But her strong recovery allowed her to just make the final on time.
World record holder Ruth Jebet led the race for the first two kilometers, which saw Kenyan Beatrice Chepkoech accidentally skip a water barrier and then a fall that took down some other competitors.
The leading pack was heavily congested heading into the last 200 metres.
No American woman has ever won a medal in the event at worlds and no American pair has swept a distance event at the World Championships or Olympic Games since 1912.
"I have memories from 2015 and 2016 where I went too early for the last push, so I just had to keep trusting myself and be patient, and it looks like it paid off".
Until Friday, no American woman had won a medal in this event at the world championships. "It is pretty wonderful to get a championship record", she added.
Pearson won the heat in 12.53 seconds, .24 seconds faster than Nia Ali of the United States. Maybe fifth or sixth, but silver? "This is an absolute dream", Frerichs said.
Amidst all that it was Jebet who was controlling that pace, with Jepkemoi sitting behind her and with the American duo both sitting in comfortable positions.
Team USA will go home feeling like they have upset the 3,000m steeplechase status quo, with Coburn and Frerich's medals adding to Evan Jager's landmark bronze in the men's event on Tuesday.
Defending champion Hyvin Kiyeng Jepkemoi was unable to retain her crown but finished third 9:04.03.
"I'm so happy to have won alongside Emma".
Miller-Uibo was 0.07 seconds adrift in third place, her bronze medal - her first over this distance at either the Olympic Games or World Championships - offering some consolation from a hard Championships.
The former Olympic champion from Australia missed much of the past two seasons because of injury, but she produced the fastest time tin the semi-finals.
The 26-year-old made an inexcusable mistake as she ran past the first water jump without actually leaping over the hurdle.