Her attorney, Mickey McDermott, believes she was raped while taking sedatives prescribed for the treatment of seizures.
However, her brother argues the woman, a US National Guard veteran, never had seizures before going to jail.
"It had to happen at night when she was unconscious after she took her medicine, because that's when they gave her her medicine – at night," her brother Terrell Ransaw told CBS.
"She's giving birth to a child she didn't plan to have. Nobody asks to be raped or drugged.
"Just because a person is locked up doesn't mean they're a bad person or did the crime you say they did."
The pregnancy is reportedly under investigation.
Daniel was in prison after being accused of being the getaway driver in a fatal shooting. She is charged with capital murder.
She has been transferred to a different jail.