The singer and husband Nick Cannon - who became parents to son Moroccan Scott and daughter Monroe on April 30 - were shocked when an anonymous tip to the Los Angeles Department of Children and Family (DCFS) accused her of putting the babies at risk by drinking alcohol and taking drugs in her hospital room.
Mariah - who brought the babies home from hospital two weeks ago - admitted to investigators she drank a Guinness but only on the advice of medical staff who informed her a dark beer would help with lactation.
Laura Wasser - a lawyer for the singer - was present during questioning before the DCFS decided not to pursue the matter, website TMZ reports.
Earlier this month, `America`s Got Talent` host Nick explained the couple were shocked at the "ridiculous" allegations.
He said: "Recently, the Child Protective Services were called with allegations that there was some drinking and drugs and all that going on, wild in the hospital, which makes no sense to me - how would a hospital allow that?
"It all started when a nurse suggested to my wife that if you drink Guinness, the dark beer, the yeast improves breastfeeding. I don`t know if someone heard that, but then they were saying my wife was drinking beer. People will do anything to try to conjure up a story.
"I spoke to the person from the Child Protective Services, I was like, `This is ridiculous. We`re going to make sure that this isn`t a case.`
"To even have to deal with that, my wife in the state that she`s in, we`re in the hospital, to even have to think about someone possibly wanting to investigate your children. It`s sad at the end of the day."