Michelle and Jim Bob Duggar's nineteenth child is back in the hospital after spending less than a few days at home.

Josie Brooklyn Duggar -- who was born in December three months premature -- was taken back to Little Rock's Arkansas Children's Hospital on Thursday at 3AM after her vital signs began to drop unexpectedly, People reported Monday.

"[Josie's attending physician Dr. Robert Arrington] told us to never trust a preemie," Jim Bob told People. "That is really true."

The reason why the youngest member of the 19 Kids and Counting clan had to be taken back to the hospital was that her vital signs began to fluctuate due to constipation caused by fortifiers added to breast milk to increase her calorie intake, Jim Bob told People.

"She's doing fine now," he told People. "They will watch her for a few days to make sure she's safe."

Josie was delivered via emergency C-section at the University of Arkansas for Medical Sciences and weighed 1 lb., 6 ounces when she was born in December.

While Michelle was not due until early March, she was taken to the hospital to have a gallstone removed. The pain from the gallstone caused Michelle to have early contractions, leading to the early arrival of her nineteenth child.

Josie was taken to her family's temporary Little Rock home last Tuesday, however since she immediately returned to the hospital doctors are currently trying different combinations of fortifiers to make sure she doesn't have to come back so quickly.

"It seems like she will do great for a few days and then have challenges," Jim Bob told People.

"We are so encouraged about how she's doing, and it is amazing how she's filling out. But, even though she is beyond her due date and over the four-month mark, she is still not at the weight of a full-term baby."