Infection in Pregnancy

Bacteria of the Female Genital Tract

• Upper tract – sterile unless infected by ascending bacteria or hematogenous spread
• Lower tract – colonized with a mixture of commensal and pathogenic flora, which are similar to skin and fecal flora
• Lactobacilli species predominate Þ produce and thrive in acid environment (pH 3.8-4.2)
• changes in bacterial environment can affect pregnancy; Bacterial vaginalis (BV) Þ associated with preterm delivery

Antibiotics Contraindicated During Pregnancy

• Chloramphenicol – Grey Baby Syndrome; Tetracyclines – bone effects, dental stains; Quinolones – animal arthropathy/stunting; Sulfonamides – risk of neonatal jaundice (unsafe at term, but safe otherwise); Nitrofurantoin – G6PD deficient anemia; Aminoglycosides – otoxtocity Þ used in neonates for gram negative bacteria; no alternatives

Infections During Pregnancy

• Most infections are no more severe during pregnancy than in the absence of pregnany; none are less severe
• some are more severe (reason unknown): polio, influenza, varicella, amebioasis, listeria, malaria, coccidiomycosis
• Maternal Changes – minimal changes in immunoglobulins; no clear immune dysfunction
• Ý risk of upper respiratory tract infections(URI) and urinary tract infections(UTI), tendency toward earlier systemic invasion, and Ý risk for sepsis and life-threatening pulmonary fluid shift and adult respiratory distress syndrome (ARDS)
• Ý risk of URI: possibly due to ß plasma oncotic pressure, Ý O₂ demands, ß difference in alveolar closing pressures
• Ý risk of enteric infections: possibly due to altered gastric acidity and motility
• Teratogenic Infections–acronym "TORCH" Þ Toxoplasmosis, Other (Syphilis), Rubella Cytomegalovirus, and Herpes virus
• also trypanosomiasis, coxsackie virus, common colds, varicella, parvovirus B19, Venezuelan Equine Encephalitis (VEE)
• Toxoplasmosis – protozoan with tachyzoite, tissue cyst and oocyst phases: oocyst is infectious form
• acquired from undercooked meat and aerosolized cat feces Þ "Kitty Litter Disease"
• Maternal Symptoms – often asymptomatic; adenopathy malaise; only primary infection is dangerous to fetus unless immunosuppression causes recurrent attacks Þ fetal lesions and life-threatening maternal disease
• Neonatal Symptoms – CNS calcification, hydrocephaly, hepatic/splenic lesions, retinitis
• Diagnosis – history and serologic investigations, Ig assays and PCR of amniotic fluid and fetal blood
• Treatment – pyrimethamine/sulfadoxine or spiromycin; spiromycin does not cross the blood brain barrier
• Syphilis – STD caused by Treponema pallidum (9/100,000 women); can cause miscarriage
• Maternal Symptoms – same as non-pregnant pts.
• Neonatal Sympt.–bony lesions, jaundice, hepatosplenomegaly, mulberry molars, saber-shins, saddle nose, rhinorrhea
• Diagnosis – darkfield microscopy, serology of amniotic fluid and maternal or neonatal CSF
• Treatment–penicillin according to stage and HIV status (the only effective treatment–may have to desensitise if allergic)
• Rubella – virus, fetal exposure is dangerous through week 20; 50% affected if exposed during 1^st month, 10% after third
• Maternal Symptoms – minimal, rash, fever and mild adnopathy
• Neonatal Symptoms – cataracts, deafness, cardiac lesions, mental retardation, growth restriction
• Diagnosis – serologic testing
• Treatment – no effective treatment; vaccination program(RA 27/3 live virus); pregnancy interruption
• Cytomegalovirus – DNA herpesvirus; most prevalent cause for neonatal infections Þ 0.2 – 2 % of all live births; 10% result in clinical disease, 60% seroprevelance; spread by secretions, transfusion or vertically
• Maternal Symptoms – asymptomatic, mild mono-like illness with or without jaundice, primary infections most dangerous but reactivation accounts for almost ½ of infections; life threatening in immunosuppressed
• Neonatal Symptoms – hepatosplenomegaly, petechial skin lesions "blueberry muffin" chorioretinitis, hydrocephaly, hydrops, CNHS calcifications, growth restriction, deafness, neurobehavioral damage and death
• Diagnosis – serologic testing, antibody fixation testing, ultrasound PCR testing of amniotic fluid and fetal blood
• Treatment – no clearly effective treatments; future drugs Þ anti-retrovirals and hyperimmune gamma globulin

