Spontaneous vaginal delivery of a healthy infant provokes a unique surge in stress hormone concentrations (e.g. AVP (arginine vasopressin) /copeptin) incommensurable with child or adult levels measured in any other situation. In contrast, infants delivered by primary caesarean section without preceding labour have low stress hormone concentrations at birth unless other stressors are present, including chorioamnionitis or intrauterine growth restriction. Infants delivered by caesarean section after a trial of labour show copeptin concentrations between these two extremes.

Objectives:1) To reduce neonatal respiratory morbidity and admission to the Neonatal Intensive Care Unit and increase bonding and breastfeeding by triggering uterine contractions prior to planned caesarean delivery.

2) To collect prospectively weight data of infants in the first 6 months of life to validate and expand our online neonatal weight calculator.

Study design: Open label; randomised, placebo controlled trail Intervention: Oxytocin challenge test (OCT): Infusion of oxytocin 5 IU/500 ml Ringer® lactate at a rate of 12 ml/h and doubled every 10 min until three uterine contractions per 10-min interval are induced, at which point it will be stopped.

Primary endpoint:

- Incidence of neonatal respiratory morbidity

Secondary endpoints:

• Umbilical cord blood copeptin levels
• Postnatal neonatal weight change
• Breastfeeding status

Inclusion Criteria:

• Singleton pregnancy >34 weeks
• primary caesarean section, that is without preceding contractions or rupture of the membranes,
• absence of a contraindication to oxytocin

Exclusion Criteria:

• Chromosomal aberration
• malformation,
• IUGR,
• Nonreassuring fetal heart rate pattern,
• Placenta praevia,
• maternal substance abuse,
• infections,
• hypertension,
• preeclampsia,
• diabetes type I or II,
• autoimmune disease (antiphospholipid syndrome, lupus erythematosus, etc.),
• renal disease,
• history of more than one previous caesarean section.