Identification of haptoglobin switch-on status in archived placental specimens indicates antenatal exposure to inflammation and potential participation of the fetus in triggering preterm birth

Fetal Hp switch-on status, a marker of antenatal exposure to intra-amniotic infection/inflammation, can be reliably established through evaluation of archived placental specimens. In the setting of infection/inflammation, Hp enhances placental PGE2 output thereby supporting the role of the fetus in triggering parturition.