Research Regarding the Benefits of Pitocin Augmentation
Pitocin augmentation may be suggested during spontaneous labor (labor that began without induction methods) if your clinician believes that your cervix is dilating (opening) at a slower than normal rate. Pitocin is a synthetic version of the hormone Oxytocin, which has several functions, including stimulating uterine contractions. Pitocin is a medication that is administered through an intravenous infusion at a dose that is guided by the frequency of uterine contractions or Montevideo units (in cases where an IUPC, Intrauterine Pressure Catheter, is used). Augmentation is an intervention that is intended to speedup the rate of cervical dilation in a spontaneous labor, a labor that has begun on its own unlike an induced labor. What constitutes slow cervical dilation and whether slow labor progress increases the probability of bad outcomes will be discussed in the next month’s essay. Instead, this entry will focus on research regarding the proposed benefits of Pitocin augmentation.
As a nurse in labor and delivery, I heard numerous clinicians say that Pitocin augmentation is going to increase the likelihood of a birth canal birth and reduce the complications of prolonged labor. These claims seem plausible on account of the fact that Pitocin infusion, quite reliably, increases the frequency of contractions. However, whether the more frequent contractions have a positive effect on the type of delivery should not be assumed. Hospital personnel typically acknowledge three elements affecting labor progress; namely, the size of the baby (Passenger), size the pelvis (Passage), and strength/frequency of contractions (Powers), typically referred to as the 3 P’s. Initiating Pitocin in spontaneous labor where cervical dilation is deemed slower than normal, assumes that just pushing the baby through the birth canal with more force at an increased frequency, improves the chance of a birth canal birth. Additionally, it is assumed that if the labor is hastened by means of Pitocin, the adverse outcomes associated with prolonged labors will be ameliorated. However, current research does not support these assumptions.
In 2013, the Cochrane researchers conducted a systematic review (Bugg, 2013) of studies that evaluated whether Pitocin augmentation reduces the likelihood of a cesarean birth and if it has an effect on specified morbidity parameters. This review identified eight studies for inclusion, which examined individuals with term low-risk pregnancies, whose labor began spontaneously, and who experienced slow cervical dilation. The overwhelming majority of participants were nulliparous, or first-time birthers.
Three studies evaluated Pitocin augmentation against no treatment. Unfortunately, these studies had a rather small number of individuals, making the results less reliable. However, it is still of value to note that no statistically significant difference was found in terms of cesarean births, use of vacuum or forceps for delivery, newborns with a poor 5-minute Apgar score (a measure of the baby’s vitality), or proportion of births via the birth canal between the group that received Pitocin augmentation for slow labor progress and the group with slow labor progress that relied on their body’s innate ability to birth.
Five trials compared initiating Pitocin augmentation when the cervix was fist noted to be dilating slower than normal versus delaying Pitocin initiation by somewhere between 3 and 8 hours after the diagnosis of slow labor progress. Dilation rate was deemed slow if it was 0.5cm per hour or less. There was a large enough sample to make the results of this analysis reliable. In the studies that reported fetal heartrate patterns, those babies who were exposed to Pitocin earlier, had more frequent heartrate changes indicative of substantial interruptions in oxygen. However, the study that contributed the most data to this analysis, utilized a Pitocin protocol that aimed for excessive contraction frequency, which could have been the reason for this observation. There was no meaningful difference in the rate of cesarean deliveries between those who received Pitocin immediately and those whose Pitocin augmentation was delayed by several hours. There were more people among the delayed Pitocin group who were still pregnant after 12 hours from the time that slower labor was first detected, but that difference was not statistically significant, meaning that it could have resulted from coincidence and not represent an actual difference. Additionally, no difference was observed between the two groups in terms of poor Apgar scores or newborn delivery assisted by vacuum or forceps. The studies that reported admissions to the neonatal intensive care unit (NICU), have not noted a statistically significant difference. When postpartum hemorrhage (heavy vaginal bleeding after delivery) was evaluated, there was no statistically significant difference between the two groups.
Other researchers (Rossen, 2015) have found that delaying Pitocin augmentation by 4 hours after the diagnosis of slow labor progress decreased the frequency of Pitocin augmentation, birth by cesarean, and instances of umbilical artery pH <7.1 (pH lower than 7.1 indicates that the baby was seriously deprived of oxygen during labor). Conversely, after the delayed Pitocin protocol was introduced there was an increase in labor duration as well instances of severe blood loss after delivery. However, the results of this trail should be treated with caution, because randomization of participants did not take place in this study, the two groups being compared differed in important ways. For example, the group that had their Pitocin administration delayed, had proportionately more people undergoing an induction of labor; hence, they were not receiving Pitocin for augmentation. The reason why that is important is because people undergoing inductions have more frequent instances of severe blood loss (Belghiti, 2011).
In summation, there is currently no evidence that Pitocin augmentation has an effect on the rate of cesarean births. The Cochrane review (Bugg, 2013) had a large enough sample to detect a 30% or greater increase or decrease in cesarean section rates as a result of Pitocin augmentation. Initiation of Pitocin did not increase the likelihood of a birth via the birth canal or decrease the use of forceps or vacuum for delivery. It is possible that Pitocin augmentation can have an effect on cesarean section rates, although the effect would be slight. Furthermore, there is no evidence that avoiding Pitocin augmentation or delaying its administration by several hours, increases bad outcomes (low Apgar score, NICU admission, or low blood pH) for the newborn. No clear evidence exists that Pitocin augmentation reduces the risk of severe bleeding after delivery. What Pitocin augmentation has been shown to do, is reduce the length of time to delivery by an average of a little over two hours (Bugg, 2013). In light of these findings, a conversation with the obstetric provider about research supported risks and benefits is advisable.