Listeriosis in pregnancy

M.G., a 24-year-old, healthy, gravida 2, para 1001 had an uncomplicated prenatal course, with a normal first trimester ultrasound and normal values on all routine prenatal labs. At 18 weeks' gestation, she presented to her midwife on labor and delivery complaining of severe abdominal pain and a sudden onset of fever. She was found to be febrile with a temperature of 38.5 degrees C and tachycardic with a pulse of 120 bpm. Using Doppler ultrasound, her nurse identified fetal heart tones. Her midwife noted fetal membranes bulging into the vagina through a dilated cervix on speculum exam. M.G. received fentanyl 100 mcg intravenously for pain. The midwife paged her consulting physician who arrived within 30 minutes. Shortly thereafter, M.G. gave birth to a normally formed fetus appropriate for 18 weeks gestation. The placenta delivered within a few minutes and was sent to the pathology department for culture. The placenta was noted to have a fibrous, exudative coating. M.G. received routine postpartum care and follow-up for a second-trimester abortion, including grief counseling. Her febrile illness resolved spontaneously within a day following the birth. The pathology report stated that the placenta had signs of chorioamnionitis and the culture grew Listeria monocytogenes. During postpartum follow-up, M.G. denied exposure to any of the foods known to be at high risk for L monocytogenes contamination.