Brown spotting or bleeding
can be a sign of pregnancy in certain situations. When an embryo implants into the uterus, there is often a small amount of bleeding for one day. Spotting after intercourse can happen later in pregnancy because of blood vessels that become more vulnerable on the cervix itself. Cervical blood vessels can break during sex, and cause some spotting. This is usually nothing to worry
I will say that the fact that you missed a period is much more of a sign that you could be pregnant than the spotting itself. Anytime you have had unprotected intercourse and your cycle is late, you should consider the possibility that you could be pregnant. I recommend that you schedule an appointment with your OBGYN. He or she can perform the pregnancy test and also perform a pelvic exam to determine if there is any other cause of your spotting. If you are pregnant, then you can begin routine prenatal care. Good luck.