Page created on December 15, 2021. Last updated on January 17, 2022 at 18:55

Introduction

Multiple injuries may befall the mother during labour. The most common maternal obstetrical injuries include perineal ruptures, labial and vaginal lacerations, cervical injury, genital haematoma, nerve injuries, and uterine rupture (covered in topic A13).

Perineal rupture

Definition

During vaginal birth, the perineum may rupture, which constitutes the most common form of maternal obstetric injury. Most nulliparous women sustain a perineal injury during vaginal birth. These injuries are less common in multipara.

Etiology

Risk factors for this include:

• Nulliparity (first vaginal birth)
• Macrosomia
• Operative vaginal delivery
• Occiput posterior delivery

Classification

We classify perineal rupture into four degrees:

• 1^st degree – tear in skin only
• 2^nd degree – involvement of perineal muscles
• 3^rd degree – involvement of external anal sphincter
• 4^th degree – lesion of the anterior wall of the anal canal or rectum

Treatment

Treatment is surgical repair. After repair, digital rectal examination should be performed to evaluate. Laxatives should be used postoperatively to reduce the pressure on the surgical wound.

Prevention

The modified Ritgen manoeuvre can be used to reduce the risk of perineal injury. This involves using one hand to control the deflexion of the foetal head (so it doesn’t deflex too fast) and using the other hand to support the perineum and to “push” the chin of the foetus upwards though the perineum.

Application of warm compress to the perineum during delivery reduces the risk for perineal rupture and should be performed in all cases. In case of high risk for perineal rupture, a mediolateral or lateral (not median) episiotomy should be made to reduce the pressure on the perineum.

Complications

3^rd and 4^th degree perineal injury may cause faecal incontinence or formation of fistulae. Despite treatment, many patients remain faecally incontinent.

Labial and vaginal laceration

Lacerations of the labia and vagina are also common birth injuries. They are associated with operative delivery. Like the perineal injuries, we can classify them according to degrees of severity:

• 1^st degree – superficial laceration
• 2^nd degree – deeper laceration
• 3^rd degree – rupture of the posterior vaginal wall

Vaginal and rectal examination should be performed to rule out 3^rd degree laceration. Small lacerations usually don’t require definitive treatment, but larger ones may require suturing. If there are multiple lacerations, a tight vaginal pack with a catheter may be inserted to stop the bleeding.

Genital haematoma

Definition

A genital haematoma can occur if a concealed vessel (usually a varicose vein) starts to bleed adjacent to the genital tract. The haematoma often presents as a vulval swelling, or in the worst case as haemodynamic instability.

Clinical features

Haematomas usually cause vaginal or vulval swelling, and they can expand rapidly and be very painful and tender. The overlying skin has a purplish discoloration. Haematomas present 12 – 48 hours after of delivery.

Retroperitoneal haematomas may cause significant blood loss into the abdomen, potentially causing haemodynamic instability.

Treatment

Small, nonexpanding haematomas may be managed conservatively (ice packs, analgesics). Large or expanding haematomas should be treated with incision and evacuation. If retroperitoneal haematoma is suspected, the patient should undergo laparotomy.

Cervical injury

During birth, lacerations of the cervix may occur. Cervical injuries are associated with operative delivery and manual dilatation. Lacerations may bleed and may be palpable on examination. These are often minor and don’t require specific treatment. Deeper lacerations require surgical repair, usually in the operating theatre with anaesthesia.

Nerve injury

Multiple nerves may be injured during labour, but nerve injuries are rare in general. Nerves may be injured due to stretching, lumbar disc herniation, or prolonged compression of the nerve in the lithotomy position. Commonly injured nerves and their outcomes include:

• Peroneal nerve – foot drop
• Lumbar roots – foot drop, paraesthesia of the leg
• Pudendal nerve – incontinence, paraesthesia of the genital area and perineum