Causes of primary postpartum haemorrhage after vaginal delivery

Background: obstetrical hemorrhage is the commonest cause of maternal death in developing countries. traditionally it is defined as blood loss of more than 500 ml from genital tract after delivery of baby. the most common cause is uterine atony and rest of the causes includes retained product of conception (rpoc),genital tract trauma and coagulopathy. aim: to identify the cause of primary post-partum hemorrhage (pph) following vaginal deliveries. methods: this cross-sectional study was carried out at department of obstetrics & gynecology,unit iii,civil hospital karachi from 1st january 2008 to 30th june 2008. fifty patients were included,who went into pph within 24 hours after vaginal delivery in the hospital. the cause of each case was identified including uterine atony,retained product of conception,genital tract trauma and coagulopathy. results: sixty six percent of patients had uterine atony,thus found to be the commonest cause of primary pph followed by rpoc including retained placenta (18%). sixteen percent patients suffered genital tract trauma and none had coagulopathy. conclusion: uterine atony found to be most common cause of primary pph. for primary pph it should be considered as provisional diagnosis,until unless other cause is diagnosed as definite diagnosis.