Sanya Richards-Ross reveals in her new memoir, "Chasing Grace," that she had an abortion the day before leaving for the 2008 Olympic Games in Beijing, China.

The American was the gold medal favorite in the 400m, but she had to settle for bronze after leading the field through the first 300m and getting passed on the homestretch by Christine Ohuruogu of Great Britain and Shericka Williams of Jamaica. She led Team USA to gold in the 4x400m relay.

At the time, Richards-Ross was just Richards -- 23 years old and newly engaged to Aaron Ross of the New York Giants with a wedding date set for 2010, after the whirlwind of the 2008 Olympic Games and 2009 IAAF World Championships. The two started dating in 2006 and used natural family planning as their preferred method of birth control after her body reacted negatively to using a NuvaRing.

"I thought about taking the pill, but I'd seen so many teammates struggle with the water weight and changes in their body that I feared the adverse effects it might have on my speed and endurance," she writes in the book. "I wanted to do the right thing and protect myself from unplanned pregnancy, but I was unaware of all my birth control options and ashamed to talk to my mother or coaches... I was naive and in love... we trusted our plan had no issues and believed my high training load and low body fat also controlled my hormone levels."

Richards-Ross found out she was pregnant one month before the Olympic Games. Ross was already back at training camp with the Giants "and nothing interrupted (New York coach) Tom Coughlin's schedule for the Super Bowl champions," so she went to the hospital for the abortion without Ross. The doctor recommended two weeks without activity, but instead, Richards-Ross boarded the 15-hour flight bound to Beijing the very next day.

She won her preliminary and semifinal rounds of the 400m in 50.54 and 49.90 before earning the bronze medal in the final in 49.93. Ohuruogu's winning time was 49.62.

Richards-Ross would go on to win double gold in the 400m and 4x400m relay the following year at the IAAF World Championships and then again at the 2012 London Olympic Games. 

Though Richards-Ross is the first high-profile female athlete to admit to having an abortion when an unplanned pregnancy conflicted with the four-year Olympic cycle, she says that she is far from the only one to do so.

"Most of the women I knew in my sport have had at least one abortion," she writes in her memoir. "Prioritizing athletic goals over the gift of life was the norm. It was all around me, but not until it was me did I realize many of these young women only wore a mask of indifference for something I can now testify requires deep thought and proper counsel."

Richards-Ross said on a podcast that she prayed for almost two years before deciding to reveal her abortion to the world.

"Ultimately, I did it to glorify God and to tell people that you can come back from any decision no matter how hard it is to make… you can still have God with you on the journey," she told the podcast.

Richards-Ross retired from competitive running in 2016 after failing to qualify for the Rio Olympic Games, but she has quickly transitioned into the next phase of her career. She helped commentate the Olympics as an on-air broadcaster and has appeared on other track and field broadcasts for NBC. She and Ross are expecting their first child.