The study looked at 382, 266 Danish women giving birth between 2001 and 2008. It compared the use of red blood cell transfusion within seven days of delivery to estimate the risk of PPH. Severe PPH is excessive blood loss following delivery.
Previous studies on the relation between actual mode of delivery and the risk of severe PPH show that caesarean delivery (CD) is associated with a higher risk. However this study looks at intended mode of delivery which may be more relevant both for obstetricians and women in their decision making say the authors.
Intended vaginal delivery included all vaginal deliveries and emergency caesarean sections.
The study compared the use of red blood cell transfusion by intended mode of delivery in the total population (382,266), in low risk first-time mothers (147,132), and in women with a previous caesarean delivery (25,156).
It found that compared to intended vaginal delivery, planned caesarean delivery is associated with a reduced risk of severe PPH.
Out of the total study population 7,335 (1.92%) received RBC transfusions within seven days of delivery.
The study found that amongst low risk first-time mothers the transfusion rate in the planned caesarean section group was significantly lower compared with the intended vaginal delivery group (1.24% versus 2.09%).
Women planning a caesarean delivery in their second pregnancy had a significant higher risk of receiving a RBC transfusion if they had a previous caesarean delivery compared to a previous vaginal delivery, with an odds ratio of 1.6. However, women intending a vaginal delivery after a previous caesarean section had an even higher risk, with an odds ratio of 3.29.
Charlotte Holm, Department of Obstetrics, Copenhagen University Hospital, and co-author of the paper said:
“The results of this study show that planned caesarean section can reduce the risk of severe post partum haemorrhage. These results may be useful in the counselling of pregnant women about the risks of bleeding in their first and second pregnancy.
“It should be emphasized, however, that individual risk assessment is still important and that the need of RBC transfusion is only one of several fetal and maternal factors that should be considered when choosing mode of delivery.”
Professor Philip Steer, Editor of BJOG added:
“This study looks at intended mode of delivery rather than actual delivery. This is important because emergency caesarean sections need to be seen as a complication of intended vaginal birth, rather than being included in the same group as elective caesareans.
“While women achieving a vaginal birth usually have the best outcomes, those whose labours end with an emergency caesarean face much higher risks than those having an elective caesarean. It is the fear of an unexpected emergency that drives some women to request elective caesareans when there is no obvious medical indication.”
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Please include a link to the paper in online coverage: http://dx.doi.org/10.1111/j.1471-0528.2011.03267.x
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Holm C, Langhoff-Roos J, Petersen KB, Norgaard A, Diness BR. Severe postpartum haemorrhage and mode of delivery: a retrospective cohort study. BJOG 2012; DOI: 10.1111/j.1471-0528.2011.03267.x.