Maternal infection resulting in sepsis may cause up to 30% of the ICU admissions occurring in obstetric patients and contribute to 2%-3% of maternal mortality in developed nations.1,2 Pregnancy renders women more susceptible to sepsis and to resulting severe complications. Also, microbiology of sepsis is distinct in pregnancy; endotoxin-producing Gram-negative rods such as E. coli are common etiologic agents, whereas Gram-positive bacteria are common culprits in nonpregnant patients with sepsis.3
Explore This IssueACEP News: Vol 31 – No 05 – May 2012
Most of sepsis-related research and literature is centered on nonpregnant patients; management of severe infections in pregnancy requires integration of clinical skills associated with management of sepsis and the unique pathophysiology that can occur in pregnancy. These cases may be best managed by experienced teams of physicians (including MFM, anesthesia, infectious disease, and ICU physicians) with supporting nursing and ancillary ICU staff.1,4,5,6
A list of infection sites and pathogens commonly seen in pregnancy is given in Table 1. Table 2 provides a clinical tool covering key principles.
Special Considerations in Pregnancy
Certain infections in pregnancy can be teratogenic to the fetus, particularly in the first trimester. These agents have been given the acronym of TORCH for toxoplasmosis, other (e.g., syphilis), rubella, cytomegalovirus, and herpesvirus. Although not teratogenic, HIV may be transmitted to the fetus and may be lethal in the child. Hence, the timely recognition and treatment of infections is important. Screening tests can be done by the admitting team.
Infection in pregnancy is associated with increased frequency and severity in certain anatomic sites because of anatomic and physiologic changes associated with pregnancy, delivery, and especially with tissue injury and bacterial contamination associated with cesarean delivery.
Physiologic Changes of Pregnancy
Certain normal physiologic changes in pregnancy may cause delay in diagnosis of sepsis and/or promote difficulties or complications when treating sepsis in pregnancy. For example:
- Normal pregnancy may be associated with a heart rate >90 bpm and hyperventilation with PaCO2 <32 mm Hg, and normal labor is often associated with a WBC count >12,000 cells/mcL (all signs of systemic inflammatory response syndrome [SIRS] in the nonpregnant patient).
- Renal system smooth-muscle relaxation in pregnancy increases the rate and severity of urinary tract infections while delaying recognition of symptoms until pyelonephritis occurs.
- Decreased plasma colloid osmotic pressure and an increased tendency for capillary leakage in pregnancy may contribute to pulmonary edema or adult respiratory distress syndrome when IV fluid bolus treatment is needed in treating septic shock.
- Pregnancy increases concentrations of coagulation factors and the vulnerability to disseminated intravascular coagulation as a complication of severe sepsis.
- Compression of the inferior vena cava by the gravid uterus associated with the supine position of the patient may cause hypotension or contribute to cardiovascular collapse previously initiated by septic shock.
- The gravid uterus acts as a large arteriovenous shunt that cannot respond effectively to hypotension, leaving pregnant patients more vulnerable to shock.
- Markers of standard sepsis treatment are altered. Central venous pressure can be increased to 10 mm Hg in the third trimester, the mean arterial blood pressure is decreased, and the ScvO2 can be as high as 80%.
The presence of the fetus may complicate the management of sepsis in pregnancy in several ways:
- The products of conception may be the source of infection (especially when rupture of membranes or chorioamnionitis is present), and the fetus may need to be delivered before maternal sepsis can be effectively treated. This may occur before or after potential fetal viability.
- The fetus is vulnerable to infection or the decreased perfusion of sepsis and may need to be delivered emergently to survive. Monitoring and intervening when needed for the sake of the fetus can complicate the management of sepsis in pregnancy significantly.
- Some of the physiologic changes of pregnancy that can promote maternal compromise associated with septic shock (such as inferior vena cava compression syndrome and the uterine A-V shunt effect) can be attenuated by delivery of the fetus.
A number of viral infections commonly complicate pregnancy and in some cases can have profound effects on the fetus. Initial presentation may suggest bacterial sepsis. Unless a clear viral etiology is present without secondary bacterial infection, the EP will generally initiate empirical sepsis treatment. Studies have revealed that viral infection of the placenta can sensitize the pregnant mother to bacterial products and induce preterm labor, in addition to eliciting a fetal inflammatory response that can cause end-organ damage.1,7