Pre-operative anaemia in women undergoing caesarean section
M Ferguson,1,2 S Jackson,2 AT Dennis1,2
1Royal Women’s Hospital, Parkville, Australia; 2The University of Melbourne, Parkville, Australia
Caesarean section (CS) is a common global surgical procedure with nearly 23 million procedures annually. The peri-operative mortality in high income countries (HIC) is low, but bleeding >1500 ml occurs in approximately 2.6%. CS could therefore be considered a moderate risk significant surgical procedure. Undergoing significant surgery is associated with adverse outcomes in non-pregnant females with haemoglobin (Hb) levels <120 g.l-1. Recent recommendations advise that all patients with anaemia (Hb <130 g.l-1), regardless of sex, should be investigated and treated to normalise Hb levels preoperatively. It is unclear how this recommendation translates to pregnant women where anaemia is defined at a much lower Hb level (<110 g.l-1), likely the result of flawed sampling of an anaemic so called “normal” female population. There is no published information regarding peri-operative risk in pregnant women with Hb levels <130 g.l-1.
The aim of this study was to determine the prevalence of Hb levels <130 g.l-1 in women prior to CS, and to determine lowest postoperative, and discharge haemoglobin levels.
After institutional ethics approval we conducted a 12- week study of all women undergoing caesarean section in a tertiary referral high income country hospital. Serial antenatal (first Hb), pre–operative (Hb prior to CS), lowest postoperative (Day 1) and discharge (Day 2) Hb levels were recorded.
470 women underwent CS. Mean ± SD age and body mass index were 33 ± 5.2 years and 26 ± 5.9 kg.m-2 respectively. Antenatally, the median (IQR) Hb was 128 g.l-1 (120-135 g.l-1, median 7weeks gestation). Antenatal anaemia prevalence (Hb <130 g.l-1) was 57%. Pre-operatively, the median Hb was 125 g.l-1(116-132 g.l-1, median 39 weeks gestation). Pre-operative anaemia prevalence (Hb <130 g.l-1) was 67%. Postoperatively, the median lowest Hb and discharge Hb were 107 g.l-1 (97-117 g.l-1) and 108 g.l-1 (98-117 g.l-1), respectively. Postoperative anaemia prevalence (Hb <130 g.l-1) was 95% among patients who had discharge Hb measured (n=193).
Most women undergoing CS, postoperatively and at hospital discharge were anaemic. Non-pregnant non-anaemic females need to be followed throughout pregnancy to determine healthy pregnancy Hb reference ranges. Large prospective studies, including low middle income countries, are needed to determine outcomes after CS in women stratified by pre-operative Hb levels.