Sexually Transmitted Diseases – similar risk as other sexually active women

• Herpes Simplex Type 2–rarely teratogenic; vertical intrapartum transmission, primary infection in mother most dangerous
• Neonatal Symptoms – cataracts, microcephaly, growth restriction, encephalitis, pneumonia and skin lesions
• Treatment–cesarean if active lesions present; antiviral therapy for newborns and mothers; 25% of babies at risk infected
• Gonorrhea – dissemination more common if pregnant
• Congenial Symptoms – Neonatal opthalmitis can lead to blindness, sepsis, meningitis or death;
• Diagnosis – DNA probe and confirmatory culture
• Treatment – treat with 2^nd generation cephalosporins
• Chlamydia – late onset endometritis in mother and conjunctivitis and pneumonia in the newborn
• Diagnosis – DNA probe and confirmatory culture
• Treatment – Erythromycin; Tetracycline is contraindicated during pregnancy
• Human Papilloma Virus (HPV)–Ý lesion growth may be enhanced by estrogen, may obstruct canal and bleeding may be sufficient to require cesarean section; pediatric laryngeal papillomatosis may occur
• HIV – 4^th leading cause of death in women of childbearing age; maternal course is unaffected by pregnancy
• vertical transmission is 30% without maternal treatment; maternal antiviral therapy reduces vertical transmission
• Diagnosis – serologic testing, PCR for viral load
• Urinary Tract Infections
• more common in pregnancy because of hormonally mediated ureteral motility changes and mechanical obstruction
• usually caused by a single organism (gram negative enteric bacilli: E. coli, Klebsiella species, Group B Strep etc.)
• 2-7 % incidence of UTI; 25 progress to pyelonephritis if untreated
• Maternal Sympt.–can be asymptomatic, dysuria, frequent urination, fever, pain, urosepsis, associated with UTI and prematurity
• Treatment – oral antibiotics for lower tract infection; IV antibiotics for inpatients Þ emergency 

Pregnancy Specific Diseases

• Chorioamnionitis – 1-2% pregnancies; usu. polymicrobial, occasionally single strain (group B strep, gonococcus, listeria)
• Risk Factors – amniorrhexis, cerclage, labor duration, internal monitoring, exams, colonization by common pathogens
• Maternal Symptoms – fever, labor tachycardia, tenderness
• Neonatal Symptoms – cerebral palsy
• Diagnosis – WBC, CRP, amniocentesis and post facto placental culture and pathology
• Treatment – delivery and broad spectrum antibiotics
• Group B strep – gram positive bacterium with 10-20% colonization, frequent status change in women
• Maternal Symptoms – asymptomatic, urinary infections and endometritis
• Neonatal Symptoms – sepsis, pneumonia, late meningitis
• Diagnosis – culture with antenatal screening protocols; prophylactic treatment with intrapartum N penicillin
• Episiotomy Complications – uncommon; infections (0.05%), dehiscence (3-4%)
• polymicrobial pathogens with enteric anaerobes producing more sever cases
• Maternal Symptoms – fever, pain, purulence, incontinence, abscess
• Neonatal Effects – fistula formation, necrotizing fasciitis, sepsis
• Treatment – removal of sutures, debreedement, broad-spectrum antibiotics
• Peurperal Infections (Post Birth Infection) – polymicrobial, aerobes, rarely Group A streptococcus
• Symptoms – fever, uterine tenderness, foul lochia (discharge of tissue, blood and mucus following child birth)
• often self limiting; severe infections have sepsis, abscess, septic pelvic thrombophlebitis (SPT) and death
• Diagnosis – clinical, blood or cervical cultures
• Treatment - broad spectrum IV antibiotics; heparin for SPT