Circadian Variation in the Onset of Placental Abruption

Figure 1

Circadian pattern of onset of disease based on initial symptoms. Initial symptoms included abdominal pain (white), vaginal bleeding (striped), abdominal pain and bleeding (dark), or others (gray). Comparisons of incidence of symptom-oriented disease onset 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 level of abdominal pain from 0:00 AM to 6:00 AM was detected when compared with 0:00 PM to 6:00 PM ().