Outcomes of Induction of Labour in Women with Previous Caesarean Delivery: A Retrospective Cohort Study Using a Population Database
et al. (2013) Outcomes of Induction of Labour in Women with Previous Caesarean Delivery: A
Retrospective Cohort Study Using a Population Database. PLoS ONE 8(4): e60404. doi:10.1371/journal.pone.0060404
Outcomes of Induction of Labour in Women with Previous Caesarean Delivery: A Retrospective Cohort Study Using a Population Database
Sarah J. Stock 0
Evelyn Ferguson 0
Andrew Duffy 0
Ian Ford 0
James Chalmers 0
Jane E. Norman 0
Philippa Middleton, The University of Adelaide, Australia
0 1 MRC Centre for Reproductive Health, University of Edinburgh , Edinburgh , United Kingdom , 2 NHS Lanarkshire Department of Obstetrics and Gynaecology, Wishaw General Hospital , Wishaw , United Kingdom , 3 Information Services Division, NHS National Services Scotland , Edinburgh , United Kingdom , 4 Robertson Centre for Biostatistics, University of Glasgow , Glasgow , United Kingdom
Background: There is evidence that induction of labour (IOL) around term reduces perinatal mortality and caesarean delivery rates when compared to expectant management of pregnancy (allowing the pregnancy to continue to await spontaneous labour or definitive indication for delivery). However, it is not clear whether IOL in women with a previous caesarean section confers the same benefits. The aim of this study was to describe outcomes of IOL at 39-41 weeks in women with one previous caesarean delivery and to compare outcomes of IOL or planned caesarean delivery to those of expectant management. Methods and Findings: We performed a population-based retrospective cohort study of singleton births greater than 39 weeks gestation, in women with one previous caesarean delivery, in Scotland, UK 1981-2007 (n = 46,176). Outcomes included mode of delivery, perinatal mortality, neonatal unit admission, postpartum hemorrhage and uterine rupture. 40.1% (2,969/7,401) of women who underwent IOL 39-41 weeks were ultimately delivered by caesarean. When compared to expectant management IOL was associated with lower odds of caesarean delivery (adjusted odds ratio [AOR] after IOL at 39 weeks of 0.81 [95% CI 0.71-0.91]). There was no significant effect on the odds of perinatal mortality but greater odds of neonatal unit admission (AOR after IOL at 39 weeks of 1.29 [95% CI 1.08-1.55]). In contrast, when compared with expectant management, elective repeat caesarean delivery was associated with lower perinatal mortality (AOR after planned caesarean at 39 weeks of 0.23 [95% CI 0.07-0.75]) and, depending on gestation, the same or lower neonatal unit admission (AOR after planned caesarean at 39 weeks of 0.98 [0.90-1.07] at 40 weeks of 1.08 [0.94-1.23] and at 41 weeks of 0.77 [0.60-1.00]). Conclusions: A more liberal policy of IOL in women with previous caesarean delivery may reduce repeat caesarean delivery, but increases the risks of neonatal complications.
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Competing Interests: The authors have declared that no competing interests exist.
Rates of caesarean section are increasing worldwide, with rates
of more than 32% in the USA [1]. Many women therefore embark
on pregnancy with a previous caesarean scar, and the optimal
delivery method in this scenario is uncertain. It is well documented
that the risks of caesarean section for women increase with
increasing numbers of caesarean deliveries. These include
potentially life-threatening complications including haemorrhage,
surgical complications and morbidly adherent placenta, [2,3].
Promoting vaginal birth after previous caesarean (VBAC) may
help avoid these complications in future pregnancy, but there are
risks, particularly for babies. A recent carefully designed
prospective restricted cohort study suggested that, when compared to
elective repeat caesarean section, attempting VBAC resulted in a
significantly greater risk of a composite measure of serious
morbidity and death for infants [4]. However, as elective repeat
caesarean delivery is usually performed before term, the women
having elective repeat caesarean section in Crowther et als study
delivered at a significantly earlier gestation than women
attempting VBAC (mean +/2 SD 38.8+/20.7 weeks gestation versus
40.0 +/21.1 weeks gestation). It is possible that the observed
differences in neonatal complications arose because of differences
in gestational age at birth, rather than the intended mode of
delivery, given that perinatal mortality and infant morbidity
increase with advanced gestation beyond term [57].
As we and others have shown, there is increasing evidence that,
in women without a previous caesarean delivery, expediting
delivery around term by means of induction of labour (IOL),
results in lower perinatal mortality and caesarean delivery rates
compared to the alternative of expectant management (allowing
the pregnancy to continue to await spontaneous labour or
definitive indication for delivery) [8,9]. However, there are
particular concerns about induction of labour in women with a
previous caesarean section, with previous influential studies
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