This is a big one and I think really important to talk about and look at the evidence, risks/benefits of cervical checks in the third trimester. It’s also important to know your rights, and to be familiar with your own comfort level when things like cervical checks are offered – this one is a bit different than most of the topics I’ve covered in this series because the evidence doesn’t necessarily support a need for it at all times (see below). So lets dive in (Paw Patrol, anyone?).
As a note: you should always discuss these things with your healthcare provider, as they may have rationale for offering or suggesting a cervical check that is particular to your unique situation. Discuss, ask questions and make an informed choice.
Disclaimer: this blog is not medical advice. This blog is for informational purposes only. Please direct your medical questions to your trusted healthcare provider.
Now, before we get started – Evidence Based Birth has a great video on this topic from 2017. Here is the link to that page which includes both the video and the transcript (depending on your preference).
What are cervical checks?
I mean, you probably know what a cervical check is (or maybe you don’t which is also fine!) – it’s exactly what it sounds like. Your provider would be checking your cervix. In pregnancy or labor, this would be to see progress or dilation, and other changes in the cervix. They also can use a check to assess baby’s position. Does dilation really tell you anything with surety? I’m sure you’ve heard stories from many women who have had checks and are told they’re like 4 cm dilated but then don’t go into labor for some time! So – perhaps yes and no. We will explore that more below in the risks & current evidence section.
Here is a video talking about a vaginal exam (cervical check) for dilation done by a doula, if you’re unfamiliar.
Risks of Cervical Checks & Current Evidence
I will start out by saying, like with many topics in reproductive health for women, it is very difficult to find reliable information on this topic – especially online. I already provided the EBB link above which is probably the most useful – however there are a few new sources discussing pelvic exams (mostly in general, but the information remains relevant in pregnancy). So to avoid repetition, I will quickly summarize the findings on the EBB page based primarily on two older studies, then I will look at some newer sources as well.
Firstly, are there benefits to the cervical exam? What can it tell us?
As I mentioned before, they are often used in pregnancy to examine dilation and effacement. If you’re not familiar with those terms (or what they mean/how they are different, because it can be confusing), dilation is the cervix opening (think the photo that goes viral often of the different foods compared to dilation centimetres) and effacement is the cervix thinning out. You can find a good image and description here.
As I also mentioned – whether or not this information means very much is questioned. At the very least, EBB says it satisfies curiosity – which I can say from experience is true. The one time EBB mentions it being useful – and again, from experience I can concur – is if you are going for an induction and need to assess dilation, which can help in the decision as to what type of induction method to pursue and help decide if induction is a good choice.
They can also be used to check fetal positioning, however EBB notes that this can be done other ways making a cervical check for this purpose unnecessary.
So, in short: other than for inductions, the purpose of the cervical check during pregnancy or labor is questionable in the current day when we have access to things like ultrasound to help with assessments. Again – there may be particular situations where your provider does think a check is necessary, and you should be given an opportunity to discuss this or ask questions. A cervical check should never be done without your consent.
What do the older studies say?
The study referenced by EBB from 1984 found that PROM (prelabor or premature rupture of membranes) – when your water breaks prior to contractions starting, which is what happened to me with my daughter – risk increased with weekly cervical checks in pregnancy.
The study from 1994 referenced by EBB found that there was no benefit to frequent or weekly cervical checks, but also no particular harm. EBB explains the conflicting results of these two studies by suggesting that the 1984 study may have included membrane sweeps, which are known to increase risk for PROM.
There may be a benefit to a cervical check – but it would be when it is determined to be necessary, or for induction purposes. Cervical checks without rationale (unnecessary) are not considered beneficial based on current evidence.
Is there any other information out there?
Minimal. Pelvic exams in general are certainly debated in the literature and by providers in regards to their necessity in different situations, including at different times in pregnancy.
Most studies I could find looked at pelvic exams in first trimester of pregnancy only.
I did find one large and recent study on the risk of chorioamnioitis in relation to cervical exams during full term labor – and the study did find that there is an increased risk of infection. The authors suggest only using cervical examinations when necessary during labor, to reduce risks. But what is “when necessary”, is what I’d like to know.
Another study I read from 2009 found that ultrasound may be a good alternative for assessing fetal positioning and station (engagement). Ideally then – cervical checks in pregnancy should be minimized (again barring any particularly unique circumstances, or if the pregnant person wishes to know how dilated they are, etc).
