Beyond term, the risks of stillbirth or neonatal death increase. It is unclear whether
a policy of labour induction can reduce these risks. This Cochrane review is an update
of a review that was originally published in 2006 and subsequently updated in 2012
To assess the effects of a policy of labour induction at or beyond term compared with
a policy of awaiting spontaneous labour or until an indication for birth induction
of labour is identified) on pregnancy outcomes for infant and mother. We searched
Cochrane Pregnancy and Childbirth’s Trials Register, ClinicalTrials.gov and the
WHO International Clinical Trials Registry Platform ( ICTRP ) (9 October 2017), and
reference lists of retrieved studies. Randomised controlled trials (RCTs) conducted
in pregnant women at or beyond term, comparing a policy of labour induction with a
policy of awaiting spontaneous onset of labour (expectant management). We also included
trials published in abstract form only. Cluster‐RCTs, quasi‐RCTs and trials using
a cross‐over design are not eligible for inclusion in this review. We included pregnant
women at or beyond term. Since a risk factor at this stage of pregnancy would normally
require an intervention, only trials including women at low risk for complications
were eligible. We accepted the trialists' definition of 'low risk'. The trials of
induction of labour in women with prelabour rupture of membranes at or beyond term
were not considered in this review but are considered in a separate Cochrane review.
Two reviewers independently assessed trials for inclusion, assessed risk of bias and
extracted data. Data were checked for accuracy. We assessed the quality of evidence
using the GRADE approach. In this updated review, we included 30 RCTs (reporting on
12,479 women). The trials took place in Norway, China, Thailand, the USA, Austria,
Turkey, Canada, UK, India, Tunisia, Finland, Spain, Sweden and the Netherlands. They
were generally at a moderate risk of bias. Compared with a policy of expectant management,
a policy of labour induction was associated with fewer (all‐cause) perinatal deaths
(risk ratio (RR) 0.33, 95% confidence interval (CI) 0.14 to 0.78; 20 trials, 9960
infants; moderate‐quality evidence). There were two perinatal deaths in the labour
induction policy group compared with 16 perinatal deaths in the expectant management
group. The number needed to treat to for an additional beneficial outcome (NNTB) with
induction of labour in order to prevent one perinatal death was 426 (95% CI 338 to
1337). There were fewer stillbirths in the induction group (RR 0.33, 95% CI 0.11 to
0.96; 20 trials, 9960 infants; moderate‐quality evidence); there was one stillbirth
in the induction policy arm and 10 in the expectant management group. For women in
the policy of induction arms of trials, there were fewer caesarean sections compared
with expectant management (RR 0.92, 95% CI 0.85 to 0.99; 27 trials, 11,738 women;
moderate‐quality evidence); and a corresponding marginal increase in operative vaginal
births with induction (RR 1.07, 95% CI 0.99 to 1.16; 18 trials, 9281 women; moderate‐quality
evidence). There was no evidence of a difference between groups for perineal trauma
(RR 1.09, 95% CI 0.65 to 1.83; 4 trials; 3028 women; low‐quality evidence), postpartum
haemorrhage (RR 1.09 95% CI 0.92 to 1.30, 5 trials; 3315 women; low‐quality evidence),
or length of maternal hospital stay (average mean difference (MD) ‐0.34 days, 95%
CI ‐1.00 to 0.33; 5 trials; 1146 women; Tau² = 0.49; I² 95%; very low‐quality evidence).
