Home Economics American Trypanosomiasis Chagas Disease, Second Edition: One Hundred Years of Research
Timing of maternal—fetal transmission of Trypanosoma cruzi
There is likely little or no transmission of blood trypomastigotes during the first trimester of pregnancy, since the placental intervillous space is not open. Maternal blood supply becomes continuous and diffuse in the entire placenta only after the 12th week of gestation.59 The absence of developmental malformations in live
newborns congenitally infected with T. cruzi (see section: Clinical manifestations of congenital Chagas disease) also suggests there is no transmission at the early stages of organogenesis in the embryo.
Abortions, stillbirths, and premature births in T. cruzi-infected women are more frequent for gestational ages between 19 and 37 weeks of pregnancy, but the proof of congenital infection as responsible for such pejorative outcomes has not been systematically investigated.51,60 The rare reported cases of acute T. cruzi infection during pregnancy indicate possible transmission around the 20th week of pregnancy.61 However, in most pregnant women who are in the chronic phase of infection (see section: Epidemiological features specific to congenital infection with Trypanosoma cruzi), it is impossible to pinpoint the timing of maternal—fetal transmission of T. cruzi. Transmission rates in vaginal and cesarean deliveries of infected women are similar (see Ref. , unpublished own data), indicating that most transmissions are prenatal, though possible later additional perinatal transmission during labor cannot be excluded (see section: Interpretation attempt of Trypanosoma cruzi—placenta interactions).
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