Hi, Thanks for the query. The commonest cause of bleeding in the first trimester is threatened abortion or incomplete abortion. In both cases the pregnancy test is usually positive. Threatened abortion is a condition when the baby may abort but is still live and well inside the uterus. Meaning that there has been no damage to the baby but it may occur anytime. Incomplete abortion: is a condition where the process of abortion has started but it is not complete. Both cases need an ultrasound examination for diagnosis. A threatened abortion can be sometimes stopped using progesterone and HCG injections as well as bed rest. Other causes may be cervical erosions and polyps [non cancerous tumors of the cervix]. These conditions sometimes worsen during pregnancy due to hormone changes of pregnancy. Both can be diagnosed by a vaginal examination. Placenta praevia [ placenta is the part that attaches to the mother and gives nutrition to the baby via the umbilical cord]: in this the placenta lies close to the cervix and causes bleeding. This usually occurs in the second or third trimester but may occur in the late first trimester. Placenta praevia can also be diagnosed by ultrasound. So I suggest that you do not ignore this symptom, see your healthcare provider and get an ultrasound and examination as soon as possible. Hope this satisfies your query. Thanks for using HCM. Feel free to ask any more questions that you may have. Dr Madhuri Bagde Consultant Obstetrician and Gynecologist