Effect of Increased Oxytocin Doses on the Mode of Delivery in Obese Primiparous Women With Spontaneous or Induced Labour

Inclusion criteria Inclusion criteria are the following: * Age ≥ 18 years * Nulliparous (no previous childbirth beyond 22 SA) * BMI ≥ 30 kg/m² at the beginning of pregnancy * Singleton pregnancy * Spontaneous or induced onset of labour * Cephalic presentation * Term ≥ 37 weeks of gestation and \< 42 weeks of gestation * Medical Indication and absence of medical contraindication for oxytocin during labour: inadequate and/or ineffective uterine contraction and/or delayed cervical dilation * Written consent * Affiliation to a french social security system Exclusion criteria Exclusion criteria are the following: * Hypersensitivity to the active substance (oxytocin), to any of its excipients or to latex (risk of cross allergy) * Medical contraindication for oxytocin * Coagulation disorders * Foetal growth restriction (inferior to 5th percentile) * Foetal malformation (major) * Foetal heart rate anomalies before use of oxytocin (at the time of inclusion) * History of uterine surgery (scarred uterus of gynaecological origin) * Patient with a disease requiring caesarean section prior to labour (planned caesarean section before labour) * Severe renal failure * Patient deprived of their liberty (under curatorship or guardianship) * Participation in another interventional trial of category 1. Patients included in interventional research with minimal risk and constraints may participate in the study after the investigator's assessment.