Zarko Alfirevic (University of Liverpool), Peter Brocklehurst (NPEU), Jenny Kurinczuk (NPEU)
Severe maternal morbidity and mortality
Wellbeing of Women
True uterine rupture is a catastrophic event with significant associated maternal and fetal morbidity and mortality.
In the developed world it most commonly occurs in women who have previously delivered by caesarean section.
This observation has led to debate about the optimal management of labour and delivery in women who have delivered by caesarean section in previous pregnancies.
Women with a previous caesarean delivery have generally been encouraged to attempt a trial of labour in subsequent pregnancies, but recent reports of an increased risk of morbidity, particularly due to uterine rupture, are thought to have contributed to a marked decrease in the number of women attempting vaginal birth after caesarean section.
The aims of this study were to estimate the incidence of true uterine rupture in the UK and to investigate and quantify the associated risk factors and outcomes, based on intended mode of delivery.
The estimated incidence of uterine rupture was 2 per 10,000 maternities overall; 21 and 3 per 10,000 maternities in women with a previous caesarean delivery planning vaginal or elective caesarean delivery respectively.
Amongst women with a previous caesarean delivery, odds of rupture were also increased in women who had two or more previous caesarean deliveries (aOR 3.02, 95%CI 1.16-7.85) and less than 12 months since their last caesarean delivery (aOR 3.12, 95%CI 1.62-6.02).
A higher risk of rupture with labour induction and oxytocin use was apparent (aOR 3.92, 95%CI 1.00-15.33).
Two women with uterine rupture died (case fatality 1.3%, 95%CI 0.2-4.5%).
There were 18 perinatal deaths associated with uterine rupture among 145 infants (perinatal mortality 124 per 1000 total births, 95%CI 75-189).
This study shows that although uterine rupture is associated with significant mortality and morbidity, even amongst women with a previous caesarean section planning a vaginal delivery, it is a rare occurrence.
For women with a previous caesarean section, risk of uterine rupture increases with number of previous caesarean deliveries, a short interval since the last caesarean sectionand labour induction and/or augmentation, and these factors should be considered when counselling and managing the labour of women with a previous caesarean section.