Perineal trauma and OASIS — structured oral station (12 minutes)

Opening prompt — "Explain to her what happened at her birth."

Model response — plain words first, jargon second: ^[1][3]

• Sit down, at her level, and check what she already understands before you explain anything.
• "During the birth, the tear went further back than the skin and muscle of the perineum. It reached the ring of muscle around the back passage. There are actually two rings — an inner one that works automatically and holds things in when you are not thinking about it, and an outer one you can squeeze. In your case both rings were torn. That is what we call a third-degree tear, grade 3c."
• "It was repaired in the operating theatre the same night by a consultant, with the layers stitched separately. That is the right way to do it."
• "The symptoms you are describing — urgency, and trouble holding wind — are directly related to that injury, particularly to the inner ring. You are not imagining them and you are not unusual."^[1][3]

Examiner is listening for: no jargon before explanation, the two-sphincter idea, explicit validation of the symptoms, and the word "wind" said out loud without embarrassment. ^[1]

Probe 1 — "She asks why hers was a 3c and not a 3a. What is the classification?"

• "Third-degree tears are graded by how much of the outer sphincter is torn. 3a is less than half its thickness, 3b is more than half, and 3c means the inner sphincter is torn as well. If the tear goes through into the lining of the back passage it becomes a fourth-degree tear."^[1]
• "If we are ever unsure between 3a and 3b, the rule is to grade it up, not down — because under-grading leads to under-repair and no follow-up."^[1]
• "Her grade matters clinically: injury to the inner sphincter is associated with worse defaecatory symptoms and worse manometry results than injury to the outer sphincter alone. That is precisely what she is experiencing."^[1][3]

Probe 2 — "Her endoanal ultrasound shows a persistent internal sphincter defect and her manometry shows a low resting pressure. What do you do?"

• "Those results are consistent with her symptoms and they change my advice about her next birth, so I would want them in her record and in her hands."^[1]
• "I would use a validated incontinence symptom score to quantify where she is now, so we can measure any change."^[1]
• "I would refer her — pelvic floor physiotherapy first, and to a urogynaecologist or colorectal surgeon given that she is symptomatic with a demonstrable defect. Secondary sphincteroplasty exists for the woman who fails conservative management, but it is not the first step."^[1]
• "I would also be honest that a residual sonographic defect after repair is common — reported in roughly a fifth to a third of women — and that in an asymptomatic woman its significance is unclear. In her case it is not asymptomatic, which is why it matters."^[1][2]

Probe 3 — "She asks whether she should have a caesarean next time."

This is where candidates either over-promise or dodge. Do neither. ^[4][5]

• "Because you have symptoms and your tests are abnormal, I would offer you a planned caesarean, and that is the guideline position — it is offered to women who are symptomatic or who have abnormal ultrasound or pressure studies, rather than to everyone who has had this injury."^[1]
• "If you chose another vaginal birth, the chance of tearing in the same way again is about 5 to 7 percent. That is higher than average but it is not the majority."^[1]
• "I want to be honest about what a caesarean does and does not do. It protects you from a new sphincter injury. It does not undo the damage that has already happened, and when this has been studied properly the protection against future bowel symptoms is smaller than most people assume."^[4][5]
• "There is also no evidence that cutting an episiotomy next time would prevent a recurrence, so I would not plan one for that reason alone."^[1]
• "This is your decision. I will document whatever we agree, and you can change your mind later in the pregnancy."^[1]

Probe 4 — "Her partner asks whether this will ever get better."

• "Most women do well: 60 to 80 percent are free of symptoms a year after this repair. She is 10 weeks out, so there is still improvement to come, particularly with physiotherapy."^[1]
• "I would not overstate it either. Pooled data show a real excess of bowel symptoms after this injury compared with women who did not have it, and long-term cohort follow-up shows measurable differences even two decades later. Some women live with a degree of this, and there are treatments for that."^[3][6]
• Ask, out loud, about the things she has not raised: pain with sex, mood, fear of the next birth, and whether she has felt able to talk to anyone about it.^[1]

Probe 5 — "How could this injury have been prevented?"

• "I would name the perineal care bundle: a warm compress in the second stage; a slow controlled birth with hands-on perineal support; a correctly angled mediolateral episiotomy at crowning at a minimum of 60 degrees when one is indicated, and offered to a nulliparous woman having a forceps or ventouse birth; a routine examination including a rectal examination after every birth; and grading against the RCOG scale confirmed by a second clinician."^[1]
• "The stepped-wedge evaluation of the care bundle showed a modest but real reduction, from 3.3 percent to 3.0 percent overall. It is a small absolute effect across a whole population, not a guarantee for any individual."^[1]
• "And I would say clearly to her that a tear at forceps birth in a first baby with an occipitoposterior position and a big baby is not a failure of her care — the risk factors are strong and they do not allow us to predict who will tear."^[1]