Bleeding during pregnancy: implantation vs ectopic
An ectopic pregnancy develops outside the uterine cavity. In the US this occur in 1 in 50 pregnancies. Although some ectopic pregnancies " miscarry" without complication, there is a risk that the pregnancy may continue to grow and rupture through the wall of the fallopian tube. The vast majority of ectopic pregnancies occur in the fallopian tubes, but occasionally they may be found on the ovary or in the abdominal cavity.
The general symptoms are the same as those of early pregnancy, accompanied by a positive pregnancy test and lower abdominal pain, which almost always starts before any vaginal bleeding has occurred.
Heavy vaginal bleeding is unlikely, unless the ectopic pregnancy occurs in the cervix.
If the fallopian tube ruptures, heavy bleeding inside the abdomen is likely — followed by lightheadedness, fainting and shock.
An ultrasound scan will show that there is no pregnancy sac within the uterine cavity, although the lining of the uterus may be thickened.
Implantation bleeding — typically defined as bleeding that occurs 10 to 14 days after conception — is normal and relatively common.
Implantation bleeding is thought to happen when the fertilized egg attaches to the lining of the uterus. Implantation bleeding usually occurs around the time you would expect to have a menstrual period. However, implantation bleeding generally lasts for a short time and is usually much lighter than menstrual bleeding.