Practice Essentials
Endometritis is inflammation of the endometrial lining of the uterus. In addition to the endometrium, inflammation may involve the myometrium and, occasionally, the parametrium.
Endometritis can be divided into pregnancy-related endometritis and endometritis unrelated to pregnancy. When the condition is unrelated to pregnancy, it is referred to as pelvic inflammatory disease (PID). Endometritis is often associated with inflammation of the fallopian tubes (salpingitis), ovaries (oophoritis), and pelvic peritoneum (pelvic peritonitis). The Centers for Disease Control and Prevention (CDC) guideline on treatment of sexually transmitted infections defines PID as any combination of endometritis, salpingitis, tubo-ovarian abscess, and pelvic peritonitis. [1]
The diagnosis of endometritis is usually based on clinical findings, such as fever and lower abdominal pain (see Presentation).
Most cases of endometritis, including those following cesarean delivery, should be treated in an inpatient setting. For mild cases following vaginal delivery, oral antibiotics in an outpatient setting may be adequate (see Treatment, as well as Medication).
Pathophysiology
Infection of the endometrium, or decidua, usually results from an ascending infection from the lower genital tract. From a pathologic perspective, endometritis can be classified as acute versus chronic. Acute endometritis is characterized by the presence of neutrophils within the endometrial glands. Chronic endometritis is characterized by the presence of plasma cells and lymphocytes within the endometrial stroma.
In the nonobstetric population, pelvic inflammatory disease and invasive gynecologic procedures are the most common precursors to acute endometritis. In the obstetric population, postpartum infection is the most common predecessor.
Chronic endometritis in the obstetric population is usually associated with retained products of conception after delivery or elective abortion. In the nonobstetric population, chronic endometritis has been seen with infections (eg, chlamydia, tuberculosis, bacterial vaginosis) and the presence of an intrauterine device.
The intrauterine device as a factor in the etiology of pelvic inflammatory disease was associated with early forms of the device, in particular, the Dalkon Shield. The incidence of pelvic inflammatory disease is not higher in users of modern intrauterine devices than in non-users. [2, 3, 4]
Etiology
Endometritis is a polymicrobial disease involving, on average, 2-3 organisms. In most cases, it arises from an ascending infection from organisms found in the normal indigenous vaginal flora.
Commonly isolated organisms include Ureaplasma urealyticum, Peptostreptococcus, Gardnerella vaginalis, Bacteroides bivius, and group B Streptococcus. Chlamydia has been associated with late-onset postpartum endometritis. Enterococcus is identified in up to 25% of women who have received cephalosporin prophylaxis.
Herpes and tuberculosis are rare causes, although in some countries tuberculosis is not an uncommon etiologic agent. [5, 6, 7]
Risk factors
Women are particularly vulnerable to endometritis after birth or abortion. In both the postpartum and postabortal state, risk is increased because of the open cervical os, presence of large amounts of blood and debris, and uterine instrumentation.
Major risk factors for obstetric endometritis include the following:
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Cesarean delivery (especially if before 28 weeks' gestation)
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Prolonged rupture of membranes
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Long labor with multiple vaginal examinations
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Severely meconium-stained amniotic fluid
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Manual placental removal [8]
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Extremes of patient age
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Low socioeconomic status
A study by Tuuli et al indicated that the risk of endometritis is significantly higher in cesarean deliveries performed during the second stage of labor (10 cm cervical dilation) than in those performed during the first stage (less than 10 cm dilation). Comparing 400 second-stage deliveries with 2105 first-stage procedures, the investigators found endometritis rates of 4.25% and 1.52%, respectively. A study by Asicioglu et al also found a higher endometritis rate, along with greater risk of other complications, in second-stage cesarean deliveries. [9, 10]
Minor risk factors include the following:
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Absence of the normal cervical mucus plug
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Administration of multiple courses of corticosteroids for prevention of premature delivery
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Prolonged internal fetal monitoring
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Prolonged surgery
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Postpartum anemia
The following factors increase the risk for endometritis in general:
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Presence of an intrauterine device: the vaginal part of the device may serve as a track for the organisms to ascend into the uterus
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Presence of menstrual fluid in the uterus
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Associated cervicitis secondary to gonorrhea or Chlamydia infection
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Frequent douching
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Unprotected sexual activity
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Multiple sexual partners
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Cervical ectopy
Epidemiology
The incidence of postpartum endometritis in the United States varies depending on the route of delivery and the patient population. After a vaginal delivery, incidence is 1-3%. Following cesarean delivery, the incidence ranges from 13-90%, depending on the risk factors present and whether perioperative antibiotic prophylaxis had been given. In the nonobstetric population, concomitant endometritis may occur in up to 70-90% of documented cases of salpingitis.
Prognosis
Nearly 90% of women treated with an approved regimen note improvement in 48-72 hours. Delay in initiation of antibiotic therapy can result in systemic toxicity.
Endometritis is associated with increased maternal mortality due to septic shock. However, mortality is rare in the United States because of aggressive antimicrobial management.
In the PID Evaluation and Clinical Health (PEACH) study, endometritis was not found to be associated with subsequent pregnancy-related complications, chronic pelvic pain, or infertility. [13]
Possible complications
Potential complications of endometritis include the following:
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Adnexal infection
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Parametrial phlegmon
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Pelvic abscess
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Pelvic hematoma
Spread of infection from the endometrium to the fallopian tubes, ovaries, or the peritoneal cavity may result in salpingitis, oophoritis, localized peritonitis, or tubo-ovarian abscesses. Salpingitis subsequently leads to tubal dysmotility and adhesions that result in infertility, higher incidence of ectopic pregnancy, and chronic pelvic pain.
