average gestation first time pregnancy
There are articles all over the web that say the average first time mother goes eight days overdue and doesn't have her baby until 41 weeks, 1 day. I say hold off, people. There's only one study that suggested this median: The length of uncomplicated human gestation (Mittendorf et al).onsidering only births resulting from spontaneous labor: 1  The average first time mom had her baby at 39W,5D. 54.9% of first time moms delivered their babies on or before their due date. 2  This is based on 5079 first time moms who filled out the survey.
1 In a twin pregnancy. the average is 37 weeks. for triplets 34 and quadruplets 32 weeks.  The average birth weight for singletons is 7 lbs 7 oz. Average birth weight of twins is 5 lbs 5 oz. for triplets 4lbs and quads 3lbs. A difference in birth weight between multiples is not unusual.