There’s a lot of emphasis on the magic 40-week mark, more commonly known as the ‘due date’. Surely this must mean something, right? Should my baby be born on this date or by this date? And what does this pressure and expectation do to women anxiously anticipating their baby’s arrival and to the belief they have in their body’s ability to birth?

The truth is, that 40-weeks itself is a rather insignificant date. It is a date which was coined as a rough average, around which time a woman is expected to give birth. Now the focus here is the word ‘around.’ A full-term pregnancy is between 37-42 weeks. So, an ‘overdue’ or ‘post dates’ pregnancy, is that which is post 42-weeks. Many women birth after 40-weeks.

But how accurate are these dates? A scan must give a correct due date right? No. The most accurate time for a scan to estimate gestation is between 10-14 weeks, and even then, it is only accurate to within a week of the true date. Estimating gestation outside of this four-week window is not particularly reliable. If a woman has been having regular periods or is confident of the date of conception, then this can sometimes give a more accurate date than a scan and should be discussed and considered.

There are many important changes happening within the body during these final few weeks and days. Your body, baby and placenta are all working together in harmony to prepare for birth. For each individual this process is different and we should avoid the temptation to compare. This is what we mean when we say that birth will happen when your body and baby are ready.

So, what’s my advice to women preparing to meet their baby? To think of pregnancy as 42-weeks gestation, to cherish the final weeks of your pregnancy and to surround yourself with love.


Rachel Wilson

MAMA Midwife

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