Variation in rates of caesarean section among English NHS trusts after accounting for maternal and clinical risk: cross sectional study

Overuse of a potentially harmful intervention, or underuse of one
that may be beneficial, are both undesirable situations. Excessive
variation in caesarean section (CS) rates across NHS hospitals in England,
as reported by Briggs et al(1), is thus a cause for concern.

Of particular note, is the fact that most of the variation in the CS
rates was related to the 89,834 emergency caesarean sections, rather than
elective procedures. If, as expected, fetal distress and dystocia were the
reasons given for most of these emergency procedures, it follows that
these two poorly defined intrapartum conditions were responsible for most
of the variation in CS rates across NHS hospitals in England. Furthermore,
if adjusting for fetal distress and dystocia eliminated a "North - South"
divide that otherwise existed with unadjusted data, questions over the
possible existence of a "North - South" divide in relation to fetal
distress and dystocia should be asked. On a technical note, I wonder if
adjusting for these two conditions, fetal distress and dystocia, was
required in the first place since both were precursors to, and may hence
have been present in nearly all emergency caesarean sections.

There is a potential role for systems such as the Robson groups
classification(2, 3) in comparing CS rates, not only within the same unit
over time, but between units too. Unlike analyses that use sometimes
poorly defined clinical diagnoses, the Robson groups classification uses
prospectively identifiable, simple, clearly defined, and clinically
relevant patient characteristics(2). One of the benefits of this system
has been the clear demonstration that primary caesarean sections (CS in
first time mothers) and repeat caesareans account for the largest
proportions of caesareans in the UK, whilst mothers who achieve a vaginal
delivery in their first childbirth are very unlikely to end up with a
caesarean next time(2). Such valuable information emphasises the need to
pay particular attention to the first labour, as its outcome greatly
determines the future method of delivery for that woman. That some of the
data items required for the Robson groups analysis are unavailable from
HES data is surprising since all of the items are available on the
existing local maternity information systems used in the UK.

References

1. Bragg F, Cromwell DA, Edozien LC, Gurol-Urganci I, Mahmood TA,
Templeton A, van der Meulen JH. Variation in rates of caesarean section
among English NHS trusts after accounting for maternal and clinical risk:
cross sectional study. BMJ 2010 341:c5065; doi:10.1136/bmj.c5065

2. Robson MS. Classification of Caesarean Sections. Fetal and
Maternal Medicine Review 2001; 12:23-39.

3. Thomas J, Paranjothy S. National sentinel caesarean section audit
report. RCOG Press, 2001.