Written by A/Prof Jane Warland
There are a LOT of myths out there about fetal movements. Often it is thought that pregnant women are the only people that can hold to these myths and that maternity care providers know better but this is actually not always the case.
What is the definition of a myth?
a widely held but false belief or idea
Maternity care providers (and sometimes even researchers) often belief the myth that a well fetus will move an average of 10 times in 2 hours. This is dangerous because many care providers will tell a woman who is concerned about her baby’s movements to count to 10 over the next 2 hours and if the baby moves as little as that then all is well.
This advice is given because it is THOUGHT to be based on evidence. I hasten to say that believing this myth is not necessarily the care providers fault because this myth has even made its way into many clinical practice guidelines and once there has become part of circular citing. Circular citing is a pretty common occurrence where a paper has been incorrectly cited once (often by a person or body that appear authoritative) and then others also incorrectly cite it too. This results in a Chinese whisper of sorts that is often really hard to unpick
Most clinical practice guidelines that bother to give a reference for the “evidence” that a well baby will move 10 times in 2 hours refer to an abstract reported by Moore and Piacquadio 1989. Seen in its entirety below
As you can see these authors asked women to record the “elapsed time required to appreciate 10 fetal movements”. The mean time was 20.9 mins, with one Standard deviation being 18.1 minutes. This means that the vast majority of their participants felt their baby move 10 times within a time frame of between 2.8 and 39 minutes. FURTHERMORE, they asked women for whom 2 hours had elapsed WITHOUT 10 movements to report to delivery suite BECAUSE this alarm limit was 5… YES FIVE standard deviations away from the mean (or average) i.e. really really really really really rare !!!!!!!!!!!!!!!!!!!!!!!!
This means that FAR from representing what an average baby does, moving only 10 times in 2 hours is INCREDIBLY rare and therefore VERY likely to represent a baby it HUGE increased risk of stillbirth.
This report of a study, that many clinical guidelines have subsequently cited as evidence of what’s “normal,” has been misquoted, mis-cited, and misinterpreted. If anything this study shows that a normal baby moves ON AVERAGE 10 times in 21 minutes and that IF it takes the mother more than 39 minutes to count to 10 movements then this is well and truly outside most babies ‘normal’ range.
The authors of this commonly cited paper conclude that a “count-to-ten” movement screening program is simple and effective in reducing the fetal mortality rate. NOTE : WHAT THEY DO NOT SAY WHICH IS REALLY REALLY IMPORTANT TO APPRECIATE IS…
Moving 10 times in 2 hours is what the average baby does.
WHAT THIS STUDY ACTUALLY SHOWS IS
IF THE WOMAN DISCOVERS HER NORMAL by counting how long it takes for HER BABY to move 10 times THEN this is an effective way to reduce stillbirth ESPECIALLY IF she is told to report if her baby is moving WAY WAY WAY WAY WAY below the normal level of only 10 movements in 2 hours.
So in sum, if you want to based guidance on this report then please use it correctly and tell women that an average baby moves 10 times in 21 minutes and that even if you have a quiet baby they will probably move at least 10 times in 39 minutes and if your baby is moving as little as 10 times in 2 hours then this is WAY outside the normal range and the mother needs to be immediately assessed NOT reassured.
Better still stop using numbers , hours and counting altogether and simply tell the mum to get to know who her baby is so she can know how her baby is so she can immediately report change and LISTEN to her when she reports concerns!