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Overview

In the last month of your pregnancy, you will be seeing your doctor or midwife weekly. Vaginal exams take place during your pregnancy in the last few weeks leading up to your birth and during your labor. The question is, are they really necessary and will you benefit from the results? Vaginal exams have become a routine, but questions about what the results show, the risks involved, and the psychological effects of the results have some expecting moms questioning whether they want to opt into these procedures. Learn what is involved during a vaginal exam, how the results are interpreted, and what the results mean for you and your baby. This episode presents all of the considerations, research and evidence to help you make an informed decision about vaginal exams.

Article and Resources

As you get closer to your due date the frequency of your appointments with your doctor or midwife also increases. In the last month of your pregnancy, you can expect to see your care provider every week. One intervention that may be offered at one of these appointments is a vaginal exam. This is also an exam that can take place during labor.

How a Vaginal Exam Works

A vaginal exam is exactly what it sounds like. Your doctor or midwife will be examining your vagina to measure your cervix. Before this appointment starts you will want to empty your bladder. It probably isn’t a bad idea to start every appointment this way, especially as your uterus grows and puts more pressure on your bladder. You will be asked to remove your clothing from the waist down and lie on an exam table. Your care provider will insert a gloved finger or two fingers into your cervix to examine it. They do this to determine whether your cervix has begun to dilate or efface. This exam can also help them determine the position of your cervix and the station and position of your baby.

This is really an oversimplified explanation of everything this exam is measuring. It is also important to remember that in labor there is a lot going on in your body that you may not be aware of. There are a lot of pieces to this puzzle and they are all moving to come together and create the conditions your baby needs to be born. To really understand this procedure let’s dig more into these measurements.

Cervical Dilation

Cervical dilation is measured in centimeters. The first stage of labor is from the onset of labor until you are 10 centimeters. To give you a tangible idea of dilation measurements consider the following:

  • Early labor
    • 1 cm = cheerio
    • 2 cm = grape
    • 3 cm = quarter
  • Active labor
    • 4 cm = oreo
    • 5 cm = mandarin orange
    • 6 cm = soda can
    • 7 cm = tomato
  • Transition
    • 8 cm = apple
    • 9 cm = donut
    • 10 cm = bagel

How Cervical Dilation is Measured

A doctor or midwife measures cervical dilation by inserting two fingers in your vagina and placing them on either side of the vaginal opening and estimating the distance between the two fingers. This is not an exact science. One study set out to determine how accurate a vaginal exam is during labor. To asses this a researcher performed a vaginal exam immediately following a clinician. In 49% of the exams, both agreed on the measurement of dilation. In 51% of cases, the two did not agree, and in 11% of these cases, their findings differed by 2 cm or more. These are big differences and this study demonstrates that these measurements are not exact.

Cervical Effacement

Cervical effacement is measured as a percentage from 0-100%. At 0% your cervix feels like the tip of your nose, it is closed and pretty hard, as the cartilage in your nose. At 100% it will feel soft like your lips and is paper-thin.

Mucus Plug/Bloody Show

During pregnancy, your cervix stays rigid and closed to protect your baby and keep them inside your belly. As your cervix dilates and effaces during labor you may lose your mucus plug. This is sometimes referred to as your bloody show because the mucus may be red and have tinges of blood in it. This is a sign of labor that you may or may not experience. Plus, this could happen several days before you go into labor or at the onset of labor.

The Position of the Cervix

During a vaginal exam, your doctor or midwife will also examine the position of your cervix. During your pregnancy, your cervix is posterior and points towards your tailbone. As you are nearing labor, or in labor, your cervix will move forward to an anterior position so your baby has an easier path to get out.

Station of Your Baby

Within a few weeks or a few hours before your birth your baby will settle into your pelvis. This movement is referred to as lightening or your baby dropping. This position of your baby’s head in relation to your pelvis is measured in stations. The station is measured on a scale of -5 to +5. At a station of -5, your baby’s head is not yet into your pelvis. A zero station means your baby’s head is engaged in your pelvis. A +5 station is when your baby is crowning.

One study found that these measurements may not be reliable. The study used a birth simulator that had accurate measurements of the baby’s head and 57 doctors gave measurements of the fetal station and the majority of them did not get the measurement correct.

Position of Your Baby

Your doctor or midwife will also be looking to determine the position of your baby. They may be able to tell this by palpitating your belly. They can also determine which way your baby is facing by feeling their skull during a vaginal exam. The bones in your baby’s skull are not fused together at birth. This is a good thing because it allows their skull to fit more easily through your pelvis. This is the reason why some babies are born with a slight cone-shaped head. (Don’t worry, this does not last!) There are soft spots that allow the bones of the skull to overlap. By feeling the position of the soft spots in your baby’s skull, your doctor or midwife can tell which way they are facing. For an in-depth article on your baby’s position, you can check out this article. 

