Jan Willem de Leeuw

and 6 more

Delivering in or out of water, the OASI rates in the POOL cohort study are disturbingly highDear Dr Papageorghiou,We have read with interest the POOL study report by Sanders et al. published in your journal.1 We acknowledge that the results of this study are based on a large obstetric cohort of low-risk women.The mere conclusion of the authors is that birth in water is not associated with increased risks for mothers and babies. However, in doing so, they seem to have overlooked an important issue related to the event rate in their comparator group. Indeed, the reported obstetric anal sphincter injury (OASI) rates of 5.0% in nulliparous and 1.3% in multiparous women are remarkably, if not unacceptably high. Particularly, given the risk for serious, often untreatable complications strongly associated with such injury.The reported event rates in the pool study are an outlier when compared to the 1.6% reported in other studies.3 The reported rates in the POOL study are comparable to those reported by Gurol-Urganci et al.4 Nonetheless, 20% of the women in the Gurol-Urganci et al study had operative vaginal births, a strong risk factor for OASI. In contrast, the POOL study cohort were all low-risk spontaneous births.The POOL study describes women delivering in and out of water, but the authors do not comment if manual perineal protection was used or not in either of the groups. Applying interventions, like manual perineal protection at the time of water birth may be challenging and does not tend to be attempted in some healthcare settings.Manual perineal protection was earlier associated with a significant reduction in OASI risk in Norway and Denmark and the UK. Fodstad et al. describe that the OASI prevalence in Norway in all vaginal deliveries has reduced from 4.2% in 2004 to 1.6% in 2023, after introduction of a national program with manual perineal protection.3Gurol-Urganci et al. have also demonstrated a significant reduction OASI rates in a healthcare setting comparable to that of Saunders et al. Moreover, the RCOG and, more recently, the published report from the All-Party Parliamentary Group on Birth Trauma have recommended the roll out and implementation, underpinned by sufficient training, of the OASI care bundle to all hospital trusts to reduce risk of perineal injuries in childbirth.4 Hence, it would have been expected that a UK based study using perineal trauma as its primary outcome would address and discuss what interventions were undertaken to mitigate the risk of trauma.We believe that there is a high risk that the exceptionally high OASI rate in the comparator arm has introduced bias in this non-inferiority RCT. Sanders et al conclude that their “Study findings provide reassurance that birth in water, in the context of UK midwifery practice, is not associated with increased risks for mothers or their babies. However, given the 2015 Supreme Court Montgomery ruling stating that “clinicians should disclose risks of childbirth” one should question, why the risk of childbirth in the POOL study was so unacceptably high and still remained undiscussed?Jan Willem de Leeuw, Department of Obstetrics and Gynaecology, Ikazia Ziekenhuis Rotterdam, the NetherlandsKatariina Laine, Norwegian Research Centre for Women’s Health, Oslo University Hospital, Oslo, Norway, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, NorwayMargareta Manresa, Clinic Institute of Gynaecology, Obstetrics and Neonatology, Hospital Clinic of Barcelona, Barcelona, SpainSari Raisanen, Laurea University of Applied Sciences, Vantaa, FinlandVladimir Kalis, Department of Obstetrics and Gynaecology, Faculty of Medicine in Pilsen, Charles University, Center for Pelvic-floor Disorders, Pilsen, CzechiaZdenĕk Rušavý, Department of Obstetrics and Gynaecology, Faculty of Medicine in Pilsen, Charles UniversityRenaud de Tayrac, Obstetrics and Gynaecology Department, Nimes University Hospital, University of Montpellier, Nimes, France

Abdul Sultan

and 1 more

Episiotomy and operative vaginal delivery- Do we need more evidence?A.H. Sultan- Urogynaecology and Pelvic Floor Reconstruction Unit, Croydon University Hospital, London Road, Croydon CR7 7YE- Honorary Reader, St George’s University of LondonEmail:[email protected]: 00 44 7961386840(ORCID 0000-0001-8979-2304)J.W. de Leeuw, Department of Obstetrics and Gynaecology, Ikazia Ziekenhuis, Rotterdam, the Netherlands(ORCID 0000-0001-5028-8055)DISCLOSURE of INTERESTAbdul Sultan is the co-director of the Croydon Perineal and Anal Sphincter Trauma courses (www.perineum.net)Operative vaginal delivery (OVD) is recognised as a major risk factor in the occurrence of obstetric anal sphincter injuries (OASIs), particularly during first vaginal deliveries. Randomised controlled trials (RCTs) have shown the merits of adopting a policy of restrictive mediolateral episiotomy during normal vaginal delivery, although no RCT to date has included measurements of the angle or size of the episiotomy. The benefits of episiotomy performed during OVD demonstrated in large observational studies are overwhelming (Sultan et al. Eur J Obstet Gynecol Reprod Biol. 2019;240:192-196) .Ankarcrona et al have added another study to this collection and have confirmed the results of most such publications. In their study, based on 11 years of data from the Swedish Medical Birth Register, they have emulated a RCT using propensity scores. Ultimately, both methods used showed an almost identical risk reducing effect as the commonly used logistic regression analysis. demonstrating a significant reduction in OASIs during vacuum extraction associated with the use of mediolateral or lateral episiotomies. The Number Needed to Treat to prevent one OASI was 27, which is known to be fourfold lower in forceps delivery.Is the episiotomy a treatment for a certain condition or disease? In reality, episiotomy is an intervention to reduce the risk for an unwanted side effect of birth. Consequently, the impact is one of risk modification as opposed to treatment. Similar to the study by Ankarcrona et al risk factors are commonly established with the use of observational studies (RCOG Greentop guideline No 29, 2015) . In the last decade, several large observational studies Involving more than 2 million women showed a significantly lower rate of OASI in nulliparous women undergoing OVD with an episiotomy.Given the availability of such studies, based on registered databases, showing significantly lower OASI rates, is there still a need for further evidence? Ankarcrona et al acknowledge Lund et al who have shown in their systematic review that there is an association between the risk reduction for OASI with episiotomy rates; the greatest reduction was shown in studies with episiotomy rates over 70%.Obstetricians opposing the use of routine episiotomy during OVD highlight the lack of a definitive RCT. RCT’s are commonly used to address the treatment effect of an intervention on a particular condition with a well described outcome. However, RCT’s of episiotomy during OVD have proven to be very difficult and usually compare no more than the liberal versus the restricted use of episiotomy. As Ankarcrona et al mention, there is only one pilot RCT of IVD and episiotomy indicating that 1600 OVD will need to be included for a definitive study. However, we believe that the design of such a study should be two separate arms for forceps and vacuum delivery as the inherent risks with/without an episiotomy is different. Such a study with vacuum extraction is currently underway in Sweden.The challenge now is to identify prior to labour which women are at high risk of sustaining OASIS using prediction models based on the pre-existing large national databases.