Are Vaginal Exams Accurate?

"When we interrupt a labouring woman to poke her cervix we interrupt labour."

Are Vaginal Exams Accurate?

If there was one part of pregnancy that women found unpleasant but unavoidable, it would probably be the vaginal exam assessing cervical dilation. It has come to be a mainstay of modern maternity care, but in actual fact the routine assessment of cervical dilation, is not an exact science.

We have come to believe that vaginal exams are imperative because they tell us how labour is progressing and we equate health with progress. However cervical dilation tells us one thing and one thing alone. It tells us how dilated the  cervix is in that instant.

But wait a minute! Does it really tell us exactly how dilated the cervix is?

NO!

One of the main problems with vaginal exams is that different care providers can check the same cervix and make different estimates. Two fingers in a vagina do not provide a precision perfect measurement.

Let’s do a little experiment.

AIM: To assess how accurately multiple people gauge measurements and whether their estimates are identical.

METHOD:

  1. Get a ruler and have several people feel how long 1cm – 10cm is.
  2. Ask them to memorise how each length feels.
  3. Find some familiar household objects that are between 1cm and 10cm                                                  
  4. Blindfold everyone and see how many can guess the correct length of familiar objects, using only two fingers.

OBSERVE: Does everyone guess the same length for each object? How many people’s fingers naturally stretch to 10cm? 

Someone might make the point that care providers spend many years feeling and measuring cervixes, so they are better at it, and that might well be true. But as we can see from our experiment, different people make different estimations of the same familiar object, and it’s well known that care providers make different estimates, and are frequently inaccurate as well.

Why do we believe that vaginal exams are so exact? We believe it because we are raised to see doctors and the practice of medicine as an exact science. However, there’s an important difference between the two.

  • A scientist has to work from the premise that they don’t know what is happening, how or why it happens, and they must prove beyond doubt that they are right about any theories they form, or discoveries they make. In order for their work to be respected, it needs to be reviewed by their peers.
  • A doctor must assume that they are always right. The decisions and recommendations they make, are quite literally the difference between life and death. So doctors have to assume that they are right or they will be frozen and incapable of decisive action. They do not always have the luxury of peer review because often, time is short.

So when we look at it in this light we can see that the practice of medicine and science are quite different, and our assumptions about medical practice are skewed by our unwavering deference to “experts”.

Michael Rosenthal OBGYN famously remarked that:

“The first intervention in birth that a healthy woman takes is when she walks out the front door of her home in labor, from that first intervention, all others will follow.”

If he is right that the first intervention is leaving the comfort of home, then it makes sense that the second intervention is the vaginal exam upon admission to the hospital. The interventions that follow include synthetic hormones to increase the intensity of labour, and major surgery if the woman’s cervix is not dilating at a set pace.

When we interrupt a labouring woman to poke her cervix we interrupt labour. Think of how a vet might attend the birth of an endangered species, an elephant for example. Can you imagine a vet waltzing into the pen where the mother elephant is labouring and sticking their entire arm into her vagina to assess dilation? Of course not, that would disturb her. We all know that disturbing a labouring animal is dangerous.

But surely if cervical dilation is such an invaluable measurement, when the survival of an entire species depends upon the birth of one elephant calf, the vet should monitor labour closely!

Vets DO monitor labour closely. Very closely. They just do it very differently to doctors. Vets monitor the behaviour of the mother to be, and go out of their way to avoid disturbances. They know that disturbing her might cause complications. Vets use medical intervention as the last resort, not as if the birth will only be normal if each elephant gives birth exactly the same way.

Before consenting to or declining vaginal exams it’s important to understand that they have other uses. A vaginal exam can give a care provider information about the position a baby is entering the pelvis and how deeply in the pelvis the baby is. Vaginal exams can be helpful, but only in conjunction with other health information.

Cervical dilation is not the yardstick of health in labour, and surely there’s a limit to how many times we need to assess these things. The routine use of inexact vaginal exams is not saving lives, it is making women uncomfortable, and causing unnecessary intervention. In fact routinely giving women vaginal exams is, in itself intervening unnecessarily. We need to focus on health, and only check dilation if health suggests that there may be some benefit in the interruption of labour.

WW Discourse - Have your say!