eMedicine Specialties > Emergency Medicine > Obstetrics & Gynecology

Pregnancy, Postpartum Infections

Author: Andy W Wong, MD, Resident Physician, Department of Emergency Medicine, Wayne State University, Detroit Receiving Hospital
Coauthor(s): Adam J Rosh, MD, MS, Assistant Professor, Department of Emergency Medicine, Wayne State University/Detroit Receiving Hospital
Contributor Information and Disclosures

Updated: Aug 10, 2009

Introduction

Background

Postpartum infections comprise a wide range of entities that can occur after vaginal and cesarean delivery or during breastfeeding. In addition to trauma sustained during the birth process or cesarean procedure, physiologic changes during pregnancy contribute to the development of postpartum infections.¹ The typical pain that many women feel in the immediate postpartum period also makes it difficult to discern postpartum infection from postpartum pain.

Postpartum patients are frequently discharged within a couple days following delivery. The short period of observation may not afford enough time to exclude evidence of infection prior to discharge from the hospital. In one study, 94% of postpartum infection cases were diagnosed after discharge from the hospital.² Postpartum fever is defined as a temperature greater than 38.0°C on any 2 of the first 10 days following delivery exclusive of the first 24 hours.³ The presence of postpartum fever is generally accepted among clinicians as a sign of infection that must be determined and managed.

Pathophysiology

Local spread of colonized bacteria is the most common etiology for postpartum infection following vaginal delivery. Endometritis is the most common infection in the postpartum period. Other  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. Wound infection is more common with cesarean delivery.

Frequency

United States

Overall US rates for incidence and prevalence of postpartum infections is lacking. In a study by Yokoe et al in 2001, 5.5% of vaginal deliveries and 7.4% of cesarean deliveries resulted in a postpartum infection.² The overall postpartum infection rate was 6.0%. Endometritis accounted for nearly half of the infections in patients following cesarean delivery (3.4% of cesarean deliveries). Mastitis and urinary tract infections together accounted for 5% of vaginal deliveries.²

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.

A pregnancy-related mortality surveillance by the Centers for Disease Control and Prevention indicated infection accounted for about 11.6% of all deaths following pregnancy that resulted in a live birth, stillbirth, or ectopic.⁴

Race

The risk of postpartum urinary tract infection is increased in the African American, Native American, and Hispanic populations.⁵

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.
• Determine if the patient had any prenatal care.
• Determine if the patient was diagnosed or treated for any infections during pregnancy or during the antepartum period.
• 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 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 urinary tract infections (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
  • Route of delivery is the single most important factor in the development of endometritis.⁶
  • The risk of endometritis increases dramatically after cesarean delivery.^6,7
  • However, there is some evidence that hospital readmission for management of postpartum endometritis occurs more often in those who delivered vaginally.⁷
  • Other risk factors include prolonged rupture of membranes, prolonged use of internal fetal monitoring, anemia, and lower socioeconomic status.⁶
  • Perioperative antibiotics have greatly decreased the incidence of endometritis.⁶
  • In most cases of endometritis, the bacteria responsible 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.
• Wound 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.
  • Those who underwent cesarean delivery have a higher readmission rate for wound infection and complications than those who delivered vaginally.⁸
• Genital tract infections
  • Increased risk related to the duration of labor (ie prolonged labor increases risk of infection), use of internal monitoring devices, and number of vaginal examinations.⁹
  • 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.
• 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.
• General 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 including bacterial vaginosis
  • Diabetes
  • Nutritional status
  • Obesity

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