It is hypothesized that development of early subchorionic hemorrhage may lead to disruption in the placental-uterine matrix resulting in an adherence of the placenta to the endometrium. We sought to evaluate the effect of a first trimester bleed on the need for a post-vaginal delivery D&C for removal of retained placenta.METHODS:
We carried out a case-control study at a tertiary care centre in Montréal, Canada between 2012 and 2016. Women identified through medical records as having had a post vaginal delivery D&C for retained placenta were considered cases and matched 2:1 with women delivering vaginally the same day as the case who did not have a retained placenta requiring D&C. Logistic regression evaluated the adjusted effect of a first trimester bleed on the requirement for D&C for retained placenta.RESULTS:
There were 68 cases of retained placenta requiring D&C for an estimated 3/1,000 deliveries. Women requiring a D&C for placental removal were slightly older than controls but otherwise comparable in baseline characteristics. First trimester bleeding was more common among women requiring a D&C for retained placenta 11.8% vs 1.5%, respectively. In adjusted analysis, first trimester bleeding was strongly associated with requiring a D&C for removal of retained placenta (OR 7.70, CI 1.37.5). As well, it was associated with a greater postpartum hemorrhage and requirement for blood transfusions.CONCLUSION:
First trimester bleeding is associated with a greater risk of retained placenta requiring D&C and blood transfusions. Women with a first trimester bleed should be considered at increased risk of postpartum hemorrhage and retained placenta.