Pre-Labour Vaginal Exams: Helpful, or Harmful?
We know that doing a vaginal exam during labour can be used as a helpful tool in some situations, but we also know that dilation is only one piece of the puzzle. There is no way to predict what will happen in the future, and the cervix can’t do that any better than a magic 8 ball can.
But what about pre-labour vaginal exams? Will they help us gaze into the future and predict outcomes?
There is really only one reason for a Care Provider to do a pre-labour vaginal exam, and that is to get a sense of what is happening with the cervix to determine how to start an induction.
No intention of being induced? Okay then. What about to “get a sense of what’s going on”?
Similarly to the cervix being unable to predict the course of a person’s labour, there is no evidence to support that assessing a cervix before labour begins will give a good indication of when it will start, or how long it will last. It is possible to be 2cm dilated and not in labour for quite a while (multiple days/a week). It is also possible to have a cervix that is hard, closed, and posterior in the body, and then spontaneously go into labour that night!
Some potential risks around doing a pre-labour vaginal exam could be:
PROM (Premature Rupture Of Membranes or breaking of the water).
In a study on potentially increasing risk of PROM by doing pre-labour vaginal exams, the findings were:
Without VE: 6% experienced PROM
With pre-labour VE: 18% experienced PROM
Note: it’s possible that a stretch & sweep was also done in this study, either with or without consent.
These exams were done weekly starting at 37 weeks’ gestation.
(Lenihan et al 1984)
What happens when someone’s water breaks before labour is established? Well we know that:
76.5% of people who experience PROM will go into labour on their own within 24h.
90% will go into labour on their own within 48h.
95% will go into labour on their own within 72h. (Pintucci et al 2014)
However, induction is typically offered anywhere in the range of immediately after PROM, to 24h after (this often depends on the Care Provider). If PROM happens, you will need to make a decision about waiting for labour to begin, or choosing induction.
Induction and the risks surrounding it need to be discussed just as much as the reasoning behind offering the induction itself, although it’s typically presented as the “safer option”.
In another study, (McDuffie et al. 1992), the results were very different, stating that there was no real risk in doing pre-labour vaginal exams, but there also weren’t any real benefits.
Sometimes Care Providers will offer a pre-labour exam to check the baby's position. This is not necessary and can be done by palpating the abdomen, (where you at, baby? poke, poke) or by using an ultrasound instead. Reasons for knowing baby positions before labour is established makes the most sense if they are aware of a possible breech (bum down) or transverse (sideways) position. If this is the situation, a confirmation on the baby's position will always be done with an ultrasound.
The Care Provider may find that the baby is in an OP position (facing the birther’s spine with head down). However, evidence suggests that 15-30% of babies will be in this position before labour is established, but only about 5% will stay there throughout labour.
There is a lot of discussion around the OP position creating a more prolonged labour with back pain, and contractions stopping/starting. However, that could be the case regardless of positioning. The truth is, birth isn’t linear so much as a squiggly line, taking you to your end goal, but with lots of natural stalls, starts, and increased and decreased intensity. Is it due to an OP baby? Maybe, but also maybe not…
“The assumed relationship between fetal position and back pain in labour is a dominant discourse, albeit one which is lacking in empirical credibility.” (Lee, Kildea & Stapleton (2015)
I should also note that during labour, birthers who have babies in the OP position will be highly encouraged to get an epidural, but doing so can make it harder for their baby to turn. (Lieberman et al. 2005)
But anyhoo, that’s a bit outside of our current topic.
In general, the official recommendations around vaginal exams even DURING the birth process aren’t necessarily to do them, or even that they improve outcomes. Even in the case of a labour that is “slow” ie progress that is less than 1cm of dilation every 2 hours:
“..slow labours can also be a normal variation of labour progress, and recent evidence suggests that if mother and baby are well, length of labour or cervical dilation alone should not be used to decide whether labour is progressing normally.” (https://www.cochrane.org/CD010088/PREG_routine-vaginal-examinations-labour)
In summary: There is no evidence to support that doing a vaginal exam before labour begins has any benefit whatsoever. There may be even more risks than there are benefits. It seems that one of the primary benefits of this outdated practice is to satisfy the curiosity of the Care Provider. Information relayed to the person receiving the exam can either be encouraging (great position, soft cervix, etc) or discouraging (baby isn’t in a great position, cervix is closed, etc). The latter can be followed up with being told that they will likely have a long and difficult labour because of said position. The risk of hearing discouraging news before heading into your birth might be reason enough not to get an exam. I should also mention that it can be pretty uncomfortable to get one!
I promise you that your baby can and will be born even without the presence of a pre-labour (or during labour) vaginal/cervical exam.
Still want a pre-labour vaginal exam? That is absolutely your choice! But don’t ever feel like you have to consent to something that you don’t want to do.