• Nathan Riley, MD

Obgyno Wino Podcast Episode 30 - Prevention and Management of Perineal Lacs at Vaginal Delivery

Updated: Oct 23, 2019

"I think that we are becoming a culture that has lost its sense. It's in existential crisis. We don't even know what we are or what we're doing anymore. It's just 'wake up in the morning and figure out how to make more money'. There's going to be a lot to pay for because you can't afford to be a human being." - Thom Knoles, from his interview on the Under the Hood Podcast

2015 Pinot Noir from Franny Beck Wines

PB#198 - Published September 2018

Five Pearls

  1. Warm compresses or perineal massage may decrease likelihood of 3rd and 4th degree lacerations in some patients

  2. 1st and 2nd degree perineal lacerations can often be managed conservatively.

  3. Routine episiotomy is absolutely, without a doubt bad practice

  4. Ensure that you have adequate anesthesia before repairing vaginal injuries at time of delivery

  5. Carefully evaluate your patient for anal sphincter injuries, as these are associated with greatest risk of morbidity down the road

Female anatomy 101

External female genitalia

Classifying perineal lacerations

- 55-80% of women experience lacerations at time of delivery, most are 1st or 2nd degree

- 3rd and 4th degree lacs are also known as obstetric anal sphincter injuries (OASIS)

- special because they involve the anal sphincter

- in general, superficial perineal lacerations (1st or 2nd degree) don't have to be repaired unless they are bleeding heavily or the anatomy is significantly distorted

- same goes for other lacerations of the external genitalia

- OASIS should be repaired in order to restore function

- true incidence of OASIS is unclear due to inconsistencies and incompetence in evaluating for these types of injuries

- occult OASIS (sphincter injuries without clinical findings at time of delivery) are found 25% of the time after first vaginal deliveries by endoanal ultrasound

- risk factors for OASIS: operative vaginal delivery (forceps or vacuum), midline episiotomy, and increased fetal birth weight (less convincing risk factors: Asian descent, primiparity, labor induction, labor augmentation, epidural anesthesia, and posterior OP presentation)


- defined: when the birth attendee cuts the tissue in order to facilitate a vaginal delivery

- these are largely a thing of the past; if you find a practitioner that does them routinely, run in the opposite direction

- not even useful in managing shoulder dystocia

- mediolateral versus midline: the former carries greater risk of bleeding, pain, and healing complications; the latter heals faster and is easier to repair, but it carries greater risk of extension to OASIS

How do perineal injuries during vaginal delivery influence pelvic floor function?

- it's challenging to quantify and objectify the contribution of vaginal delivery to pelvic floor dysfunction

- episiotomy associated with higher rates of postpartum anal incontinence, regardless of extension to anal sphincter; rates even higher w/ OASIS

- 4th degree lacs carry highest risk of bowel control concerns 6 months postpartum (30% versus 3% for 3rd degree)

- cohort studies have found that spontaneous vaginal delivery and operative vaginal delivery (forceps >>> vacuum) are independent risk factors for the need for pelvic floor reconstructive surgery later in life, but contribution of episiotomy and perineal laceration is unclear

- furthermore, no association between perineal laceration/episiotomy and dyspareunia or pelvic pain 6-11 years after spontaneous vaginal delivery in primiparous patients

What can be done to prevent OASIS?

Perineal Massage

- digital perineal massage from 34 wks until delivery has been shown to decrease the likelihood of a perineal laceration that requires surgical repair

- performed in the 2nd stage of labor, it can reduce the risk of OASIS but not improve the overall likelihood of delivering over an intact perineum compared to "hands off" approaches

- insufficient evidence to guide the practice of supported head flexion prior to expulsion to prevent OASIS

Warm compresses

- performed in the 2nd stage of labor, it can reduce the risk of OASIS but not improve the overall likelihood of delivering over an intact perineum compared to "hands off" approaches

Pushing position

- upright or lateral positions carry decreased need for operative vaginal delivery but increased risk of 2nd degree lacs when compared to supine or lithotomy positions (though poor level of evidence)

- if the patient has an epidural, no difference between upright and supine groups

Delayed pushing

- no effect on perineal laceration rate (best evidence considered a delay of 1 to 3 hours)

Principles of repairing vaginal and perineal lacerations

- generally speaking, only repair periclitoral, periurethral, or labial lacerations if bleeding or anatomy distorted; if you do, use a #4-0 suture; use a catheter guide in the urethra to ensure that you don't suture closed the urethra

- according to ACOG, there's no difference in incontinence, sexual activity, or sexual function when comparing repair versus no repair of 1st or 2nd degree perineal lacerations

- if superficial and patient has no anesthesia, adhesive glue might be an option (no need for local!)

