Last month my sister had heavy bleeding for 7 days now this month she missed her period home test has done but negative result

How late is her period? Pregnancy tests are less accurate if used before the period is two weeks late. It is also less accurate if first morning urine is not used.

Test has done first morning urine after she missed 5days period she had her sex 4 days before her period.

She needs to be late for her period for at least 14 days. She is testing too early and possibly getting a false negative.

But she does not have children's
From past 10 years is there any
Chances this month

That is not a question I can answer as I am not able to run the necessary tests to make a determination. She will have to see a doctor about that.