Olivia Wilde is tweeting her baby bump, and she wants you to do the same.The reason? As much progress as we've made in modern medicine and health care, maternal health care remains incredibly high-risk. According to the World Health Organization , approximately 830 women die from preventable causes related to pregnancy and childbirth every day. And yet maternal health doesn't seem to be discussed nearly as often as it should be.One hashtag, however, is hoping to change that. #BumpDay , celebrated on August 3, seeks to raise awareness about the need for maternal health care worldwide. The initiative was started by What To Expect , a site committed to sharing information and news about pregnancy and parenting, in partnership with International Medical Corps , the UN Foundation’s Universal Access Program , and 1,000 Days Foundation "We have so many 'days' now that it seemed to us we needed a day to talk about something that affects literally every human on the planet — healthy pregnancy," What To Expect's editor-in-chief, Diane Otter, tells Refinery29.Throughout the day, the hashtag has seen participation from moms worldwide (including Wilde and Vanessa Williams), and organizations like the United Nations.