- if you need anesthetic 2% plain lidocaine should do the trick; don't be stingy!

How to repair a 2nd degree laceration

- #3-0 or #2-0 polyglactin or polydioxanone suture

- anchor beyond the apex of the laceration

- closed posterior defect in continuous fashion (I prefer non-locking method) to the hymenal remnant

- redirect needle by passing it posteriorly and exiting at the perineal body

- perform a crown stitch on either side of the laceration to re-approximate the bulbocavernous muscles (large bites are best!)

- reapproximate the subcutaneous tissue and muscle fibers of the superficial transverse muscles from anterior to posterior

- redirect needle to the apex of the skin laceration overlying the perineal body

- close the skin from posterior to anterior in subcuticular fashion

- redirect needle from in front of to behind the hymenal remnant

- anchor, cut sutures at level of knot

How to repair a 3rd degree laceration

- start with #3-0 polyglactin, #3-0 polydioxanone, or #2-0 polyglactin suture

- with a finger in the anus to guide the repair and ensure that you are not placing suture material through the intact anal mucosa, carefully close the internal anal sphincter in running fashion to the level of the external anal sphincter, tie this off

- then grasp both ends of lacerated external anal sphincter to bring them together at the perineal body

Note: end-to-end versus overlapping techniques of repairing external anal sphincter have been compared; no difference

- imagining the sphincter as a doughnut with a piece missing, re-approximate with #3-0 polyglactin or #3-0 polydioxanone suture the two separated ends with interrupted sutures at 3, 6, 9, and 12 o'clock (you can't be too thorough with this part)

- continue with 2nd degree laceration repair

How to repair a 4th degree laceration

- start with a #4-0 or #3-0 polyglactin suture

- close the rectal mucosa carefully using a finger in the anus as necessary to guide you

- continue with 3rd degree laceration repair

4th degree laceration

Should I administer prophylactic antibiotics after I repair lacerations?

- Available evidence suggests lower risk of wound complications if antibiotics administered at time of repair

- Reasonable to give a 1g dose of cefazolin

What are the risks of wound breakdown and complication postpartum?

- 25% chance of wound breakdown; 20% chance of infection

- perineal-rectal and rectal-vaginal fistulas are extremely rare (<2 in 100,000 women in 2006), but higher risk in undiagnosed or inappropriately repaired OASIS

- less fistulas noted in recent years compared to the past due to lower rates of operative vaginal delivery and episiotomies

How should women with OASIS be cared for?

- priorities: pain control, bowel management, and evaluation for urinary retention


- are opioids necessary? Probably not. Acetaminophen and ibuprofen are excellent and should be your mainstay. A low potency opioid should be made available (e.g. 2.5-5 mg hydrocodone + acetaminophen or oxycodone 2.5-5mg q3hr PRN)

- additionally, ice packs, sitz baths, and mentholated sprays can be soothing

Bowel management

- avoid constipation!

- stool softeners are useless (don't prescribe docusate to anybody's useless)

- gentle laxatives can be extremely helpful, especially if your patient is taking opioids, which agonize mu receptors in the gut in addition to the brain

- hydration, ambulation, and early PO intake

Urinary retention

- ensure that patient is peeing

- use bladder scans to ensure patient is voiding sufficiently postpartum

- straight catheterization or temporary indwelling foley catheteriziation if necessary

What are some longer term complications to look out for?

Bleeding: usually controlled with compression, but beware hematoma formation

Infection: may disrupt wound healing and can generally be managed conservatively, but beware abscess formation; occasionally intentional disruption of the repair may be required to treat the abscess; in very rare cases, necrotizing fasciitis can result, which can be life-threatening

Wound breakdown: superficial breakdown can generally be treated conservatively (i.e. healing by secondary intention); extensive breakdown may require primary closure (treat an infection first if present)

Should patients with OASIS be recommended c-section in subsequent deliveries?

- relative risk of OASIS in subsequent delivery is increased; absolute risk is low

- furthermore: "no differences in fecal urgency, anal incontinence, or bowel-related quality-of-life measures were demonstrated in women after a vaginal or cesarean delivery compared with before parturition"

- your counseling should thus include the increased morbidity with c-section compared to low absolute risk of morbidity associated with vaginal delivery after history of OASIS in prior delivery

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