Forceps-Associated Maternal Trauma

Forceps associated maternal trauma is injury to the mother's genital tract and pelvic floor from forceps delivery, including third and fourth degree tears, vaginal and cervical lacerations, vaginal and vulval haematomas, urethral and bladder injury, and pelvic floor and sphincter damage. It is more frequent than in spontaneous births. It matters because it causes haemorrhage, infection, faecal and urinary incontinence, pain and sexual dysfunction.

• Risk factors: rotational forceps, high station, large baby, first labour, midline episiotomy, prolonged second stage, occiput posterior position.
• Mediolateral episiotomy lowers sphincter injury with forceps.
• Careful examination after every operative delivery finds hidden trauma.

Women have perineal pain, bleeding despite a firm uterus, an expanding vaginal or vulval mass, difficulty passing urine, or leaking stool or flatus. Examination shows a tear extending to or through the anal sphincter, or a laceration in the vagina or cervix.

• Heavy bleeding with a contracted uterus.
• Flatus incontinence and perineal pain.
• Differential diagnosis: uterine atony, retained placenta, vaginal haematoma, cervical laceration, uterine rupture, uterine inversion, coagulopathy.
• Complications: postpartum haemorrhage, anal sphincter injury with faecal incontinence, wound infection and breakdown, rectovaginal fistula, urinary retention, urethral or bladder injury, dyspareunia, chronic pain, pelvic organ prolapse, psychological distress.

The diagnosis is made by a systematic examination after birth with good light, analgesia and an assistant.

• Inspect the vulva, perineum, vagina and cervix; digital rectal examination to check the anal sphincter and rectal mucosa after every instrumental delivery.
• Grade the tear: first degree (skin only), second degree (perineal muscles), 3a (less than 50 percent external sphincter), 3b (more than 50 percent), 3c (internal sphincter), fourth degree (anal mucosa).
• Check for haematoma, urethral injury and bladder fullness; blood loss measured.
• Haemoglobin if bleeding was heavy.

The principle is to repair all tears in theatre with good light and analgesia, treat haemorrhage and prevent infection and constipation.

• Supportive: repair in lithotomy in theatre for third and fourth degree tears and cervical tears; ice packs for 24 hours; sitz baths twice daily; bladder catheter for 24 hours after sphincter repair; high fibre diet and fluids; pelvic floor exercises after healing; early review of women with incontinence.
• Pharmacological: lignocaine 1 percent 10 to 20 mL (maximum 3 mg/kg, not above 200 mg) infiltrated, or spinal or epidural for sphincter repair; cefazolin 2 g IV plus metronidazole 500 mg IV as a single dose at repair, then amoxicillin-clavulanate 625 mg oral 8-hourly for 5 to 7 days; lactulose 15 mL oral 12-hourly for 10 to 14 days (avoid constipation and straining); paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours) with diclofenac 50 mg oral 8-hourly for 3 days if no contraindication; oxytocin 10 IU IM after birth and 20 IU in 1 litre Ringer's lactate at 125 mL per hour for 4 hours; tranexamic acid 1 g IV over 10 minutes for bleeding above 500 mL.
• Procedures: repair of second degree tears with 2/0 or 3/0 polyglactin; anal sphincter repair by a trained operator, either end to end or overlap, with 3/0 polydioxanone or 2/0 polyglactin (internal sphincter repair with interrupted 3/0 sutures), and repair of the rectal mucosa with 3/0 polyglactin interrupted; cervical tear repair; drainage of haematoma.
• Special groups: women with a third or fourth degree tear are counselled that a later vaginal birth is possible if they have no symptoms and normal anal manometry, and elective caesarean section is offered if symptoms persist.
• Red flags: faecal leakage, wound breakdown, fever above 38 degrees Celsius, foul discharge, expanding vaginal mass, bleeding above 500 mL, inability to pass urine.
• Follow-up: wound review at 1 week; perineal and anorectal assessment at 6 weeks; referral for anal ultrasound and physiotherapy if incontinence persists; pelvic floor exercises for 3 months.