In the last article of this series on natural childbirth, we examined the little-known side effects and risks of epidurals. In this article, we turn our attention to synthetic oxytocin.
There is absolutely no doubt that induction with synthetic oxytocin (Pitocin) can be a lifesaving intervention, and is necessary in some circumstances to protect the health and well-being of both mother and baby.
The question I’d like to explore in this article is not whether induction with Pitocin is sometimes necessary – which I believe it is – but whether the frequency of its use today in hospital birth is justified. As is the case with all medical interventions, it’s important to critically examine the balance between benefit and risk – especially when we’re talking about the use of powerful drugs with otherwise healthy pregnant mothers and their babies.
There are two primary reasons that obstetricians use oxytocin: 1) to induce birth in pregnant women who are “post-term”, i.e. at 41 weeks gestation (known as “induction”), and 2) to speed up labor (known as “augmentation”). We’ll look at each of them in turn.
Is routine induction necessary at 41 weeks?
Conventionally pregnancy has been considered “post-term” at 42 weeks of gestation. At that point, if the cervix is not dilated, the current standard of practice in most industrialized countries is to induce labor.
This practice is based largely on clinical guidelines which suggested that women who reach 41 weeks undelivered are at higher risk of complications such as stillbirth.
But does the evidence really support this claim?
A meta-analysis in 2002 concluded that “routine induction of labor after 41 weeks reduces perinatal death”. According to the data, 7 deaths occurred in women allowed to go beyond 41 weeks compared to one death in women that were induced at 41 weeks.
However, of the 7 perinatal deaths that occurred, only 2 occurred from a cause possibly related to pregnancy duration. The other deaths were caused by factors unrelated to the duration of pregnancy, such as pneumonia in the newborn and diabetes in the mother. When these deaths are excluded, the difference in perinatal mortality between the group that was induced and the group that was not was not statistically (or clinically) significant.
It is difficult to argue, then, that routine induction at 41 weeks will reduce the number of stillbirths. However, it is arguable that such a practice could actually increase perinatal mortality and morbidity.
Studies in Canada suggest that the likelihood of cesarean section may be twice as high when labor is induced as compared with spontaneous labor. (We’ll discuss the risks of cesarean section in the next article.)
Furthermore, the justification that routine induction should be performed at 41 weeks to prevent possible deaths is unsound. Although the stillbirth rate at 37, 38 & 39 weeks is lower than at 41 weeks, the absolute number of fetuses who die is greater. Since more babies die at those gestations than at 41 weeks, by this reasoning we should be inducing at these earlier dates. Of course this doesn’t make sense.
As the authors of the 2002 article “Routine induction of labor at 41 weeks gestation: nonsensus consensus” conclude:
The ‘evidence’ on
which current practice and popularity of routine or as we
prefer to think of it, ritual induction at 41 weeks, is based is
seriously flawed and an abuse of biological norms. Such
interference has the potential to do more harm than good,
and its resource implications are staggering. It is time for
this nonsensus consensus to be withdrawn.
Is speeding up labor with synthetic oxytocin justified?
Official U.S. figures state a 22.3% induction rate in 2005, which is more than double the rate in 1990. In Australia rates were 25.6% in 2005, and close to 20% in England (2005) and Canada (2002). 1
The problem with augmentation is that it produces an abnormal labor. Synthetic oxytocin can interfere with the delicate orchestration of the mother’s natural hormones during birth, and according to some research, with the baby’s brain and hormones as well.
It’s crucial to understand that the effect of synthetic oxytocin is not the same as that of natural oxytocin produced by a laboring woman.
The uterine contractions produced by synthetic oxytocin (Pitocin) are different than the contractions which are stimulated by natural oxytocin – probably because Pitocin is administered continuously via IV whereas natural oxytocin is released in pulses.
Pitocin-induced contractions will be longer, more forceful and much closer together than a woman’s natural contractions. This can cause significant stress to the baby, because there’s not enough time to recover from the reduced blood flow that happens when the placenta is compressed with each contraction. The net effect of this is to deprive the baby of necessary supplies of blood and oxygen, which can in turn lead to abnormal fetal heart rate patterns and fetal distress.
In fact, birth activist Doris Haire describes the effects of synthetic oxytocin on the baby as follows:
The situation is analogous to holding an infant under the surface of the water, allowing the infant to come to the surface to gasp for air, but not to breathe.
The U.S. Pitocin package insert is painfully clear about the risks of the drug, warning that it can cause:
- fetal heart abnormalities (slow heart beat, PVCs and arrhythmias)
- low APGAR scores
- neonatal jaundice
- neonatal retinal hemorrhage
- permanent central nervous system or brain damage
- fetal death
A Swedish study showed a nearly 3 times greater risk of asphyxia (oxygen deprivation) for babies born after augmentation with Pitocin. And a study in Nepal showed that induced babies were 5 times more likely to have signs of brain damage at birth.
Pitocin can also cause complications for birthing women. Evidence suggests that women who receive Pitocin have increased risk of postpartum hemorrhage, which is likely due to the prolonged exposure to non-pulsed oxytocin. This makes the oxytocin receptors in her uterus insensitive to oxytocin (“oxytocin resistance”) and her own postpartum oxytocin release ineffective in preventing hemorrhage after birth.
In addition, Pitocin may have effects on the natural hormonal cascade which is so important to an undisturbed birth. In one study, women who received Pitocin to speed up labor did not experience an increase in beta-endorphin levels. I described the importance of beta-endorphin to the birth process in a previous article.
Hormonal disruption may also explain the reduced rate of breastfeeding following labor that was induced with Pitocin.
Again, I want to reiterate that induction with Pitocin can be a useful and even life-saving procedure, and should absolutely be used when necessary. But the evidence suggests that it is not without side effects and risks, and it should not be used in routine or otherwise uncomplicated birth.
Articles in this series:
- Natural childbirth I: is homebirth more dangerous than hospital birth?
- Natural childbirth IIa: is ultrasound necessary and effective during pregnancy?
- Natural childbirth IIb: ultrasound not as safe as commonly thought
- Natural childbirth III: why undisturbed birth?
- Natural childbirth IV: the hormones of birth
- Natural childbirth V: epidural side effects and risks
- Natural childbirth VI: Pitocin side effects and risks
- Natural childbirth VII: Cesarean risks and complications
- Buckley S. Gentle birth, gentle mothering: a doctor’s guide to natural childbirth and early parenting choices. Celestial Arts 2009. pp.110 ↩