Disturbing “New” Trends in Tear Prevention Threaten Midwives’ Autonomy
by Tine Greve

[Editor's note: This article first appeared in Midwifery Today Issue 92, Winter 2009/2010.]

During the last 20–30 years, birth statistics in the Scandinavian countries have shown an increase in the frequency of third- and fourth-degree perineal tears from approximately 1% to a disturbing 3–4%. In 1998, a study was published in the Scandinavian Journal of Obstetrics and Gynecology showing that support of the perineum during crowning of the head decreased the frequency of third- and fourth-degree perineal tears.(1) The significant difference in the frequency of tears in the two hospitals in the study was, according to the authors, only due to the use of perineal support with the modified Ritgens manoeuvre. Their conclusion stated that all women had to give birth in a semi-declined, back-lying position, in order for the midwife to have “good ocular surveillance of [the] perineum” and to perform the modified Ritgens manoeuvre on every birthing woman. Now, this has become the new routine in many Scandinavian hospitals. The main author of the study, Dr. Pirhonen, has toured Norway, introducing the modified Ritgens manoeuvre as the only way to reduce the number of tears.

Going through different studies on third- and fourth-degree tears, I find a great variety of risk factors: high birth weight, primiparas, maternal age, long second stage, use of vacuum/forceps, episiotomy, use of oxytocin, epidural, perineal oedema, etc.(2) Evident risk factors, which come up in many studies, are birth weight, primiparas and long second stage. Factors like episiotomy, use of oxytocin and epidural seem to be risk factors in some studies and in other studies seem to have a protective effect. But I haven’t found any good scientific studies that have looked at the birthing woman’s position during crowning, vocal support, or a natural, physiological birthing process.

Twenty to thirty years ago, it was good hospital routine to perform episiotomies on most primiparas (and multiparas, if you had the time). The birthing woman would be lying on her back with her legs in stirrups, and the perineum was supported using different techniques, even though there was no scientific evidence for this practice. During the 1980s, midwives became more aware of the physiology of childbirth and some studies showed an increased risk of third- and fourth-degree tears if episiotomy was performed routinely and not just on indication.(3) So, during a short time span, practice changed from routine episiotomies and full perineal support to no episiotomies and a hands-off approach, and “alternative” (read physiological) birthing positions were introduced. I’m certain, even though I don’t have many scientific, well-performed studies to prove it, that women giving birth have benefitted from the change in the regime by having better birth experiences, less perineal pain and a better sex life postpartum.(4)

Even though this new approach theoretically should decrease the frequency of third- and fourth-degree perineal tears, there has been an increased frequency during the last 20 years. And this brings us back to Dr. Pirhonen. In the study, he implies that the rise is the fault of midwives, because they stopped performing perineal support to all birthing women. Could it actually be that we were wrong? That the lack of perineal support is the sole reason for this rise in tear frequency? I don’t think so. During the same period of time, there has also been an increased use of inductions, augmentation and epidurals. With an eye on the physiology of birth, I would like to take a look at possible biases in the results of the Pirhonen study.

When talking to midwives, who primarily work with physiological childbirth, I get the impression that the rate of third- and fourth-degree tears in their birthing women is less than 1% (which is also my own experience, from almost 10 years of working in an alternative birth care unit). In addition, when they do occur, it does not necessarily surprise the midwife. I often hear descriptions like, “but you know, the baby had his hand next to his head,” “it was an occiput posterior,” “the baby weighed almost five kilos,” or “she just pushed right through.” Oftentimes, third- and fourth-degree tears occur even though the midwife did provide good perineal support. Many midwives describe the perineal damage coming not from the head of the baby, but from a protruding elbow or shoulder. Midwives do not say this to defend themselves or their skills, but merely to state that this happens when there are irregularities. So, in normal, physiological birth, it seems that third- and fourth-degree tears are more likely to happen when there are any forms of malposition or mechanical mismatch.

I’ve also talked to midwives working in hospital settings, where many women use epidurals and augmentation. When this “new” Pirhonen regime was introduced in Norway, midwives began to pay more attention to their practice on tear prevention. They became aware of the difference in the way women with and without epidurals and augmentation pushed. A woman in physiological birth is much more likely to follow her body’s signals. Those who have observed physiological birth know that when the head is crowning, the woman often stops pushing, even though she is having a contraction. She will often start panting or grunting and at the same time, if she is free to move, retract the leg where the first shoulder is facing. This creates a twist in her hip, allowing the first shoulder to descend into the pelvic outlet. She responds to her body’s signals by moving in ways that delay the crowning, which makes the perineum stretch and less likely to tear. A woman giving birth with augmentation and epidural does not have the same experience during the second stage. When she is numb she might not get the pushing urge, and she might need vocal guidance and support in order to know when to push and when not to push. If she’s pushing by will alone and not with the guidance of an urge, she does not have the same control of the strength of her pushes. This may result in pushing too early (before the head is fully rotated and/or on the pelvic floor), leading to the risk of prolonged second stage. Also, she is more likely to push too hard, and her contractions might be stronger due to the augmentation. If she pushes very hard on strong contractions, the crowning may occur so fast that the perineum is not allowed to stretch slowly, increasing the risk of rupture. It is obvious that perineal support in these situations can provide good tear prevention.

