Kiran Gandhi, 26, let her period flow freely during the 26-mile race in a bid to raise awareness about people who have no access to feminine products.She urged women to embrace that time of the month, rather than hide away in shame.
And after the race, she proudly posed for photographs with family and friends wearing her blood-stained running trousers.
"I ran the whole marathon with my period blood running down my legs.
"I ran with blood dripping down my legs for sisters who don't have access to tampons and sisters who, despite cramping and pain, hide it away and pretend like it doesn't exist.
"On the marathon course, sexism can be beaten.
"If there's one way to transcend oppression, it's to run a marathon in whatever way you want. "Where the stigma of a woman's period is irrelevant and we can re-write the rules as we choose."
After the race, the Havard business school graduate said she was empowered.