Authors’ reply re: Assisted Vaginal Birth: Green-top Guideline No. 26.
Dear Editor
The challenge when counselling a woman about Assisted Vaginal Birth (AVB), and which instrument to use, encompasses a range of potential outcomes including early and late maternal and neonatal morbidity, and the implications for future births. Pelvic floor trauma is one important factor to consider and for those with a specialist interest in levator ani muscle avulsion it would seem obvious that assisted vaginal birth should be avoided whenever possible, and that vacuum should be preferred to forceps. 1 However, for circumstances where clinicians are attempting to avoid failed vacuum, subgaleal haemorrhage and second stage caesarean section, forceps may be preferred. In response to Dietz & Esegbona’s assertion that the guideline conveys a pro-forceps bias that does little to help clinicians make informed choices, exposing the RCOG to substantial medicolegal liability, we believe the guideline has provided balanced guidance for clinicians advising women on AVB. 2
Dietz and Esegbona find it “astounding” that the guideline and associated patient information leaflet “channel the state of the literature as it was over 10 years ago, especially since some of the most relevant literature was published in this journal.” Dietz cites three of his own publications including a BJOG publication from 2008 (12 years ago), and two systematic reviews of observational studies (many published over 10 years ago).
In preparation for the RCOG Guideline, a literature search was conducted by the college and included publications up to May 2019. A total of 149 publications were cited based on relevance and methodological quality, and at least 35 reported data on pelvic floor morbidity. A publication from 2015, addressing levator ani muscle injury, co-authored by Dietz, was included. 3
When comparing vacuum and forceps assisted delivery, the most reliable data are from randomised controlled trials and we cited the original Cochrane systematic review. 4 This review reported that vacuum assisted delivery was significantly less likely to be associated with significant maternal perineal and vaginal trauma than forceps (OR 0.4; 95% CI 0.3–0.5). We cited a further Cochrane review from 2010 that addressed choice of instrument and included additional RCTs that compared different types of vacuum device. 5The conclusion of this review was entirely consistent with the guideline.