This might be important to have in mind if you start looking at the risk factors for tears described earlier in this paper: primiparas (more likely to have inductions, prolonged labour, epidurals and augmentation), high birth weight (more likely to have inductions, prolonged labour, epidurals and augmentation), and long second stage (more likely to occur if there is a malposition or mechanical mismatch). So could it be that it is not the support of the perineum itself, but to whom we provide perineal support, that could be the clue to success? Understanding physiological birth, we also have the knowledge of how interferences in the birthing process can influence the outcome.(5)

So, imagine a woman in labour, in the beginning of the second stage, having been able to follow her body through the birthing process, not influenced by painkillers or Pitocin. She’s standing on the floor, leaning on her partner, just starting to push. You, the midwife, can see the black hair of the baby in the vulva. Now you ask her to lie down on her back, feet in the stirrups (so you can get a “good ocular surveillance of [her] perineum”), and you support her perineum by using the modified Ritgens manoeuvre. Yes, she might not suffer any severe perineal tears; but what about her birth experience, her breastfeeding start, her bonding with the baby? And what was the initial risk of her having severe perineal trauma?

This is supposed to be the regime if Dr. Pirhonen’s rules are to be followed. Seen in the light of what happened when the change in regimes went from episiotomy and support to no episiotomies and hands-off, I do understand the logic in providing perineal support to all birthing women. Midwives who were not good enough at evaluating which women still needed perineal support and, therefore, did not provide support to those who actually needed it might, to some extent, have contributed to this increased rate of third- and fourth-degree tears.

So how do we solve this? By following Dr. Pirhonen’s recommendations and providing perineal support to all women? Or, should it be possible for the midwives to do individual evaluations of each birth and provide support to those at risk of severe perineal damage?

Looking at the fact that midwives who work with physiological childbirth have a very low incidence of third- and fourth-degree tears, I do think it should be possible for midwives to do this evaluation. It requires that the midwives be taught physiological birth in midwifery school, that they are aware of risk factors, that they learn the skills of good perineal support when it is needed and that they are allowed to work autonomously. In addition to this, midwives must also be aware of means to reduce the risk factors for perineal damage. Is it being a primipara that enhances risk or is it the increased incidence of induction, augmentation, epidural and prolonged labour in primiparas that creates a larger risk for perineal damage?

My conclusion is this: Help those with initial risk factors, like primiparas and those with high birth weight babies, reduce their risk by avoiding the use of induction, augmentation and epidural. Give women the possibility to go through a natural, physiological birthing process without disturbances. When risk factors are manifest, do provide good perineal support.

Hands off when not needed! Hands on when needed!

Author’s Note: In this article I have chosen not to address the effects of preventive measures, e.g., maternal diet, ante- and intra-partum massage, etc. You can read about those in various other Midwifery Today articles. You can learn more about the subject of this article at the Midwifery Today conference in Philadelphia, Pennsylvania, April 14–18, 2010.

Tine Greve, IBCLC, has been a midwife in Denmark and Norway. She worked at the Alternative Birth Care Centre in Aker Sykehus, Oslo, Norway, from 1997 to 2005. She now works at the National Resource Centre for Breastfeeding at Rikshospitalet, Oslo, Norway. She has been a speaker at many Midwifery Today conferences. Tine has three children: Astrid, Sigurd and Solveig.

Other Resources:

References:

  1. Pirhonen, J.P., et al. 1998. Frequency of anal sphincter rupture at delivery in Sweden and Finland—result of difference in manual help to the baby’s head. Acta Obstet Gynecol Scand 77(10): 974–77.
  2. Samuelsson, E., et al. 2000. Anal sphincter tears: prospective study of obstetric risk factors. BJOG 107 (7): 926–31; Clemons, J.L., et al. 2005. Decreased anal sphincter lacerations associated with restrictive episiotomy use. Am J Obstet Gynecol 192(5): 1620–25; Eskandar, O., and D. Shet. 2009. Risk factors for 3rd and 4th degree perineal tear. J Obstet Gynaecol 29(2): 119–22; Samarasekera, D.N., et al. 2009. Risk factors for anal sphincter disruption during child birth. Langenbecks Arch Surg 394(3): 535–38; Valbø, A., et al. 2008. Anal sphincter tears at spontaneous delivery: A comparison of five hospitals in Norway. Acta Obstet Gynecol Scand 87(11): 1176–80.
  3. Wilcox, L.S., et al. 1989. Episiotomy and its role in the incidence of perineal lacerations in a maternity center and a tertiary hospital obstetric service. Am J Obstet Gynecol 160(5 Pt 1): 1047–52; Borgatta, L., S.L. Piening, and W.R. Cohen. 1989. Association of episiotomy and delivery position with deep perineal laceration during spontaneous delivery in nulliparous women. Am J Obstet Gynecol 160(2): 294–97; Thorp, J.M., Jr., and W.A. Bowes, Jr. 1989. Episiotomy: Can its routine use be defended? Am J Obstet Gynecol 160(5 Pt 1): 1027–30.
  4. Sleep, J., et al. 1984. West Berkshire perineal management trial. Br Med J (Clin Res Ed) 289(6445): 587–90.
  5. Odent, Michel. 1999. The Scientification of Love. London: Free Association Books Ltd.

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