Antepartum bleeding of unknown origin in the second half of pregnancy and pregnancy outcomes

Objective The purpose of our investigation was to evaluate factor(s) associated with unexplained antepartum bleeding of unknown origin (ABUO) after 24 weeks of pregnancy and correlate unexplained haemorrhage with maternal and perinatal outcomes. Design This is a retrospective observational study. Setting King Edward Memorial Hospital (KEMH), Subiaco, Western Australia. Population Singleton pregnancies delivering at KEMH between January 1998 and December 2004. Methods ABUO was defined as bleeding after 20 weeks of gestation but before the onset of labour with no cause detected on vaginal examination or abdominal ultrasound. Outcomes of these pregnancies were collated and compared with those of pregnancies without ABUO. Main outcome measures Antepartum complications assessed included pre-eclampsia/eclampsia, gestational diabetes and preterm birth. Intrapartum evaluations included labour inductions, mode of delivery and gestational age at delivery. Neonatal outcomes evaluated included birthweight, Apgar scores, newborn intensive care unit (NICU) admission, neonatal complications and risk of perinatal/neonatal death. Results Between January 1998 and December 2004, there were 26 583 deliveries without ABUO and 1431 with ABUO. Multivariable analyses of the ABUO effects revealed that ABUO was a simultaneously significant risk factor for term labour inductions (OR = 2.00, 95% CI: 1.72-2.32, P < 0.001), preterm delivery (OR = 4.31, 95% CI: 3.84-4.84, P < 0.001), NICU admission (OR = 1.23, 95% CI: 1.01-1.51, P = 0.042), hyperbilirubinaemia (OR = 1.29, 95% CI: 1.01-1.63, P = 0.041) and reduced birthweight (26 g, 95% CI: 3-50, P = 0.026). Conclusion Women with ABUO are at greater risk of preterm delivery, term labour induction and their neonates are at greater risk for NICU admissions, hyperbilirubinaemia and a reduced birthweight.