Waterbirth Reduces Vaginal and Perineal Tears – New Report

Aquabirths Canberra birth pool iimage
Picture: Lorne Campbell / Guzelian

It’s always exciting when new research into Waterbirths comes out because they’re fairly few and far between. In this case, it’s a report from the USA1 where waterbirth is less well supported than it is in the UK and Europe. The report looks at a variety of outcomes, including how waterbirth reduces the incidence of vaginal and perineal tears, postnatal haemorrhage, Apgar scores and neonatal unit admissions.

Although this wasn’t a randomised control trial, it was a high quality retrospective study which looked at matched comparisons, so ‘like for like’ women with similar pregnancies and risk factors were properly compared. This means that the outcomes can be relied upon to be accurate.

Most outcomes were the same between the two groups (which were women who birthed in water and women who birthed on land). There were no differences between the numbers of women who experienced significant blood loss, but also there were no statistically significant differences between the numbers of babies admitted to the neonatal unit, and Apgar scores were similar between the groups.

There was one big difference though. The numbers of women who experienced first or second degree tears to their vagina or perineum were significantly reduced when the women laboured and birthed in water.

Aquabirths have previously written about the challenges of reducing vaginal and perineal tears, and our concerns about the OASI bundle. It is so important to consider the use of birth pools when looking to reduce the numbers of women who are experiencing these serious birth injuries, which can be life changing. Increasing the number of women who are accessing water to labour and birth in hospital, in midwife led units and at home is a low cost way for Trusts to support normal physiology and reduce the number of unnecessary birth injuries.

The evidence on the safety of waterbirth is overwhelming. We know that birth in water is safe for women and babies. We know how to support waterbirth for women who have a high BMI, are being induced, are having a VBAC or who are carrying Group B Strep. We know how positive and empowering waterbirths2 are for women, and we know how powerful the pain relieving3 aspect of a birth pool is.

So many obstetric units’ birth pools are underused. What can you do to increase the numbers of women using it? Can you take that on as your task for the month?

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OASi – The Right Care for Serious Tears?

The OASI Bundle refers to a specified list (the Bundle) of interventions which are being evaluated to see whether they reduce the numbers of very serious tears during birth, known as OASI, which affect the woman’s anal sphincter. The package is outlined by RCOG here. These types of tears can be hard to repair, and can lead to life changing injuries for women. While Aquabirths absolutely supports the concept of trying to reduce the chances of these types of birth injuries, there are some serious concerns about the OASI Bundle and whether it is the best way to achieve this.

OASI stands for “Obstetric Anal Sphincter Injury”. The Bundle contains four components:

  • Communication with women about their chance of OASI (more about this in a moment)
  • Using the “Finnish Grip” as the baby is born
  • Use of episiotomy as per indications in the details of the Bundle
  • Checking the mother by inserting a finger into her rectum and feeling for tears which might not be immediately obvious and which can be present even if her perineum is intact.

We were initially pleasantly surprised to see a list which specifically included the requirement to speak to women about the intervention. While sometimes a guideline will say “do X with consent”, rather than just “do X”, it is very exciting to see a specific component of a Bundle being that women should be making an informed decision to be a part of a trial. However – despite being the first part of the Bundle (after all, nothing can be done without consent) the fact that this component is listed last in RCOG’s detailed guidelines speaks volumes about the consideration of its importance. Even more worryingly, in practice, midwives are reporting that women are arriving at hospital in labour without having been given information about the Bundle by their community midwife and therefore ensuring that ensuring that informed consent is given is much harder. This should itself invalidate the data that is being collected by the trial, according to its own rules, and performing any intervention on women without informed consent is, in law, common assault.

The Finnish Grip is the main intervention in OASI. It involves gripping the perineum with the intention of redirecting pressure towards other vaginal and labial tissues. This video shows it in practice (keep the sound off – the artificial sound effects are somewhat irritating, especially the “push-push-push”!) You will note from the video that the “woman” is on her back, pushing against gravity with her baby’s head therefore pressing down hard against the perineum. The Finnish Grip is designed to push the baby’s head up and away from the perineum – yet encouraging women to be upright or forward facing has the same effect! With an upright, forward facing or even side lying position the baby’s head is lifted by gravity towards the woman’s front, rather than being dropped by gravity heavily onto the perineum. The Finnish Grip also displaces the pressure of the baby’s head towards the clitoral area, and this causes increased numbers of tears in this area, often with serious loss of sexual feeling for women. These tears are considered to be less severe than anal sphincter tears (although partly this is because reduction of female sexual function is often considered to be of less importance than it is to the individual woman) – and again, we would not want for a moment to understate the catastrophic consequences of these – but what if there is another way?

What we know about perineal trauma is that women who birth on their backs, perhaps in lithotomy, are more likely to experience serious tears than women who birth in upright positions. Women who birth in water experience fewer serious tears, and the OASI Bundle cannot be used in water. The evidence around waterbirth reducing the incidences of severe tears has been well known for years, and we welcome hearing HCPs suggesting waterbirth to women who are worried about their personal risk of a severe tear, or who are at higher risk of it.

We also know that some obstetric interventions can increase the risk of OASI. For instance, inductions and epidurals lead to a higher chance of birthing lying down or in lithotomy, which as I’ve already discussed leads to gravity pulling the baby’s head more firmly down onto the perineum. However, the very low rates of severe tears in women who birth without pharmaceutical pain relief (allowing them to follow their instincts more clearly and leaving them with the sensations from their bodies to respond to), especially in low-medicalised environments such as home births or midwife led unit births, lead many to feel that there are other ways to reduce OASI without pinching a woman’s genitals as she is trying to push a baby through them.

Many midwives have noted how women will naturally close their legs together to slow the birth of the head – and yet how many women are encouraged to open their legs to “make space for the baby”? In artificial birth positions such as lithotomy, this is simply not possible, which may explain the higher numbers of tears which the Bundle is trying to reduce.

Margaret Jowitt has introduced an interesting theory that in upright or forward leaning birth, the baby’s head presses against the clitoris (again, as the pressure is spread towards the opposite side to the perineum), and in a spontaneous birth where the woman’s and baby’s bodies are working together the baby’s head could be “cushioned” by the the internal parts of the clitoris, (the bulbs and the crura), triggering it to enlarge and gently support the baby as the head passes through and out of the vagina. Midwife Joy Horner discusses the need for the vaginal and perineal muscles to soften and relax, much like is needed for comfortable love making, and a supportive, loving birth environment with a known and trusted care giver (continuity of carer!) who would not interfere with that oxytocin creation could explain why independent midwives have such low rates of OASI.

It is deeply worrying that we are seeing signs, during this OASI trial, that women are not being given information antenatally to ensure that they can give informed consent during their birth despite the fact that this is a key part of the Bundle. The Finnish Grip appears to be trying to rectify a problem which may well be caused in the main by over-medicalising birth and not supporting women to follow their instincts, and the damage that the Finnish Grip can cause with the associated increase in labial and clitoral tears may cause more women problems than would have suffered with anal sphincter tears. Instead of rolling out yet more intervention, perhaps it’s time to take a step back and look at supporting more women to birth in water, or to have more continuity of carer to ensure that during one of the most intimate periods of their lives, women and their carers can feel the deep and loving bond that even the very best, most caring midwives cannot be expected to develop when they meet for the first time in a hospital setting.