This week as I was speaking to other doulas online, one mentioned that she no longer uses the term “due date” but has replaced it with “arrival window”. I instantly fell in love with her terminology!
Arrival window accurately portrays the time frame in which a child will be born, and takes the pressure off of a woman feeling that her baby should be born before the due date!
In reality, due dates are a horrible time limit we place on pregnant women. A due date is 40 weeks after a woman’s period begins before she gets pregnant, approximately two weeks before the ovulation that results in pregnancy. Forty weeks is the average length of pregnancy, but averages don’t really mean anything! If you had 3 tall people and 3 short people and averaged their heights, you wouldn’t have an accurate portrayal of any of them. The same is with due dates. Very few women actually give birth on their due dates.
Science shows us that human babies can need up to a 5 weeks difference of gestation time. This information turns our 40 week due date to an arrival window of 37 weeks to 42 weeks.
For decades women have considered themselves full-term at 37 weeks, but with this new research, we can safely argue that a baby who needs the full 42 weeks will not be full-term at 37 weeks. Each pregnancy is different, and each child needs a different, specific amount of time in utero to develop.
The American Congress of Obstetrics and Gynecology (ACOG) has outlined some new definitions to help women understand their due dates. Their new consensus is that 39 weeks is full term, meaning no baby should be born before 39 weeks unless the mother goes into labor on her own before 39 weeks, or if there is true medical need for induction. Thirty-seven weeks is now considered early term, meaning if you go into labor on your own after 37 weeks, no measures will be taken to try and medically stop your labor, and it will not be recorded as a pre-term birth. ACOG states that no elective inductions should occur before 39 weeks, and stresses the importance of only inducing when medically necessary as inductions pose many risks.
For many, the due date is seen as an eviction notice, meaning if the baby isn’t born by 40 weeks then labor must be induced. This is not true. Medical induction is not needed until 42 weeks, which is when a woman is considered post term.
More research is needed, but studies point out that not all embryos implant at the same rate, and that a woman’s age even contributes to how long the fetus needs to develop. While we don’t understand it all, there is ample evidence supporting the arrival window way of thinking.
These new guidelines can be difficult for women who have been using the old guidelines of 37 weeks. Adding another five weeks can seem like a life sentence to a miserable woman who can’t wait to not be pregnant anymore! It will take time to change the social acceptance of 37 weeks being full term, and 40 weeks being the finish line. But with arrival window thinking, women can focus less on dates and more on fetal development and readiness to survive outside the womb.
Be open minded and flexible as you view your due date. All research confirms that the healthiest babies and smoothest births occur when women go into labor on their own. For some of these women, labor will come in the weeks of the late 30s. Others will go several weeks longer. In the long term perspective, a few more days (or weeks!) of pregnancy are well worth the health and safety of your baby and your birth.