This article is aimed at providing readers with a better understanding of several high risk pulmonary infections in pregnancy. These high-risk conditions are bacterial community-aquired pnewumonia (CAP), influenza, and varicella.

Community Acquired Pneumonia

Incidence: The incidence of CAP [community acquired pneumonia] appears to be comparable to that in non-pregnant patients. However, if acquired, it can result in greater morbidity and mortality because of the physiologic adaptations of pregnancy. It is a leading cause of fatal non-obstetric infection in the pregnant patient. Pneumonia has been reported in 4.2% of antepartum admissions for non-obstetric illnesses.

Maternal Risks: The major factor predisposing pregnant women to severe pneumonic infections is an alteration in immune status. These changes occur primarily in cell-mediated immunity, making viral, fungal, and tuberculous infections particularly pathogenic in these women. As pregnancy progresses, functional residual capacity is decreased by 10% to 25%; which impairs maternal ability to tolerate respiratory disease. A history of asthma, or anemia with hemoglobin less than 10 gm/dl has been shown to increase the incidence of pneumonia significantly. Mortality (compared to that for nonpregnant patients) is higher for viral pneumonia but not as clearly shown for CAP. There may be a higher risk of progression to ARDS and sepsis. However, because of potential higher risk, CAP patients do require aggressive management.

Fetal Disease Course: Pneumonia can cause significant stress to the fetus. Preterm delivery and lower birth weight are risks. Maternal bacteremia can lead to fetal sepsis in some cases.

Clinical Picture: Pneumonia may be misdiagnosed up to 20% of the time due to the many physiologic and anatomic changes of pregnancy. Up to 76% of pregnant patients have underlying subjective dyspnea at 31 weeks. Lung auscultation can be unreliable due to atelectasis of pregnancy. Many patients attribute symptoms of pneumonia to pregnancy.

Diagnostic testing: Diagnostic testing are similar to non-pregnant patients as are listed in the IDSA CAP guidelines. Imaging includes chest X-ray with abdominal shielding as study allows.

Treatment: Prompt diagnosis and treatment with current antimicrobial therapy and intensive care unit management of respiratory compromise has reduced the maternal morbidity and mortality due to pneumonia in pregnancy. Prevention with vaccination in at-risk populations may reduce the prevalence and severity of pneumonia in pregnant women.

Bacterial Pneumonia: Antibiotics are comparable to those used in non-pregnant population as recommended in resources such as Infectious Diseases Society of America/American Thoracic Society Consensus Guidelines on the management of community-acquired pneumonia in adults. This resource recommends fluoroquinolones such as moxifloxacin and gemifloxacin to be used in settings with high beta-lactam and macrolide resistance. The risk of teratogenicity is low, and fluoroquinolones can be given during pregnancy if indicated. Modifications in drug choice may be affected by changing local infection patterns.