Sometimes, there is an infection in the pelvic cavity or may be in the urinary tract. These infections could also be the cause of bleeding or spotting during pregnancy early trimester. After having intercourse, bleeding in some of the women is also observed as their cervix is weak, tender or sensitive enough. Light spotting during pregnancy could also be due to molar pregnancies which may grow chronic. Molar pregnancies could be the cause of bleeding in early pregnancy but it is rare. Some of the signs of the molar pregnancies are: HCG levels are high, vaginal bleeding, grape like clusters and no fetal heart tones. In such pregnancies, abnormal growth of tissues starts occurring instead of growth of embryo.