Cynthia Calvillo missed weight by two pounds at the UFC Argentina weigh-ins Friday morning. Later Friday night, the popular UFC women’s strawweight fighter explained what happened in a statement issued to MMA Fighting’s Guilherme Cruz.

Calvillo, who looked frighteningly unsteady while getting on the scale, said she and her nutrition team foresaw a potential issue coming into the week, because they knew she might get her period. Despite knowing that could throw the weight cut off and preparing for it, Calvillo said it didn’t matter. She said she was not able to sweat at all this morning when she woke up to shed the extra pounds.

“Basically what happened is I started my period this week,” said Calvillo, who weighed in at 118 pounds. “We were kind of prepared for it, because we could feel the symptoms, but unfortunately this morning when we got up it was about 5:30 and I had two pounds to go. Then, I couldn’t cut any weight at all from 5:30 to 8 a.m. We tried everything and I could not break a sweat. Even when I got up to the scale, I was the same weight that I woke up at 5:30 in the morning.”

Calvillo was cleared by Brazilian MMA Athletic Commission (CABMMA) doctors and her scheduled fight with Poliana Botelho will go on Saturday in Buenos Aires. Calvillo was fined 20 percent of her purse for missing weight.

“They decided to go ahead and stop me from continuing cutting the weight at 9 a.m.,” Calvillo said. “They didn’t want to make me suffer more so that I was still able to fight. So, that’s basically what happened. Unfortunately, we tried to prepare the best for it, but my body was just not sweating due to having to retain the water because of my period.”

Calvillo (6-1) is coming off a nine-month Nevada Athletic Commission (NAC) suspension for failing a drug test for cannabis last December. Prior to that and a loss to Carla Esparza at UFC 219, the Team Alpha Male product was thought to be a top prospect at 115 pounds. Calvillo, 31, had won three straight in the UFC, including two submission finishes, before the defeat to Esparza.