Pregnancy, Postpartum Infections

Emergency physicians are increasingly concerned about postpartum patients who come to the ED with a fever or evidence of infection. The number of cases of infection can be expected to increase because of the earlier discharge of postpartum patients from the hospital. Any infection following delivery is classified as postpartum or puerperal infection.

Pathophysiology

Endometritis is the most common source of postpartum infection. Other sources of postpartum infections include (1) postsurgical wound infections, (2) perineal cellulitis, (3) mastitis, (4) respiratory complications from anesthesia, (5) retained products of conception, (6) urinary tract infections (UTIs), and (7) septic pelvic phlebitis.

Frequency

United States

Overall, postpartum infection is estimated to occur in 1-8% of all deliveries.

Mortality/Morbidity

In most reviews, maternal death rates associated with infection range from 4-8%, or approximately 0.6 maternal deaths per 100,000 live births.

Clinical

History

The history and course of the delivery is important in the evaluation of postpartum patients.

• Ascertain if the delivery was vaginal or cesarean.
• Ascertain if premature rupture of the membranes occurred.
• Assess the patient's symptoms.
• Features vary depending on the source of infection and may include the following:
  • Flank pain, dysuria, and frequency of UTIs
  • Erythema and drainage from the surgical incision or episiotomy site, in cases of postsurgical wound infections
  • Respiratory symptoms, such as cough, pleuritic chest pain, or dyspnea, in cases of respiratory infection or septic pulmonary embolus
  • Fever and chills
  • Abdominal pain
  • Foul-smelling lochia
  • Breast engorgement in cases of mastitis

Physical

Focus the physical examination on identifying the source of fever and infection. A complete physical examination, including pelvic and breast examinations, is necessary. Findings may include the following:

• Endometritis may be characterized by lower abdominal tenderness on one or both sides of the abdomen, adnexal and/or parametrial tenderness elicited with bimanual examination, temperature elevation (most commonly >38.3°C)
• Some women have foul-smelling lochia without other evidence of infection. Some infections, most notably caused by group A beta-hemolytic streptococci, are frequently associated with scanty, odorless lochia.
• Patients with wound infections, or episiotomy infections, have erythema, edema, tenderness, and discharge from the wound or episiotomy site.
• Patients with mastitis have very tender, engorged, erythematous breasts. Infection frequently is unilateral.
• Patients with pyelonephritis or UTIs may have tenderness at the costovertebral angle and an elevated temperature.
• Respiratory signs, such as rales, consolidation, or rhonchi in pneumonia, are possible.
• Patients with septic pelvic thrombosis, although rare, may have palpable pelvic veins. These patients also have tachycardia that is out of proportion to the fever.

Causes

Causes and risk factors may include the following:

• Endometritis
  • In most cases of endometritis, the bacteria responsible for pelvic infections are those that normally reside in the bowel, vagina, perineum, and cervix.
  • The uterine cavity is usually sterile until the rupture of the amniotic sac. As a consequence of labor, delivery, and associated manipulations, anaerobic and aerobic bacteria can contaminate the uterus.
  • The risk of endometritis increases dramatically after cesarean delivery (10-20% of patients).
• Genital tract infections
  • Genital tract infections are generally polymicrobial.
  • Gram-positive cocci and Bacteroides and Clostridium species are the predominant anaerobic organisms involved. Escherichia coli and gram-positive cocci are commonly involved aerobes.
• Mastitis
  • The most common organism reported in mastitis is Staphylococcus aureus.
  • The organism usually comes from the breastfeeding infant's mouth or throat.
• Thrombosis
  • Numerous factors cause pregnant and postpartum women to be more susceptible to thrombosis. Pregnancy is known to induce a hypercoagulable state secondary to increased levels of clotting factors. Also, venous stasis occurs in the pelvic veins during pregnancy.
  • Although relatively rare, septic pelvic thrombosis is occasionally observed in the postpartum patient, who might have fever.
• Perineal cellulitis and episiotomy site infections
  • Most often, the etiologic organisms associated with perineal cellulitis and episiotomy site infections are Staphylococcus or Streptococcus species and gram-negative organisms, as in endometritis.
  • Vaginal secretions contain as many as 10 billion organisms per gram of fluid. Yet, infections develop in only 1% of patients who had vaginal tears or who underwent episiotomies.
• Urinary tract infections
  • Bacteria most frequently found in UTIs are normal bowel flora, including E coli and Klebsiella, Proteus, and Enterobacter species.
  • Any form of invasive manipulation of the urethra (eg, Foley catheterization) increases the likelihood of a UTI.
• Risk factors
  • History of cesarean delivery
  • Premature rupture of membranes
  • Frequent cervical examination (Sterile gloves should be used in examinations. Other than a history of cesarean delivery, this risk factor is most important in postpartum infection.)
  • Internal fetal monitoring
  • Preexisting pelvic infection
  • Diabetes
  • Nutritional status
  • Obesity