Impedance Spectroscopy for Obstetric Anal Sphincter Injuries Detection

Inclusion Criteria: * women patients, * 18-49 years old, * up to 16 weeks from a natural delivery * with the presence of: 1. clinically confirmed OASIS at least stage II, as a result of an episiotomy or uncontrolled crotch rupture (in patients with crotch protection), or 2. at least one risk factor, such as: * the extended second delivery phase, * instrumental delivery (vacuum or forceps), * shoulder dystocia, * birth weight of the child \> 4kg, * episiotomy, * uncontrolled perineal laceration (in patients with crotch protection), * induction of delivery using oxytocin, * head circumference ≥34 mm and other. * the patient's understanding of the nature of the clinical study and permission in writing from the patient to participate in this study. Exclusion Criteria: * the presence of acute diseases during treatment, * the presence of chronic diseases not treated or treated insufficiently (e.g., incorrectly controlled hypertension), * the presence of diseases with accompanying symptoms of fecal incontinence history of proctology surgery's whit postoperative complication, * the presence of inflammatory bowel diseases during the exacerbation phase, * the treatment in the last year because of serious, progressive, uncontrolled cardiological, pulmonary, nephrology, contagious or psychiatric illness whose course could affect the patient's risk increase due to participation in the study, * significant disease symptoms so far undiagnosed, * the presence or suspected malignant disease or previous on previous oncological treatment in the last 5 years, * the presence of a cardiac stimulator or cardioverter-defibrillator, * severe surgery or severe trauma in the last year.