Factors Associated With the Onset of Chronic Headaches in Patients Who Received a Blood Patch in Post Partum

It is established that accidental dural puncture promotes the onset of chronic headaches in 25 to 60% of cases but the risk factors for the occurrence of this event are not known. To identify those risk factors, the investigators will analyze the initial conditions of the accidental breach, the initial manifestations of the PDPH, the methods of carrying out the BP and the patient data. In this study, the investigators will evaluate (phone questionnaire and score) incidence of chronic headaches at 1 month and 6 months after the realization of a blood patch, incidence of chronic low back pain, impact on daily life, incidence of late recurrences of PDPH, incidence of early and distant complications In case of failure of effectiveness of the first blood patch, the investigators will search for associated factors: patient data, mode of delivery, initial PDPH, conditions for carrying out the BP.