09 Feb Considering Induction, Know Your Bishop Score
If you are considering an elective induction or facing a medical induction with some wiggle room for negotiating a few more days before the induction is determined, it may be helpful to know your Bishop Score. Basically, the Bishop Score is a calculation of 5 components used to evaluate the cervix for readiness for induction. The Bishop score is rated 0-13. This can be helpful to determine the likelihood of a successful vaginal delivery from labor induction. A score less then 6 means the cervix is not ready for induction.
The five components looked at are:
Cervical dilation – This is the measurement of the opening of the cervix. It is measured in centimeters from 0-10.
Cervical effacement – This is the measurement of the thinness and shortening of the cervix as it stretches open. It is measured in percentage from 0-100%.
Cervical consistency – This refers to the perceived feeling of the cervix. An unfavorable cervix will feel hard, like the tip of your nose. A more favorable, soft cervix will feel your bottom lip or inside of your cheek.
Cervical position – Before the onset of labor, the cervix is usually high and facing back in an posterior position behind the baby’s head. As the body is getting ready for labor the cervix will drop lower and move more into a forward-facing anterior position.
Fetal station – This is the measurement of the baby’s position in relationship to the ischial spines of the pelvis. The ischial spines are marked “0”, above the spine is measured in “+” and below in “-“.
BISHOP SCORE CHART
If you receive a low Bishop score, it is also important to consider that it may because the baby is mispositioned. When a baby is mispositioned, either in an occiput posterior position or the head is asynclitic, the baby’s head is not putting efficient, effective pressure on the cervix which can account for the low Bishop score. When the baby is in an optimal fetal position, the pressure of the baby’s head against the cervix leads to effacement and dilation. So it may not just a coincidence that the score is low. Rest assured, there are ways to help determine a baby’s position and correct it if there is suspicion that baby is malpositioned. (To better understand fetal position and how to help the baby into an optimal fetal position check out “Explanation of Fetal Position”).
Why To Avoid Induction If Not Medically Necessary
When labor is induced before the body is ready, chances increase for further medical intervention. According to a study out of Stockholm, Sweden, among women who were induced, the proportions delivered by emergency cesarean section were 42% for nulliparous (first time mothers) and 14% for multiparous (mother of more then one birth). Compared to spontaneous onset, this corresponded to a more than threefold increase in risk for nulliparous women and an almost twofold increase in risk for multiparous women. (1)
In some situations where induction is being discussed, such as the baby being past the due date, a suspected large baby or low amniotic fluid, you may be able to put off the induction for a day or so if mom and baby are OK. Unfortunately, many hospitals and doctors need to schedule an induction (and rarely will this happen on a holiday or weekend!) so you may need to be a bit aggressive should you wish to avoid induction if your Bishop score is low.
For more information on labor induction, check out Understanding Labor Induction.
Hope this information is helpful for those contemplating labor induction. Happy birthing!
(1) Acta Obstet Gynecol Scand. 2011 Oct;90(10):1094-9. doi: 10.1111/j.1600-0412.2011.01213.x. Epub 2011 Jul 21. Induction of labor and the risk for emergency cesarean section in nulliparous and multiparous women. Thorsell M, et al. PMID: 21679162