Retained placenta and associated risk factors.

In a retrospective study, the factors that might influence the retention of placenta such as age, parity, antenatal abnormalities, labour onset and duration, history of uterine surgery and previous retained placenta, were studied in 146 patients with retained placenta. Three hundred women who were delivered vaginally without retained placenta were similarly evaluated under the same conditions. The results showed (in descending order of significance), history of retained placenta, previous uterine surgery, preterm delivery, age above 35 years, placental weight less than 601 g, pethidine use in labour, labour induction and parity of more than five to be associated with retained placenta. The existence of some or all these risk factors in a pregnant woman should alert the obstetrician about the possibility of retained placenta in labour.