Slight spotting after contact is a possibility after intercourse during first three months specially so if the placenta is low lying . Take rest and avoid IC till there is no more bleeding for a week atleast and the placental localization has been confirmed as not low lying. Should the scan reveal a low lying placenta , then avoid Ic throughout pregnancy or till a time when the placenta has naturally migrated towards the fundus (top ) of the uterus. Needless to say IC should be gentle to avoid any type of placental separation causing vaginal bleeding and jeopardy to the baby.