Under the Law of Moses, Jewish women were considered to be impure for seven days during the period of menstruation and there were various requirements regarding separation and washing during this time, as listed in Leviticus 15:19-24. In Leviticus 18:19 and Ezekiel 18:6, sexual relations during this period are prohibited.
In the New Testament there is no reference to impurity at the time of menstruation. Some churches may have their own regulations and if you are concerned you should check.