A first-time mother gave birth to a rare set of identical triplets, which were reportedly conceived without the use of fertility treatments.

According to FOX 59 News, Chad and Amanda Doss of Franklin, Ind. welcomed baby girls Avery, Bentley and Cassidy Doss were born on Monday at St. Vincent Women's Hospital.  According to multiple reports, the likelihood of conceiving identical triplets in one in100 million.

"Of the last probably 20 or so years, I've taken care of probably 200 sets of triplets. And out of those she's the third that I recall to have identical triplets," Dr. James Sumners, Amanda's primary care physician during the pregnancy, told FOX.

Amanda knew from the beginning of her pregnancy hers was different as she felt she was "bigger" than most.

"I kinda felt like I was getting bigger faster than most people that I knew," she explained to FOX.

The husband and wife found out they were having triplets during a doctor's appointment to find out the gender of their baby.  Amanda was in denial and told the technician she couldn't be having more than one, but the ultrasound proved they were having triplets.

Amanda's pregnancy was closely monitored by her physician, and was admitted into the hospital in December when she began having contractions, but "couldn't feel them," according to FOX.  The triplets were due in February, but the family knew it was likely the babies would come early.

Avery weighed 3 lbs. 15 oz., Bentley weighed 4 lbs. 3 oz., and Cassidy was the smallest weighing in 3 lbs. 11 oz. 

"I'm just happy they're here and healthy," Amanda told FOX.

Though the girls are identical, Amanda and Chad notice they're already showing their different personalities.

The couple told FOX Avery is the most alert, why Cassidy keeps to herself and Bentley is reaching her milestones the fastest, as she has already lifted her head.

Click here to view photos of the rare identical triplet girls.