Beyond that, I could not find much more recent research on the topic (but please share if you’re aware of some).
**I would mention that one obvious risk of cervical exams is that they can be uncomfortable or may be traumatic for pregnant or birthing people. This wasn’t really captured in the studies and data, but it is certainly something that is reported by many women and warrants more consideration.**
The verdict then on risk vs benefit is harder to determine, because of the lack of evidence.
Based on the older two studies, both risk and benefit seem to be minimal if checks are done unnecessarily. However, the more recent 2021 study points to a risk for infection in association with cervical checks during labor. At this time, it’s generally recommended to avoid unnecessary cervical checks while in labor – however, whether or not the check is necessary is something that would be assessed by the maternal care provider on each case. Necessity could also be debatable and differing between providers. It should be a discussion with the patient and never done without consent, that much is for sure. I would also love to see some sort of hard guidelines as to necessity – but I simultaneously recognize that critical thought is a part of medicine and nursing care, so the term could be variable and ever-changing. Sigh.
I’d like to take a moment to remind you that you always have the option to decline – anything really, but in this particular situation I am of course, referring to cervical checks during pregnancy or labor. You may wish to decline checks because, based on evidence, you don’t find them necessary or you are concerned for infection risks. Or – you may choose to decline them because you are not comfortable with them. Or – you may want to decline them during pregnancy because hearing how dilated you are may just cause you to become anxious, impatient or frustrated.
It is your body and you certainly have the choice. I do believe a discussion with your provider, in case they suggest a check for a particular reason, is useful and important to have. After all, you can’t base your own unique situation on the experiences of others. It also helps to have your questions/concerns answered and to make your decision a truly informed one.
The Hobbs (Purple) Line As An Alternative
I wanted to include this because I had never heard of this until I was pregnant with my son. Everyone on Twitter was talking about the “purple line” and I was like – what is that?!
So, the “purple line” is a real thing – but whether or not is a reliable indicator of labor progress or dilation is still debated. It occurs – using non-medical terms – in your butt crack and rises up and out towards the bottom of your spine (I link to Lamaze simply for the image). It seems to appear in some women when they enter the second stage of labor (also when exactly varies).
According to a study from 2010 on the purple line, it may be a useful or reliable way to measure labor progress however the authors suggest a need for more research (including studies with a more diverse population as their sample included only Caucasian women, yikes!). The study included 144 (Caucasian) women and the line did become visible for 109 of them during labor (but not always right away). There did seem to be a positive correlation of medium strength between dilation, fetal station and the purple lines length.
Verdict: it has potential, but needs more research especially with more diverse and larger populations. Why the line does not appear for everyone also needs to be better understood.
My Cervical Exam Experience
I did have 1 cervical check in each pregnancy because I also received a membrane sweep at these times. With my first I was 39+6 and with my second I was 40+1 respectively. I found cervical checks during pregnancy to be uncomfortable because of all the pressure in the pelvis – but I wanted them at this time for the sweeps, in hopes of helping labor start. It was very successful with my second pregnancy, where my son was born less than 24 hours after my sweep. I already mentioned that I did fall into the PROM category with my first – whether or not this was related to my sweep is of course, not known since I am not being studied in a controlled environment 🙂
During labor, I did have a few cervical checks. With my first, I was induced so I had to be checked for this purpose. I then did receive some checks as labor progressed – 1 prior to my epidural and I believe 1 afterwards to see my progress. I don’t remember them being particularly uncomfortable or memorable (which is why I can’t recall how many I had – because I was in labor!!), but I do think the ones prior to the epidural were, just my memory has faded because of everything else that was going on.
With my second, I did have a few checks as well during labor. One was when my midwife arrived at my house, where I had an additional sweep to increase my contractions. I had a few more to monitor progress since I was at home with less monitoring than can be offered in hospital. I did find cervical checks more uncomfortable this time – I’m not sure why. I also had a cervical lip during labor and that was unpleasant. I did find that they were all needed to monitor baby & I since we were at home.
Overall: uncomfortable for sure, for some they could even be painful (because we all experience pain differently and have different thresholds for this). I did feel that I was provided with all the information and that mine were necessary when they were done – however I am interested to see the future of non-invasive alternatives (as I would certainly prefer that!).
Cervical Exams & Risk of Maternal Fever (open access study)
Purple Line for Labour Progress (open access study)