The Bishop Score
Have you ever heard of a Bishop Score? This is the ‘rating’ that we give a pregnant person’s cervix in order to determine its readiness for induction. There are a few key flaws in this scoring system and I want to chat it out!
The History of The Bishop Score
The original Bishop score (Developed by Dr. Bishop, OBGYN in 1964) is based on 5 criteria: dilation, effacement, station of baby, position of cervix, consistency of cervix. You will be given a score of 0 to 3--0 being not progressed and 3 being the cervix is showing favorable progress-- for each of these criteria(Note: the highest score for position and consistency of cervix is 2). You will be given an overall Bishop Score which will indicate if you are a good candidate for induction or if you are not. The highest score is 13 and any score 9 or above is considered ‘favorable’ for induction meaning the numbers suggest your body will be receptive of induction. (Note: some providers will use 8 and this will be up to you as to what number you feel most comfortable)¹. You can see a Bishop Score card here!
However, this 2012 study used a ‘Simplified Bishop Score’ that only considered dilation, effacement, and baby’s station. It showed a similarly high predictive rate to the original bishop score. This means if you are favorable in those three out of five, you may be a great candidate for a 39-week induction (if it aligns with your birth goals).
The Problems with The Bishop Score
Interestingly enough, it is not a great tool for people who have had a baby before. Since your body has already done this a time or two, your cervix can change on a dime. Anyone’s cervix can rapidly change (which is why this is flawed to begin with), but a person who has already given birth is more likely to have faster cervical change making the Bishop score less reliable for second and third (and beyond) time mothers.²
One final problem is--and I eluded to it above--but providers are not consistent in their expectations or usage of the Bishop Score. Some use 8, some use 9 as an indicator of a ‘favorable’ cervix. Some use a 8 or 9 until they realize that the patient isn’t achieving that score then they throw in a ‘well, by the simplified bishop score you meet criteria’ which is equally confusing and infuriating. Many women leave feeling confused if they are a good candidate and infuriated with a provider that was not clear on such a big decision.
Here’s the thing: it is a flawed tool, but it is the best we have at the moment.³ It does a pretty good job of indicating your body’s receptivity to a medical induction. This is definitely a tool to be aware of and to know your personal boundaries of what you consider a good number to induce your body. Remember consent is a discussion with your provider--make sure that is being done around the topic of induction especially.
What you need to know as a consumer?
First and foremost you should understand the reasons for medically necessary indcutions. As a consumer, you have a responsibility to take control of your birth experience and this includes being an informed consumer. You need to know the evidence behind bogus reasons for inductions like ‘big babies,’ ‘advanced maternal age,’ or ‘late babies.’ You also need to understand how to navigate sticky places like Gestational Diabetes. It doesn’t always mean you have to be induced or that you’re doomed for a ginormous baby that’s going to rip you to shreds. (Note: Sometimes, GD does require an induction to keep parent and baby safe) Those are fear-based approaches and I hope dearly your provider isn’t trying to pull this with you. Here is a list of medically necessary reasons to consider being induced.
This is a good study to be aware of! It is older (2006) and shares that if you have a positive Bishop score, and use a specific method of induction (This is really nice to know exactly what protocol to follow--unlike The ARRIVE Study!) This study had 99 participants, 47 first time moms, 52 moms who had given birth before (did not decipher second, third, etc). The median time of labor time for first time moms was 15.5 hours and for those who have given birth before, median labor time was 12.5 hours. 20/47 first time moms got an epidural and 11/52 moms who had birthed before got one with 83 vaginal births. They had 16 total c-sections with 8 due to fetal distress (funky fetal heart tones). There were also 8 first time parents and 8 parents who had birthed before. 45% of participants were in labor after only one Misoprostol and 45% were in labor after two doses. This left 9 participants whom seven need 3 doses and two needed 4 doses. 11 newborns required a NICU stay.⁴
If you are facing pressure from your provider about The ARRIVE Study (a study that shares a 39-week induction may lower your risk of a c-section). You can read more about that study and how to understand whether it applies to you and your birth goals, here.
If you have a failed induction, you are allowed to leave the hospital. We will be covering this SOON!
If being induced is not aligned with your birth goals and you have a preference to wait or to wait for labor to initiate unassisted, then that is absolutely your right. You can read all about due dates here and how your due date is a guess! Science is on your side if you decide waiting is best for you!
If you want to learn more about your birth choices or how to advocate for your birth goals, join The Birth Lounge!