Case Study

A multiparous woman at 37 weeks’ gestation was admitted to the delivery suite for induction of labor. She had ruptured her membranes 24 hours previously, but labor had not begun. She was induced with a syntocinon infusion and received an epidural for labor analgesia.

Two hours after the onset of labor, she developed a pyrexia and low-grade tachycardia. Her labor progressed uneventfully, and she delivered vaginally but suffered a postpartum hemorrhage of 1000 ml secondary to uterine atony.

The day after delivery, the patient complained of feeling tired and had abdominal pain but was keen to be discharged because she had another child at home.

The community midwife reviewed her the day after discharge (day 2 postpartum). She was noted to have a tachycardia of 110 beats/min, a temperature of 37.9°C (100.2°F), and her abdominal pain had worsened. She was advised to return to the maternity unit immediately.

On admission to the labor ward, clinical examination noted that in addition to the tachycardia and pyrexia, the patient was also tachypnea, with a respiratory rate of 22 breaths/min. The medical team assessed her urgently. A diagnosis of sepsis was made, and an abdominal ultrasound scan confirmed the presence of retained products of conception in her uterus. IV antibiotics and fluid resuscitation were started immediately. She underwent surgical removal of the retained products of conception, and she made a full recovery.

Key Points

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  This patient had documented risk factors for sepsis (premature rupture of membranes, pyrexia in labor).

  
  
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  The diagnosis of sepsis was initially delayed.

  
  
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  When the diagnosis was made, prompt treatment including antibiotics and removal of the septic focus lead to a good outcome.

Discussion

Sepsis in obstetrics is an important cause of maternal mortality and morbidity worldwide and accounts for 11 percent of all maternal deaths.¹ The UK maternal mortality rate from sepsis almost tripled between 1980 and 2008.² In the United States, a retrospective analysis of almost 45 million hospitalizations for delivery between 1998 and 2008 demonstrated that sepsis complicated 1 per 3,333 deliveries, with severe sepsis complicating approximately 1 per 11,000 deliveries.³ Sepsis in obstetrics is associated with significant morbidity, including fetal demise, organ failure, chronic pelvic inflammatory disease, bilateral tubal occlusion, and infertility. Early recognition and timely response are keys to ensuring a good outcome.

Risk Factors

A number of risk factors are associated with an increased risk of developing sepsis in obstetrics (Table 47.1). These may be broadly divided into intrinsic patient factors and obstetric factors. Obese women are twice as likely to develop obstetric sepsis as normal weight women.⁴ Although relatively infrequent in pregnancy, chronic comorbid conditions such as congestive heart failure, chronic liver disease, and chronic renal disease are risk factors for sepsis in the general population, and these associations have been demonstrated in pregnancy as well.³ Women with systemic lupus erythematosus are also at risk of developing sepsis, likely as a result of the immunologic effects of the disease itself but also secondary to the use of steroids and immunosuppressive medications. Although women with these conditions are a relatively small proportion of obstetric patients, the magnitude of risk associated with these conditions prompts early consideration of the diagnosis and treatment of sepsis in patients with these conditions.

Causes of Sepsis in Obstetrics

The causes of sepsis in obstetrics may be divided into obstetric and other causes (Table 47.2). Sepsis can arise at any time during pregnancy, labor, and the postpartum period, and the cause may vary depending on the stage of pregnancy. In early pregnancy, the most common causes of sepsis are septic abortion and termination of pregnancy.

Surgical intervention, in particular cesarean delivery, is one of the most important risk factors for the development of sepsis in obstetrics. Women undergoing cesarean delivery have a 5- to 20-fold greater risk for infection and infectious morbidity compared with a vaginal birth.⁵ It has been shown that the risk of postpartum infection within 30 days of delivery for women delivered by cesarean delivery (elective and emergency) was 7.6 percent versus 1.6 percent for women who had a vaginal delivery.⁶ Following emergency cesarean delivery, there is a nearly 50 percent higher risk of postpartum wound infection compared with elective cesarean delivery. The use of prophylactic antibiotics before surgical incision is therefore recommended.^{7, 8} A Cochrane review found that prophylactic antibiotics in women undergoing cesarean delivery substantially reduced the incidence of febrile morbidity, wound infection, endometritis, and serious maternal infectious complications.⁵ However, even with prophylactic antibiotics, infection remains a significant risk in women who deliver by cesarean delivery.

