Description

• Endometritis (infection of the endometrium) is the most common postpartum infection.
• Bacterial infection of genital tract, manifesting after delivery with a peak incidence at postpartum day 7. It can occur as late as 6 weeks postpartum.
• Postpartum infections of the myometrium and parametrial tissues are less common. Vaginal and cervical infections, perianal cellulitis, pelvic cellulitis, pelvic abscess, septic pelvic vein thrombophlebitis, and parametrial phlegmon are other (generally rare) postpartum infections of the pelvic region.
• System(s) affected: reproductive
• Synonym(s): postpartum infection; endometritis; endoparametritis; endomyometritis; myometritis; endomyoparametritis; metritis; metritis with pelvic cellulitis

Epidemiology

Prevalence

• Occurs after 1–3% of all births
• 10 times more likely after cesarean section
  • 2–15% of infections begin prior to labor.
  • 30–35% occur after labor in absence of appropriate antibiotic prophylaxis; 2–15% occur after labor with appropriate prophylaxis.
  • Fifth leading cause of maternal mortality, accounting for 11% of maternal deaths

Etiology and Pathophysiology

• Endometritis is more common in labors complicated by chorioamnionitis.
• Other infections follow trauma to the perineum, vagina, cervix, and uterus.
• Postpartum infections are typically polymicrobial, involving organisms ascending from the lower genital tract:
  • Aerobic isolates (70%): Streptococcus faecalis, Streptococcus agalactiae, Streptococcus viridans, Staphylococcus aureus, Escherichia coli
  • Anaerobic isolates (80%): Peptococcus sp., Peptostreptococcus sp., Clostridium sp., Bacteroides bivius, Bacteroides fragilis, Fusobacterium sp.
• Other genital Mycoplasma
• Consider herpes simplex virus and cytomegalovirus, particularly in immunocompromised patients failing to improve on appropriate antibiotics.
• Thrombosis of any pelvic vein, including vena cava
• Phlegmon on leaves of the broad ligament

Risk Factors

• Cesarean delivery is the primary risk factor.
• Chorioamnionitis
• Bacterial vaginosis, group B streptococcal colonization of genital tract
• HIV infection
• Prolonged labor, prolonged rupture of membranes; heavily meconium-stained amniotic fluid
• Multiple vaginal examinations, internal fetal monitoring during labor
• Episiotomy, 3rd or 4th degree perineal laceration, or other perineal trauma
• Operative vaginal delivery; manual extraction of the placenta; intrauterine balloon tamponade, care in a teaching hospital
• Inappropriately timed or delayed prophylactic antibiotics
• Low socioeconomic status, obesity, anemia

General Prevention

• Intrapartum prophylaxis for group B colonization of genital tract
• Vaginal delivery
  • Avoid unnecessary vaginal examinations.
  • Treat chorioamnionitis during labor.
  • Avoid manual placental extraction and retained placental products.
  • Aseptic technique for operative vaginal delivery
  • Consider prophylaxis with amoxicillin and clavulanic acid for operative vaginal delivery (1)[B].
  • Antibiotic prophylaxis for manual removal of the placenta has not been demonstrated to be effective.
• Cesarean delivery
  • Preoperative paint and scrub with 10% povidone-iodine or an alcohol-based solution decreases puerperal infection by up to 38%.
  • Prophylactic antibiotics before both emergency and scheduled cesarean deliveries prior to skin incision reduce postpartum infection (2)[A].
    • Administer antibiotics within 1 hour of the start of surgery (3). Repeat for lengthy procedures or excessive blood loss (3). Appropriate administration of antibiotics results in a 40% reduction in postpartum maternal infections without any increase in neonatal infections (2)[A],(3).
  • Extended coverage with cephalosporin and azithromycin further decreases infection risk and is cost-effective (3)[A].
  • Vaginal preparation with povidone-iodine solution or chlorhexidine-alcohol solutions immediately before cesarean delivery reduces the risk of postoperative endometritis.
  • Weight-based antibiotic dosage helps ensure appropriate tissue concentrations prior to skin incision.

Commonly Associated Conditions

• Chorioamnionitis
• Wound infection