If she gets her period on the 30th of each month, her menstrual cycle is 30 days. Based on her menstrual cycle, we can calculate that her safe period is from day 15 to day 28. However, the safe period is not absolutely safe, as women's menstrual cycles may be affected by many factors, such as mood swings, health conditions, and drug use.

Having sex during ovulation may increase the risk of pregnancy, but that doesn't mean it's impossible to get pregnant. If she wants to get pregnant, she should make sure to have intercourse during her ovulation period and take appropriate safety measures, such as using condoms or taking oral contraceptive pills.

To sum up, for a woman who gets her period on the 30th of every month, her safe period is from the 15th to the 28th day, but she needs to make sure she has sexual intercourse during the ovulation period. If she wants to get pregnant, she should make sure to have intercourse during her ovulation period and take appropriate safety measures.