The main purpose of the study is to evaluate the effectiveness and safety of the impedance spectroscopy device prototype in the detection of anal sphincter injuries in women in the early postpartum period. The study is prospective. The study group comprises up to 56 patients; up to 16 weeks from a natural delivery. The planned participation of each patient in the study is up to 4 weeks and two visits will take place at that time.

After obtaining written consent, at the first visit (V1) each patient will undergo a physical examination (both proctological and gynecological examination), blood samples for laboratory tests and stool samples for calprotectin concentration assessment will be collected. The presence of clinical symptoms of both gas and stool incontinence will be assessed during the visit with the use of Wexner's scale. Then, the dates of two reference tests will be planned: Trans-rectal USG and Recto-anal manometry which will be performed as part of the V1 visit within a period not exceeding 27 days.

The V2 visit, which will also be the final visit, will include a reassessment of the patient's general condition, recording the values of basic vital parameters, subjective and physical examination, and then the doctor conducting the examination will finally determine the extent of sphincter damage, present the patient with therapeutic options and decide on the treatment or rehabilitation of sphincter.

During the visits, all adverse events will also be monitored, both those reported by patients and those related to the examined diagnostic device.

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.