Circadian Variation in the Onset of Placental Abruption

Figure 2

Circadian pattern of severe perinatal mortality. A case having IUFD, ND, low umbilical artery pH (UA pH < 7), or a low Apgar score at 5 minutes (<7) was regarded as having a severe perinatal outcome. Dark bar shows IUFD or ND. Striped bar represents low UA pH or a low Apgar score. White bar corresponds to the absence of severe perinatal mortality. Comparisons of the incidence of severe perinatal mortality among groups for the four 6-hour intervals in regard to placental abruption were made using tests followed by the Steel-Dwass test for multiple comparisons. A higher occurrence from 0:00 AM to 6:00 AM was detected when compared with 0:00 PM to 6:00 PM (). IUFD: intrauterine fetal death. ND: neonatal death.