Post Dates: What Are the Canadian Guidelines?

By Rachel Paterson

December 6, 2019

I became a Mama in 2017, with the birth of my son James. It was soon very clear that even as a health care professional, being a Mama is hard! I struggled with oversupply issues, and a babe who wouldn't sleep for many months. By starting The Mama Coach, I am so happy to be able to support parents through difficult times. We all need some extra help sometimes (me included!); it’s okay to ask for it, and I encourage you to reach out!

First and foremost — what is a post-date pregnancy? The World Health Organization (WHO) and the International Federation of Gynaecology (FIGO) defines a post date pregnancy as a pregnancy that lasts 40+0 weeks plus one or more days. In other words, any pregnancy that goes past the due date is considered a postdate pregnancy. We know that in Canada the number of 41+0 and 42+0 week pregnancies is slowly decreasing.  

Why do we care about a postdate pregnancy?

While the overwhelming majority of postdate pregnancies result in healthy moms and babies, there is evidence of some increased risks at 41+ weeks. Therefore, we need to have a plan in place to reduce as much risk as possible and promote and healthy delivery for both mom and baby.

Tripod of Managing a postdate pregnancy

There are three important factors in managing a postdate pregnancy:

  1. Early in the pregnancy, every woman should have a dating ultrasound to provide an accurate estimation of the due date. This ensures that we are fairly accurate with the expected due date, which means we can make informed decisions in the event of a postdate pregnancy. A dating ultrasound is more accurate at estimating the gestational age of your baby than the date of your last menstrual period, and studies show that a pregnancy dated based on early ultrasound results in a decreased likelihood of a postdate pregnancy (Phew, that’s a mouthful!).
  2. Effective monitoring of fetal well-being. Every woman with a postdate pregnancy should be offered, at minimum, a non-stress test and a measure of amniotic fluid starting at 41+0 weeks. Fetal kick counting is also an appropriate way for Mom to monitor baby from home and potentially have an early indication if something is amiss, although there is limited evidence of this.
  3. Every pregnant woman should be offered a membrane sweep starting at 38 to 41 weeks, and an induction at 41+0 and 42+0 weeks. There are also a whole host of other methods, some with scientific evidence and some anecdotal that are thought to help induce labour near the end of pregnancy, such as acupuncture, evening primrose oil, long walks, spicy food, and sex! 

What does all of this mean?

Your pregnancy is just that — yours! You have the right to make informed decisions based on your wishes and intuition. Whether you choose to have an ultrasound or not, a membrane sweep or not, or an induction or not… the choice is yours. This article is meant to provide you with the information you need to help you make the best decisions you can! If you have any questions or are struggling with your pregnancy, reach out to a Mama Coach in your area to chat. We would be happy to provide support or go through a prenatal class with you to discuss your options. You got this Mama!

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