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.