Estimated Delivery Date - Nichols Rule

I recently started to read "Heart and Hands: A Midwife's Guide to Pregnancy and Birth" by Elizabeth Davis. It is more of a book for midwives but the information in it is great for understanding the basics of birth and possible complications.

The point I want to make today is revolutionary to me. Estimated Delivery Date Calculations.

So most go by the Naegele's Rule, or the standard 40 weeks rule. This is LMP - 3 months + 7 days. This does not take into consideration cycle length, or how many births you've had. My first son's due date according to this was September 18, 2010.

12/11 - 3 months = 9/11 + 7 Days = 9/18

The Nichols' Rule is so much more spot on in my opinion.

Here is how to calculate your EDD:

First-time moms with 28 day cycles: LMP + 12 months - 2 months and 14 days = EDD
Second-time moms or more w/ 28 day cycles: LMP + 12 months - 2 months and 18 days = EDD
Cycles longer than 28 days: EDD + (days in cycle -28 days) = EDD
Cycles shorter than 28 days: EDD - (28 days - days in cycle) = EDD

For example: For my first pregnancy my LMP was 12/11/09 and my cycle length was about 30 days. It was my first child.

12/11/09 + 12 months = 12/11/10 - 2 months and 14 days = 9/27/10 + (30-28) = 9/29/10

Actual Date of Birth (Spontaneous) = 09/29/2010 WOW!

And here I thought I had gone 11 days overdue.

So I am using this method this time. According to Nichols' Rule, and taking into consideration that my cycle length is 35 days and this is my second pregnancy, baby # 2 will be due June 15, 2012.

08/26/11 + 12 months = 08/26/12 - 2 months and 18 days = 06/08/12 + (35-28) = 06/15/12

That is almost 2 weeks over the other method (June 2, 2012).

Maybe bad due date calculations are the reason for such a high induction rate and subsequently high c-section rate.

Can I say again WOW!

Photo credit: “Photo by Hilde Vanstraelen / www.biewoef.be”.