Severe obstetric perinatal injuries, i.e. with complete EAS tear (Sultan classification grade IIIb-IV), are a relatively rare complication of vaginal delivery. In total, Sultan grade III-IV perineal tears occur in approximately 0.6-7% of vaginal deliveries (1-3), but these statistics also include grades IIIa and b with incomplete EAS tears. Despite advances in medical knowledge, severe obstetric damage to the perineum is still an only partially curable consequence of giving birth. Patients often struggle with symptoms of perineal tear, such as gas and faecal incontinence, as well as sexual problems, throughout their lives.

The Sultan classification, which has been adapted by the WHO, is commonly used to assess obstetric anal sphincter injuries (OASIS) (4). This is a progressive assessment tool considering the observed mechanism of complete perineal tear, including anal tear: initially, the superficial soft tissues (I) are damaged, followed by the perineal muscles (II), EAS (IIIa, b), IAS (IIIc), and finally the anorectal wall (IV).

Other types of injuries, such as damage to the levator ani muscles and isolated injuries to the rectum without sphincter complex (EAS and IAS) involvement, may also occur during delivery (5).

This type of trauma is not currently included in the commonly used Sultan classification (WHO), and therefore not recorded in a systematic manner. This type of damage will be discussed in this case report, where a rare adverse event in the form of avulsion (detachment) of the rectum from the anal canal and the intact external and internal sphincters occurred during physiological delivery.

A 28-year-old primiparous woman with unremarkable general and obstetric history reported for her first delivery. She had a normal pelvic structure, with perineal height of approximately 3 cm. The first stage of labour lasted about 6 hours. The patient did not receive epidural anaesthesia. The delivery progressed physiologically in a cephalic longitudinal position. During the second stage of labor, the patient was allowed to change body positions, including the knee-elbow position. The child’s cardiac function assessed after each contraction was normal, without pathological decelerations. After approximately 1 hour and 40 minutes of the second stage of labor, at the third rotation of the head (extension), the midwife noticed the crowning and clear fluid discharge from the anus. A doctor was called and, on visual inspection of the perineum, he noted the presence of the head in the anus, distended during uterine contraction. Local anaesthesia was immediately administered and right medio-lateral episiotomy was performed, after which, during the first contraction, a fetus weighing 3,000 g was delivered without difficulty (Apgar score 10, 10). The infant was not wrapped in the umbilical cord; the position was occiput anterior, physiological; and the shoulders were delivered properly.