Bishop Score

All of these measurements can factor into a Bishop score. This is a scale of one to ten that predicts your likelihood to go into labor. A score of one means you could be weeks away and a score of 10 is supposed to indicate that you are days away. There has been some controversy over bishop scores as a predictor of labor. While your Bishop score may not be the best predictor of when you go into labor, it may be relevant if you are considering an induction. This study shows that lower bishop scores are associated with higher rates of cesarean birth when labor is induced. Inductions tend to be more successful when your cervix has already started to dilate and efface.

Clinical Guidelines

Internationally, the consensus on vaginal exams during labor is to offer them every four hours during labor. Unfortunately, I could not locate any published guidelines from ACOG on the recommended frequency of vaginal exams. The National Institute for Health and Clinical Excellence (NICE) in the UK recommends expecting mothers are offered a vaginal examination when they enter a hospital in suspected established labor and every 4 hours as labor progresses. The World Health Organization states vaginal examination at intervals of four hours is recommended for routine assessment of the active first stage of labor in low-risk women.

The Evidence

A Cochrane review that examined two studies on routine vaginal examinations during labor. The authors of the review concluded: “It is surprising that there is such widespread use of this intervention without good evidence of effectiveness, particularly considering the sensitivity of the procedure for the women receiving it and the potential for adverse consequences in some settings.” The two studies covered in the review were done in the 1990s in high-income countries, and there is some question to their quality. One study, involving 307 women, compared routine vaginal and rectal examinations in labor. In this study, fewer women reported that vaginal examinations were very uncomfortable compared with rectal examinations. The other study in the review, involving 150 women, compared two-hourly and four-hourly vaginal examinations, and no difference in outcomes was seen.

Why Care Providers Perform Vaginal Exams

Exams and measurements to predict labor are very attractive to medical professionals. The medical community likes metrics. Things that can be measured help care providers create policies and procedures to navigate health care. So much of what is happening during your birth is internal and it can be challenging for a doctor or midwife to know exactly where you are in the labor process. Especially within a system where care providers feel like they need to manage your labor and deliver your baby.

In the past doctors expected cervical dilation to progress by one centimeter per hour. More recent research and this systematic review challenged this guideline. Research has shown that the one centimeter per hour guideline is not realistic and that cervical dilation patterns are not linear. The rate of dilation typically accelerates after 5 or 6 centimeters, during the active phase of labor. Plus, the rate at which the cervix dilates and effaces varies greatly from one expecting mother to the next.

There are many clues your care provider will pay attention to leading up to and during your labor. These clues include how you feel about your due date, your health, your baby’s health, your contractions, how well you are tolerating labor, and how well your baby is doing during labor. The main reason vaginal exams are done is to give your doctor or midwife clues to two things. The first is how your labor is progressing. The second is to determine you are at 10 cm before you start pushing.

Measuring Progress

Your doctor or midwife wants to know that labor is progressing. If you are dilated to 2 cm, and four hours later you are at 7 cm that is tangible evidence that your labor is moving forward. The problem is that everyone’s labor progresses at different rates and it is not a steady linear measurement. You could take 4 hours to go from two to three centimeters, then progress to 6 centimeters in under an hour.

Reaching 10 cm Before Pushing

It is accepted in the medical community that you should be dilated to 10 cm before you start pushing. The thinking behind this is that if you are not fully dilated pushing isn’t going to help your baby get out because they do not have enough room to make an exit. In general, with a drug-free birth, you are going to get an urge to push, which likely happens around 10 cm. If you have an epidural, you may not have as much feeling and may not have the same urges to push. The majority of births, especially in the United States are done with an epidural.

Is a Vaginal Exam Considered an Intervention?

An intervention is defined as the action or process of intervening, or an action taken to improve a situation, especially a medical disorder. I define an intervention is any action taken to alter the course of your pregnancy or birth. The results of a vaginal exam could influence your decision to induce labor, opt into a cesarean birth, or affect your attitude or expectations about when you will go into labor or how your labor is progressing.

The Value of a Vaginal Exam for Your Care Provider vs. the Value to You

You can see that a vaginal exam has a lot of perceived application to your doctor or midwife. Especially in institutions where they have procedures in place to perform routine exams leading up to your due date and during your labor. You need to think about the value and benefits that a vaginal exam has for you. Once you are clear on the benefits of a vaginal exam you can weigh those against the potential risks.

Don’t Focus Solely on the Numbers

Your cervix has a lot of work to do before your baby is born and the centimeters dilated and the percent effaced don’t give you the whole story. From your care providers standpoint, these are useful numbers but you can also take into account how you are feeling. You have the unique perspective of being the person in labor so you have the best sense of everything going on in your body.

What a Vaginal Exam Tells You

Results of a vaginal exam may be useful, but they cannot accurately predict when labor will start or how much longer you will be in labor. You could be dilated to 2 cm for weeks before you go into labor and still go past your due date. If you are in labor and progress from 2 to 3 centimeters in an hour there is no guarantee that in another hour you will be at 4 centimeters. You may still be at 3 centimeters, or you could be at 6 centimeters. Remember that your body is working very hard to get all of the pieces in place for your baby to be born and there is a lot of progress you and your care provider may not see or be able to measure.

