A paper published in PLoS Medicine provides a novel method for estimating the risk of emergency caesarean section after a previous caesarean section. The authors, led by Professor Gordon Smith of the University of Cambridge, developed the method by analysing the outcome of over 11,000 women who attempted to give birth vaginally. They then tested the method in a separate sample of 11,000 women. They predicted that 36% had a low risk of caesarean section and 16.5% of women had a high risk. When the outcomes were compared, the rate of caesarean section was 10.9% among low risk women and 47.7% among high risk women.
The factors which were predictive of risk and used in the model were older maternal age, smaller height, male sex of baby, labour induced by prostaglandin, not having had a previous vaginal birth, and later birth.
Women at low predicted risk of emergency caesarean section were also at low risk of the most dangerous complication of attempting vaginal birth, a ruptured uterus.
Rates of caesarean section are rising worldwide. A major cause of this is that fewer women are attempting vaginal birth after caesarean section due to concerns regarding safety. This new method may provide a way of predicting those women who can safely attempt a vaginal birth after a previous caesarean section.
Public Library of Science. September 2005.