Description

• Endometritis (infection of the endometrium) is the most common postpartum infection.
• Bacterial infection of the genital tract, usually within the 1st week after delivery, but can occur 1–6 weeks postpartum
• Less common are postpartum infections of the myometrium and parametrial tissues, vaginal and cervical infections, perineal cellulitis, pelvic cellulitis, septic pelvic vein thrombophlebitis, and parametrial phlegmon.
• System(s) affected: Reproductive
• Synonym(s): Postpartum infection; Endometritis; Endoparametritis; Endomyometritis; Myometritis; Endomyoparametritis; Metritis; Metritis with pelvic cellulitis

Epidemiology

• Predominant age: Women of childbearing years
• Predominant sex: Female only

• Occurs in 1–3% of all births
• 10 times more likely with cesarean section:
  • 2–15% prior to labor
  • 30–35% after labor without prophylaxis
  • 2–15% after labor with prophylaxis
  • 5th leading cause of maternal mortality, accounting for 11% of maternal deaths

Risk Factors

• Cesarean delivery is the most important risk factor.
• Chorioamnionitis
• Bacterial vaginosis
• Group B streptococcal colonization of genital tract
• HIV infection
• Prolonged labor
• Prolonged rupture of membranes
• Multiple vaginal examinations
• Internal fetal monitoring during labor
• Operative vaginal delivery
• Manual extraction of the placenta
• Low socioeconomic status
• Obesity
• Anemia

General Prevention

• Vaginal delivery:
  • Avoid unnecessary vaginal examinations.
  • Treat chorioamnionitis during labor.
  • Spontaneous placental extraction
  • Avoid retained placental fragments or membranes.
  • Antibiotic prophylaxis for 3rd- and 4th-degree laceration (1)[B]
  • Use of aseptic technique during operative vaginal delivery.
  • No data to support antibiotic prophylaxis for operative vaginal delivery (2)[A]

• Cesarean delivery:
  • Preoperative preparation with a 10% povidone-iodine scrub and topical solution has been shown to decrease puerperal infection by 38% (3)[B].
  • Administering prophylactic antibiotics before both emergency and scheduled cesarean reduces the prevalence of postpartum infection after cesarean (4)[A]:
    • Administering the antibiotics prior to skin incision in cesarean delivery (as opposed to the prior practice of waiting for cord clamping) is considered the standard of care.
    • Antibiotics should be administered within 1 hour of the surgery start time.
    • There is a 40% reduction in postpartum maternal infections without any increase in neonatal infectious outcomes or difficulty in evaluating the neonate (5)[B].
  • Extending the spectrum of coverage to include both a cephalosporin and azithromycin decreases the incidence of infections (6)[A],(7)[B].
  • Vaginal preparation with povidone-iodine solution immediately before cesarean delivery reduces the risk of postoperative endometritis (8)[A].
  • Antibiotic dosage should be increased in obese patients to ensure appropriate tissue concentrations prior to skin incision (9)[B].

Etiology

• Endometritis commonly follows chorioamnionitis.
• Other infections follow trauma to the perineum, vagina, cervix, and uterus.
• Infection is nearly always polymicrobial and involves organisms that have ascended from the lower genital tract:
  • Aerobic isolates in 70%: Streptococcus faecalis, S. agalactiae, S. viridans, Staphylococcus aureus, Escherichia coli
  • Anaerobic isolates in 80%: Peptococcus sp., Peptostreptococcus sp., Clostridium sp., Bacteroides bivius, B. fragilis, Fusobacterium sp.
• Other genital mycoplasmata: Very common
• Herpes simplex virus and cytomegalovirus should be considered in immunocompromised patients if antibiotics fail.

Commonly Associated Conditions

• Chorioamnionitis
• Wound infection