We have an update from Keitany's agent who confirmed that the 'problem' that Keitany referred to was indeed her period - her first in 3 months. We've added that to our recap as shown below.
QT: Mary Keitany was not 100%
Shalane’s final four miles were so good, we’re not sure Mary Keitany could have beaten Shalane Flanagan if Keitany had been on top of her game, but after the race Keitany revealed she wasn’t 100% and that she developed a “problem” yesterday, that caused her to not use her front-running tactics. Keitany said, “Yesterday afternoon I had a problem, and that's part of life because I experienced this at 3:00 p.m. yesterday, and I was not able today to deliver what I wanted.” We’re assuming Keitany started having her period, and will update this if we received more information.
UPDATE: We reached out to Keitany’s agent, Gianni Demadonna, and he confirmed that Keitany received her period on Saturday afternoon for the first time in three months.
“Today in the race she was never feeling ok and the body was tired and without energy when she was trying to change the pace,” Demadonna wrote. “She was not even by far the real Mary Keitany. She said the body was not responding at all. Believe or not believe this is the reason she was running so poor to compare to her normal standard today.”