If a person gets their period on the 4th, their cycle is usually 28 days. This means they menstruate every 7 days and each period lasts 4 days.

So, if a person gets their period on the 4th, their ovulation period should be between the 14th and 20th of the next month.

Please note that this is only a general time frame, as everyone's cycle is different, so exact dates may vary. If a person wants to get pregnant, they should try to have sex as close to their ovulation date as possible and have sex on that day.

Hopefully this helps people better understand how to get pregnant. If you have any other questions, please feel free to ask me.