Costs and effects of induction of labour versus expectant management in women
with impending post-term pregnancies: the 41 week – 42 week dilemma.
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Post-term pregnancy is associated with increased perinatal morbidity and mortality and is considered as a high-risk stage which requires specialist surveillance and induction of labour at some stage. However, there is uncertainty in The Netherlands on the policy concerning the timing of induction for post-term pregnancy, leading to practice variation and strong debates between caregivers regarding pros and cons of labour induction for impending post-term pregnancy. To solve this dilemma in the Netherlands we propose a randomised trial to evaluate the effectiveness, costs and cost-effectiveness analysis of policy of labour induction at 41 weeks versus expectant management until 42 weeks in low risk women. We will study adverse perinatal outcome, adverse maternal outcomes, client satisfaction, preferences and costs.
Multicentre randomised controlled clinical trial with cost-effectiveness analysis.
Low risk women with a singleton pregnancy and a certain gestational age of 41 (-2/+2) weeks.
Labour induction at 41 weeks, if necessary proceeded by artificial cervical ripening, versus expectant management until 42 weeks.
The primary outcome will be a composite of perinatal mortality and neonatal morbidity. Adverse perinatal outcomes are defined as, a 5-minute Apgar-score below 7 and/or an arterial pH below 7.05, meconium aspiration syndrome, plexus brachialis injury, intracranial hemorrhage and/or NICU admission.
Secondary outcomes will be maternal outcomes: instrumental delivery (instrumental vaginal delivery, Caesarean section), pain treatment (epidural, remifentanyl, pethidin), hemorrhage and severe perineal injury (third- or fourth-degree perineal tear). Other outcomes are maternal experience of pain, maternal satisfaction and quality of life, client preferences for induction of labour or expectant management, and the extent to which these preferences are influenced by the attributes of obstetric care and socio-demographic factors.
The analysis will be by intention to treat. Based on the systematic review, we may anticipate that induction of labour will reduce the adverse perinatal outcome rate from 3% to 1%. We need a sample size of two groups of 825 women (1650 women) to achieve 80% power in rejecting the null hypothesis of no difference, using an alpha of a two-sided Z test with continuity correction.
We will collect data alongside the trial to estimate the costs and cost-effectiveness of immediate delivery and expectant management from the societal perspective.
Total study time is 48 months. Preparation time four months, recruitment 38 months, analysis and report six months.
Dr. E. de Miranda, midwife, AMC
Dr. B.W. Mol, gynecologist, AMC
Trialbureau Obs/Gyn Consortium
Dr. E. de Miranda
06-55532455 / 020-6963489