dusty pink pastel dresses for bridesmaid

Hi guys sorry me again!
Could I have a post to the correct page, posting for my sister..my sister had unpretected sex on the 13/7/17 and has had a few early pregnancy symptoms. She's tired, feels sick and hormonal, now she's got brown/pink discharge. She only had sex once but it was 2 weeks after her period. What are the chances she's pregnant? Like 50% or 30% if that sounds alright dusty pink pastel dresses for bridesmaid ???? x