Rates of neonatal intensive care unit (NICU) admission were lower (RR 0.88, 95% CI
0.77 to 1.01; 13 trials, 8531 infants; moderate‐quality evidence) and fewer babies
had Apgar scores less than seven at five minutes in the induction groups compared
with expectant management (RR 0.70, 95% CI 0.50 to 0.98; 16 trials, 9047 infants;
moderate‐quality evidence). There was no evidence of a difference for neonatal trauma
(RR 1.18, 95% CI 0.68 to 2.05; 3 trials, 4255 infants; low‐quality evidence), for
induction compared with expectant management. Neonatal encephalopathy, neurodevelopment
at childhood follow‐up, breastfeeding at discharge and postnatal depression were not
reported by any trials. In subgroup analyses, no clear differences between timing
of induction (< 41 weeks versus ≥ 41 weeks' gestation) or by state of cervix were
seen for perinatal death, stillbirth, NICU admission, caesarean section, or perineal
trauma. However, operative vaginal birth was more common in the inductions at < 41
weeks' gestation subgroup compared with inductions at later gestational ages. The
majority of trials (about 75% of participants) adopted a policy of induction at ≥
41 weeks (> 287 days) gestation for the intervention arm. A policy of labour induction
at or beyond term compared with expectant management is associated with fewer perinatal
deaths and fewer caesarean sections; but more operative vaginal births. NICU admissions
were lower and fewer babies had low Apgar scores with induction. No important differences
were seen for most of the other maternal and infant outcomes. Most of the important
outcomes assessed using GRADE had a rating of moderate or low‐quality evidence ‐ with
downgrading decisions generally due to study limitations such as lack of blinding
(a condition inherent in comparisons between a policy of acting and of waiting), or
imprecise effect estimates. One outcome (length of maternal stay) was downgraded further
to very low‐quality evidence due to inconsistency. Although the absolute risk of perinatal
death is small, it may be helpful to offer women appropriate counselling to help choose
between scheduled induction for a post‐term pregnancy or monitoring without (or later)
induction). The optimal timing of offering induction of labour to women at or beyond
term warrants further investigation, as does further exploration of risk profiles
of women and their values and preferences. Individual participant meta‐analysis is
likely to help elucidate the role of factors, such as parity, in influencing outcomes
of induction compared with expectant management. Induction of labour in women with
normal pregnancies at or beyond term What is the issue? A normal pregnancy lasts about
40 weeks from the start of the woman's last menstrual period, but anything from 37
to 42 weeks is considered as being at term (within the normal range). If a pregnancy
goes too long, a woman and her clinician may wish to intervene to bring the birth
on, for example, by induction. Why is this important? Births after 42 weeks' gestation
may slightly increase risks for babies, including a greater risk of death (before
or shortly after birth). However induction of labour may also have risks for mothers
and their babies, especially if women are not ready to labour. No tests can predict
if babies would be better to stay inside their mother or if labour should be induced
to make the birth happen sooner. Many hospitals therefore have policies for how long
pregnancies should continue. This update (originally published in 2006 and subsequently
updated in 2012) looks to see if inducing labour at a set time at or beyond term,
could reduce risks for the babies. What evidence did we find? We searched for evidence
up 9 October 2017 and identified 30 trials with over 12,000 women. The trials took
place in Norway, China, Thailand, the USA, Austria, Turkey, Canada, UK, India, Tunisia,
Finland, Spain, Sweden and the Netherlands. The evidence was mostly of moderate quality.
The trials compared a policy to induce labour at or later than term (usually after
41 completed weeks of gestation (> 287 days)) with waiting for labour to start and/or
waiting for a period before inducing labour. We found that there were fewer deaths
of babies in hospitals with a policy to induce when a pregnancy was continuing beyond
term (moderate‐quality evidence). Fewer caesarean births were required with induction
compared with waiting, but more assisted vaginal births were required with induction.
There were fewer admissions to the intensive care nursery and fewer low Apgar scores
at five minutes after birth (a simple test to test babies' health) in the induction
groups compared with waiting (moderate‐quality evidence). We found that there were
no clear differences between a policy to induce at or later than term or waiting in
the risks of mothers having trauma to their perineum or bleeding after birth (both
low‐quality evidence), in the length of their hospital stay (very‐low quality evidence),
or in their babies having trauma (low‐quality evidence), None of the trials provided
information on breastfeeding at discharge from hospital, postnatal depression, or
whether the babies had encephalopathy (early abnormal neurological function), or child
development. What does this mean? A policy of labour induction compared with expectant
management is associated with fewer deaths of babies and fewer caesarean sections;
but more assisted vaginal births. Although the chances of babies dying are small,
it may help to offer women appropriate counselling to make an informed choice between
induction of labour for pregnancies at, or later than, term ‐ or waiting for labour
to start and/or waiting before inducing labour. The best time to offer induction of
labour to women at or beyond term is not yet clear and warrants further investigation.
The risk profiles of women as well as their values and preferences could also be considered.