Gestation - Due Date Estimates

Hey fellow Steemers,

I am a soon to be dad with our first child. My wife is in labor at 41 weeks and will most likely deliver tomorrow, so that would put her at 41 weeks + 1 day.

I started reviewing estimated due dates and most often you will be given 40 weeks from the first day of the mothers last period. Where did this come from? Well, it came from Franz Karl Naegele, a German obstratician who lived from 1778 - 1851. You can read more about his rule here:
https://en.m.wikipedia.org/wiki/Naegele%27s_rule

Just from my own asking around it seems that delivery dates are a bit all over the board, most early or late as only about 5% of births occur on the estimated delivery date. Which leads me to believe there must be a better way of estimating and given today's technology you think prediction could be better.

I found this study from Mittendorf R, et al. Obstet Gynecol. 1990. that estimates the due date is 40 weeks + 8 days for "uncomplicated" pregnancies and for cacausian women.
https://www.ncbi.nlm.nih.gov/m/pubmed/2342739/

It would be nice to see some studies done that factor in the women's length of period cycle, age, which number pregnancy, and other possible contributing factors. Not that knowing the due date changes much, but I feel it provides some peace of mind and allows the mom and support system to be ready and prepared.

I wish all that are pregnant and delivering well, may you have safe, uncomplicated and dare I say enjoyable births.

-Steem-surfer