Length of Pregnancy Varied by 37 days in Humans (study)
Perhaps it’s not such a great idea to rush to C-section if you are a couple weeks late. This study (link below) certainly helps explain the variability in when a woman may deliver showing that this varied by 37 days in the 125 women studied. It was known in this study exactly when they ovulated, and since ovulation happens mid-cycle, the average 38 weeks and 2 days from ovulation that was found in this study, still corresponds to about 40 weeks from the start of last menstrual period.
The study also showed that older women tended to deliver later, women who themselves had been heavy babies had longer pregnancies and if you have had a longer pregnancy before, you are likely again to have a longer pregnancy. This study points out that it may be preliminary to change how we practice.
I feel this study should reassure those wanting a natural child birth experience, that in the absence of other risk factors or any signs of distress for the unborn child, the rush to C-section if you have not delivered on time may not be the best practice. Check, of course with, your obstetrician or nurse/mid-wife and please do not consider this medical advice- just food for thought.