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

o Lactobacilli species predominate  produce and thrive in acid environment (pH 3.8-4.2)

o changes in bacterial environment can affect pregnancy; Bacterial

vaginalis (BV)  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  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

o some are more severe (reason unknown): polio, influenza, varicella, amebioasis, listeria,
malaria, coccidiomycosis

 Maternal Changes – minimal changes in immunoglobulins; no clear immune dysfunction

o  risk of upper respiratory tract infections(URI) and urinary tract infections(UTI), tendency
toward earlier systemic invasion, and  risk for sepsis and life-threatening pulmonary fluid
shift and adult respiratory distress syndrome (ARDS)

o  risk of URI: possibly due to  plasma oncotic pressure,  O2 demands,  difference in

alveolar closing pressures

o  risk of enteric infections: possibly due to altered gastric acidity and motility

 Teratogenic Infections–acronym "TORCH"  Toxoplasmosis, Other

(Syphilis), Rubella Cytomegalovirus, and Herpes virus

o 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

o acquired from undercooked meat and aerosolized cat feces  "Kitty Litter Disease"

o Maternal Symptoms – often asymptomatic; adenopathy malaise; only primary infection is

dangerous to fetus unless immunosuppression causes recurrent attacks  fetal lesions
and life-threatening maternal disease

o Neonatal Symptoms – CNS calcification, hydrocephaly, hepatic/splenic lesions, retinitis

o Diagnosis – history and serologic investigations, Ig assays and PCR of amniotic fluid and
fetal blood

o 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

o Maternal Symptoms – same as non-pregnant pts.

o Neonatal Sympt.–bony lesions, jaundice, hepatosplenomegaly, mulberry molars, saber-

shins, saddle nose, rhinorrhea

o Diagnosis – darkfield microscopy, serology of amniotic fluid and maternal or neonatal

CSF

o 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
1st month, 10% after third

o Maternal Symptoms – minimal, rash, fever and mild adnopathy

o Neonatal Symptoms – cataracts, deafness, cardiac lesions, mental retardation, growth

restriction

o Diagnosis – serologic testing

o Treatment – no effective treatment; vaccination program(RA 27/3 live virus); pregnancy

interruption

 Cytomegalovirus – DNA herpesvirus; most prevalent cause for neonatal infections  0.2 – 2 %
of all live births; 10% result in clinical disease, 60% seroprevelance; spread by secretions,
transfusion or vertically

o 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
 o Neonatal Symptoms – hepatosplenomegaly, petechial skin lesions "blueberry muffin"
chorioretinitis, hydrocephaly, hydrops, CNHS calcifications, growth restriction, deafness,
neurobehavioral damage and death

o Diagnosis – serologic testing, antibody fixation testing, ultrasound PCR testing of

amniotic fluid and fetal blood

o Treatment – no clearly effective treatments; future drugs  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

o Neonatal Symptoms – cataracts, microcephaly, growth restriction, encephalitis,

pneumonia and skin lesions

o Treatment–cesarean if active lesions present; antiviral therapy for newborns and

mothers; 25% of babies at risk infected

 Gonorrhea – dissemination more common if pregnant

o Congenial Symptoms – Neonatal opthalmitis can lead to blindness, sepsis, meningitis or

death;

o Diagnosis – DNA probe and confirmatory culture

o Treatment – treat with 2nd generation cephalosporins

 Chlamydia – late onset endometritis in mother and conjunctivitis and pneumonia in the newborn

o Diagnosis – DNA probe and confirmatory culture

o Treatment – Erythromycin; Tetracycline is contraindicated during pregnancy

 Human Papilloma Virus (HPV)– 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 – 4th leading cause of death in women of childbearing age; maternal course is unaffected by
pregnancy

o vertical transmission is 30% without maternal treatment; maternal antiviral therapy

reduces vertical transmission

o Diagnosis – serologic testing, PCR for viral load

 Urinary Tract Infections

 o more common in pregnancy because of hormonally mediated ureteral motility changes
and mechanical obstruction

o usually caused by a single organism (gram negative enteric bacilli: E. coli, Klebsiella
species, Group B Strep etc.)

o 2-7 % incidence of UTI; 25 progress to pyelonephritis if untreated

o Maternal Sympt.–can be asymptomatic, dysuria, frequent urination, fever, pain,

urosepsis, associated with UTI and prematurity

o Treatment – oral antibiotics for lower tract infection; IV antibiotics for

inpatients  emergency

Pregnancy Specific Diseases

 Chorioamnionitis – 1-2% pregnancies; usu. polymicrobial, occasionally single strain (group B
strep, gonococcus, listeria)

o Risk Factors – amniorrhexis, cerclage, labor duration, internal monitoring, exams,

colonization by common pathogens

o Maternal Symptoms – fever, labor tachycardia, tenderness

o Neonatal Symptoms – cerebral palsy

o Diagnosis – WBC, CRP, amniocentesis and post facto placental culture and pathology

o Treatment – delivery and broad spectrum antibiotics

 Group B strep – gram positive bacterium with 10-20% colonization, frequent status change in
women

o Maternal Symptoms – asymptomatic, urinary infections and endometritis

o Neonatal Symptoms – sepsis, pneumonia, late meningitis

o Diagnosis – culture with antenatal screening protocols; prophylactic treatment with

intrapartum N penicillin

 Episiotomy Complications – uncommon; infections (0.05%), dehiscence (3-4%)

o polymicrobial pathogens with enteric anaerobes producing more sever cases

o Maternal Symptoms – fever, pain, purulence, incontinence, abscess

o Neonatal Effects – fistula formation, necrotizing fasciitis, sepsis

o Treatment – removal of sutures, debreedement, broad-spectrum antibiotics

 Peurperal Infections (Post Birth Infection) – polymicrobial, aerobes, rarely Group A
streptococcus

o 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

o Diagnosis – clinical, blood or cervical cultures

o Treatment - broad spectrum IV antibiotics; heparin for SPT