From Last Train to Memphis: The Rise of Elvis Presley by Peter Guralnick:
1962: Elvis was romancing both of his costars, the voluptuous, Toronto-born Helm and the southern beauty Joanna Moore. Of the two, he had an easier time with the down-to-earth Helm Elvis had become frightened of Joanna Moore.
According to Joe Esposito, her reputation for promiscuity preceded her on the Follow That Dream set, and “sure enough, they went off together.” The affair was short-lived, however, because Elvis found her strange. She spoke in a voice that was both high-pitched and tense, and she was far too effusive with both the guys and with Elvis, declaring her love for him almost immediately.
When she became clingy, he quickly moved on to Anne However, when filming resumed in California, Joanna was not to be ignored. She showed up at Elvis’s door late one night, looking terrible, “as if she’d just climbed out of bed,” Joe remembered. Slurring her words, she demanded to see Elvis.
When Joe told her Elvis was asleep, she began crying and tried to force her way into the house. She passed out in Joe’s and Charlie’s arms, and after Charlie got a wet cloth and revived her, Joe asked her what could be so important that couldn’t wait until morning.
“Elvis got me pregnant,” she moaned. “And I took a bunch of sleeping pills. I have to talk to him!”
Charlie and Joe took her to the UCLA Emergency Room, where doctors pumped her stomach.
The next morning, the guys told Elvis what had happened. “Make sure you call and find out how she’s doing today,” he said. “I knew that girl had problems. That’s why I stopped seeing her.”
As for the pregnancy, Joe says, the doctors saw no evidence of it.