You may want to know the status of your cervix purely out of curiosity even after you understand that this cannot accurately predict when or how long you will be in labor. If you are considering inducing labor understanding whether your cervix has begun to dilate and efface may indicate that you have a higher probability of a successful induction.

Risks of Vaginal Exams

There are some risks involved with vaginal exams. Like any exam or procedure, your doctor or midwife should be discussing this with you and only proceeding with your informed consent.

Vaginal exams can be physically uncomfortable. A study based on interviewing women postpartum found 82% of women reported pain or severe pain and 68% reported discomfort during a vaginal exam.

You may have spotting or additional discharge afterward. There is a risk of infection due to the chance of bacteria from the vagina being pushed up into the cervix. It is possible you could have a premature rupture of your membranes. There is some speculation that an exam can stimulate your cervix and contribute to early labor. I had a hard time finding evidence to support this. Typically vaginal exams are not done until a few weeks or less prior to your due date which would theoretically minimize your risk of early labor. It is normal for your baby’s heart rate to accelerate during a vaginal exam. Usually, this exam is not done in conjunction with fetal monitoring unless it takes place during labor.

Psychological Impact

We often don’t talk about the psychological impact of an intervention or procedure, and this can be a big deal. Depending on how the results of the exam are communicated you could be excited that labor is starting soon or disappointed that it isn’t. If you are under the impression labor will start soon and it doesn’t that can be a disappointment. You may have some anxiety that your body is not going into labor as quickly as you or your care provider expect. Please make sure that you understand the results of this exam. If you have questions please bring them up with your doctor or midwife.

An Alternative to a Vaginal Exam

In the future, we may have more access to an alternate method of measuring your cervix by using ultrasound, rather than a doctor or midwife manually checking your cervix. The big plus of this method is that it is less invasive than someone inserting fingers in your vagina. This could also limit some of the risks associated with traditional vaginal exams.

Measurements with a Transperineal Ultrasound

One study looked at a transperineal ultrasound to diagnose active labor at 4 cm of dilation or more and found ultrasounds to be effective than a vaginal exam. Ultrasounds were less effective at measuring when dilation reached 8 cm or more or when the membranes were ruptured (water had broken). Another study compared a vaginal examination to a transperineal ultrasound during labor to look at outcomes on pain and anxiety. This was a randomized controlled trial of 90 women and it showed pain was lower with an ultrasound done on the perineum, rather than a traditional vaginal exam. The ultrasound did not have any clinically relevant effects on anxiety. This research found that ultrasound was more effective at measuring fetal head position and station than a traditional vaginal exam, but less accurate at assessing cervical dilation.

It will be interesting to see if this technology changes the way we do things in the future and becomes more widely available. If this is an option you would like to consider you can ask your doctor or midwife whether this is an available option.

Your Options

As with any procedure you have several options for a vaginal exam. You can refuse the exam altogether or ask that they be limited. You can also request to have a vaginal exam if you want the measurements taken. If your care provider offers a vaginal exam at 37 weeks and you want to wait until your due date you can wait. This article has given you a lot of pros and cons to consider to decide if and/or when you want a vaginal exam in the last weeks of your pregnancy or during your labor.

Talking to Your Doctor or Midwife

Please discuss any questions or concerns with your doctor or midwife. You should be confident about the informed choice you are making about this procedure. Your doctor or midwife should also be explaining the pros and cons of this procedure prior to performing it. I know that can be challenging to fully discuss a complicated procedure during a short appointment. That is why it is so important for you to ask questions if you have them. Your doctor or midwife cannot do this without your informed consent and it is ultimately up to you.

Potential Questions to Ask Yourself or Your Care Provider

You should be able to ask your care provider any question. Here are some ideas of questions you can ask to help evaluate your options for a vaginal exam.

  • Why should I get a vaginal exam?
  • How will the results affect my care?
  • If you would like to wait: Can we delay it? A week, an hour?
  • Remember the BRAIN acronym for evaluating interventions:
    • Benefits – What are the benefits?
    • Risks – What are the risks?
    • Alternatives – What are the alternatives?
    • Intuition – What does your intuition tell you?
    • Nothing – What happens if you do nothing?

Including Vaginal Exams in Your Birth Plan

This is a procedure you may want to include in your birth plan. This involves more than simply writing a sentence about your preference for vaginal exams. If you would like to include this please discuss it beforehand with your doctor or midwife and make sure you are on the same page about if and/or when vaginal exams should be used. If you are stuck with writing a birth plan you are welcome to get a copy of my birth plan I used as an example. The Your Birth Plan book is also a good resource with step-by-step instructions, templates, and sample plans for every type of birth.

 

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