as the plurality of births increases. The average gestational period for singletons was 38.7 weeks in 2005. However, the average gestational period was only 35.2 weeks for twins, 31.9 weeks for triplets, 29.8 weeks for quadruplets, and just 27.4 weeks for quintuplets and higher.