Interventions for preventing or improving the outcome of delivery at or beyond term.

BACKGROUND: Perinatal mortality and morbidity is increased in pregnancies of more than 42 weeks that are otherwise low risk.

OBJECTIVES: The objective of this review was to assess the effects of interventions aimed at either reducing the incidence or improving the outcome of post-term pregnancy.

SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register was searched.

SELECTION CRITERIA: Randomised and quasi-randomised trials of interventions involving the intention to induce labour at a specified gestational age.

DATA COLLECTION AND ANALYSIS: Eligibility and trial quality were assessed by one reviewer. Study authors were contacted for additional information.

MAIN RESULTS: Twenty-six trials of variable quality were included. There were four trials of routine early pregnancy ultrasound, two of nipple stimulation, nineteen of routine versus selective induction of labour and one of antenatal fetal monitoring. Routine early pregnancy ultrasound reduced the incidence of post-term pregnancy (odds ratio 0.68, 95% confidence interval 0.57 to 0.82). Breast and nipple stimulation at term did not affect the incidence of post-term pregnancy (odds ratio 0.52, 95% confidence interval 0.28 to 0.96). Routine induction of labour reduced perinatal mortality (odds ratio 0.20, 95% confidence interval 0.06 to 0.70). This benefit is due to the effect of induction of labour after 41 weeks. Routine induction of labour had no effect on caesarean section.

REVIEWER'S CONCLUSIONS: Routine early pregnancy ultrasound examination and subsequent adjustment of delivery date appear to reduce the incidence of post-term pregnancy. Routine induction of labour after 41 weeks gestation appears to reduce perinatal mortality. There is not enough evidence to evaluate the effects of breast and nipple stimulation, or tests of fetal wellbeing.