Terminally ill Brittany Maynard, 29, to use Oregon law to end her life

Brittany Maynard will not live to see if her advocacy makes a difference.

The 29-year-old US woman expects to die no later than November 1. If the brain cancer from which she suffers does not kill her this month, she plans to take advantage of Oregon's Death with Dignity Act and end her own life on the first day of November - a few days after her husband's 30th birthday.

Maynard and her husband, Dan Diaz, uprooted from California and moved north because Oregon allows terminally ill patients to end their lives with lethal medications prescribed by a doctor.

Rather than silently await death, she has become an advocate for the group Compassion & Choices, which seeks to expand death-with-dignity laws beyond Oregon and a handful of other states.

A nationwide media campaign featuring Maynard's story began on Monday and has gone viral.

"I can't even tell you the amount of relief that it provides me to know that I don't have to die the way that it's been described to me, that my brain tumour would take me on its own," she says in an online video.