Subchorionic hemorrhage happens in about 1% of all pregnancies, but it is the cause of about 20% of all the bleeding in the first trimester. About a quarter of women will experience bleeding in the first trimester.
A subchorionic hemorrhage may cause bleeding that is visible. It can be varying in quantity from spotting in pregnancy to heavy bleeding. The blood can be pink in color to bright red or brown. Ultrasound is used to diagnose the bleeding.
Subchorionic Hemorrhage. Avneesh Chhabra, MD. eMedicine. Last accessed January 25, 2014