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

BMJ 2010; 341 doi: (Published 06 October 2010) Cite this as: BMJ 2010;341:c5065

Routinely recording women's weight would aid future analysis

Bragg et al discuss the limitation of under-reporting maternal
characteristics and obstetric conditions throughout NHS hospital episode
statistics, and mention 'obesity' as a specific example of this type of

The authors go on to suggest that in order for clinicians, patients
and policy makers to make greater use of maternity statistics, NHS trusts
should ensure that data is more complete.

They suggest starting with 'parity and gestational age', and I agree
that these are undoubtedly important and valid suggestions. However, I
would like to reiterate and emphasize the importance of including the
aforementioned example of 'obesity' too. NHS trusts would do well to begin
compiling standardized data on women's weight and/or body mass index, as
suggested by Callaway et al in 2006, particularly given the current fiscal
environment. "To assist in planning health service delivery, we believe
that BMI should be routinely recorded on perinatal data collection

We already know that in addition to growing numbers of overweight and
obese pregnant women in the UK, the number of morbidly obese women is
increasing too(2). We also know that overweight and obese women are more
likely to need a caesarean delivery.(3) Therefore, it makes sense to
record women's weight at the start of their pregnancy, and at various
stages throughout their pregnancy, both in terms of gathering and
analyzing data in relation to birth outcomes, and also as a means of
communicating timely and helpful advice to these women.

Previously, concerns have been raised about a blanket approach to
collecting data on women's weight, with calls for clear guidelines and
assurances that data would be collected and used consistently.(4) These
concerns need to be resolved without further delay, and progress made, so
that women can receive counseling about weight gain, nutrition, and food
choices, while at the same time being sensitively advised of some of the
possible increased risks - both to their babies and to themselves - that
are associated with excessive pre-pregnancy weight and/or weight gain
during pregnancy.(5)

This could have the dual advantage of providing researchers and the
NHS with more knowledge about the specific association between women's
weight and clinical risk, and (in cases where antenatal intervention is
successful) reducing women's risk of needing unwanted or emergency


(1) The prevalence and impact of overweight and obesity in an
Australian obstetric population. Callaway LK, Prins JB, Chang AM, McIntyre
HD. Med J Aust. 2006 Jan 16;184(2):56-9.

(2) A comparison of complications of pregnancy and delivery in
morbidly obese and non-obese women. Pathi A, Esen U, Hildreth A. J Obstet
Gynaecol. 2006 Aug;26(6):527-30.

(3) Obesity as an independent risk factor for elective and emergency
caesarean delivery in nulliparous women--systematic review and meta-
analysis of cohort studies. Poobalan AS, Aucott LS, Gurung T, Smith WC,
Bhattacharya S. Obes Rev. 2009 Jan;10(1):28-35. Epub 2008 Oct 23.

(4) The use of maternal weight measurements during antenatal care. A
national survey of midwifery practice throughout the United Kingdom. J
Eval Clin Pract. 1997 Nov;3(4):303-17. Ellison GT, Holliday M.

(5) Obesity in pregnancy. Davies GA, Maxwell C, McLeod L, Gagnon R,
Basso M, Bos H, Delisle MF, Farine D, Hudon L, Menticoglou S, Mundle W,
Murphy-Kaulbeck L, Ouellet A, Pressey T, Roggensack A, Leduc D, Ballerman
C, Biringer A, Duperron L, Jones D, Lee LS, Shepherd D, Wilson K; J Obstet
Gynaecol Can. 2010 Feb;32(2):165-73.

Competing interests: No competing interests

10 October 2010
Pauline M Hull