Pregnant women are more vulnerable to urinary tract infection, which can lead to sepsis. In pregnancy, there is decreased peristalsis of the ureters, increased bladder capacity, and urinary stasis caused by progesterone-induced smooth muscle relaxation. In addition, as a result of the mechanical effects of the gravid uterus, there may be renal pelvic and ureteric dilatation.^{9, 10}

Mastitis affects up to 20 percent of postpartum women but is comparatively rare as a cause of postpartum sepsis. It has been estimated that up to a third of women admitted with mastitis develop breast abscess that requires surgical drainage.¹¹

Pneumonia is one of the leading causes of sepsis arising in the antepartum period and is associated with significant morbidity and mortality. In the United Kingdom, it is the most common reason for admission to intensive care for pregnant women.¹² Comorbidities in pregnancy including asthma, cardiac disease and obesity increase the risk of developing pneumonia. In pregnant women who develop pneumonia, there is a higher rate of maternal and fetal complications such as respiratory failure and pneumothorax, intrauterine growth retardation and in utero death; preterm delivery may be required to improve maternal respiratory function.^{13, 14}

The specific physiologic respiratory changes of pregnancy predispose the parturient with pneumonia to rapid desaturation and a reduced ability to compensate for the development of a metabolic acidosis. The differential diagnosis of pneumonia in pregnancy includes pulmonary embolus and pulmonary edema. Pregnancy does not exclude the use of chest radiography, which can assist with diagnosis. The consequences of viral pneumonia in pregnancy have been particularly topical in recent years as a result of the H1N1 flu pandemic. Women in pregnancy and the post-partum period are known to be at higher risk of complications of seasonal flu than the non-pregnant population. In previous flu pandemics, pregnant women had significantly higher mortality and morbidity rates, and this effect was seen in the 2009 pandemic.¹⁵ Although the use of neuraminidase inhibitors has not been demonstrated to be beneficial in the nonobstetric population, there is good observational evidence that pregnant women may benefit from these drugs. A pregnant woman in whom influenza is suspected should be started on these drugs without delay, and pregnant women should be encouraged to receive seasonal influenza vaccination.¹⁶

Microbiology

The genitourinary tract is colonized with a wide variety of organisms, but not all of these will cause infection and sepsis. One of the most important organisms associated with obstetric sepsis in recent years has been Group A streptococcus. It has been estimated that in the developed world, between 5–30 percent of the community are asymptomatic carriers of Group A streptococci, usually on the skin or in the throat. In the UK Confidential Maternal Death Enquries of 2006–8, several of the women who died had a history of a recent upper respiratory tract infection and/or contact with young children.² It is thought that following contact with Group A streptococcus, these women autoinoculate themselves through contamination of the perineum, and the organism then ascends leading to systemic infection. The presence of upper respiratory tract symptoms should alert the clinician to the possibility of Group A streptococcus or influenza as a possible diagnosis. If a woman has a sore throat, the Centor criteria are useful to predict bacterial infection.¹⁷ The presence of three or four of the following signs suggests that a woman may have a bacterial infection and would benefit from antibiotics:

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  Tonsillar exudate

  
  
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  Tender anterior cervical lymphadenopathy or lymphadenitis

  
  
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  Fever

  
  
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  An absence of cough

Other important microorganisms include Escherichia coli, Meningococcus, Staphylococcus, Streptococcus pneumonia, and Pseudomonas. Of particular concern is sepsis arising as a result of Extended-Spectrum-Beta-Lactamase-producing organisms.¹⁸ Extended-Spectrum-Beta-Lactamases (ESBLs) are enzymes that can be produced by bacteria that make them resistant to third-generation cephalosporins commonly used for the treatment of serious infections. ESBL-producing organisms occur principally in Enterobacter species, E. coli, Klebsiella pneumoniae, and Proteus mirabilis (all recognized causes of obstetric sepsis).

One of the most important factors in obstetric sepsis, particularly in the undeveloped world, is the HIV/AIDS pandemic.¹⁹ Pregnant women with HIV/AIDS are more susceptible to sepsis and postoperative complications. Many opportunistic infections associated with HIV/AIDS may complicate pregnancy and cause maternal mortality. Pregnant women with HIV/AIDS are more susceptible to infection, and in addition, infections such as Pneumocystis jirovecii (previously carinii) pneumonia have a more aggressive course during pregnancy, with an increase in both morbidity and mortality. The most significant infection contributing to maternal mortality in HIV-infected women is tuberculosis (which is the most common opportunistic infection associated with HIV in the undeveloped world). It has been estimated that maternal mortality in HIV-infected women is 6.2 times greater than in HIV-negative women.