According to Women's Health, decidual bleeding during pregnancy is caused by the coming apart of elements of the uterine lining and is common in the early stages of pregnancy before the placenta and lining have joined. Between 20 and 30 percent of women will have some type of vaginal or uterine bleeding in the first trimester of pregnancy, and some women may continue to have decidual bleeding throughout their pregnancies.
While decidual bleeding may feel disturbing, it poses no threat to a mother or her baby most of the time. However, Mayo Clinic cautions that some causes of decidual bleeding are serious. For instance, the condition can indicate a potential miscarriage before the 20th week of pregnancy. Implantation bleeding that occurs up to two weeks after conception and cervical complications, such as infections, molar pregnancy and ectopic pregnancy, are also associated with decidual bleeding.
Since bleeding can sometimes be caused by a more serious condition, Women’s Health advises pregnant women who experience any type of bleeding to consult a doctor. According to the American Academy of Family Physicians, a family doctor who has a good grasp of the normal development of early pregnancy anatomy and sonographic results is in a good position to give an accurate diagnosis of decidual bleeding and offer appropriate treatment.