Amber McCullough, of Hastings, Minnesota, gave birth to conjoined twins Hannah and Olivia via c-section on Wednesday but due to the severity of the girls' heart condition, doctors had to immediately conduct a complicated surgical operation needed to separate them.

One of the twins, however, was not lucky to survive.  Elizabeth Whitehead, the spokesperson for the Children's Hospital Colorado, said on Thursday that Olivia died after the five-hour separation procedure.

Despite the saddening news, the children's mother, who is now recovering, remains hopeful. The twin who survived, Hannah, on the other hand, is in critical but stable condition.

"I believe in the power of prayer and the talent of the medical professionals here," said McCullough.

McCullough also has a 6-year old son from a marriage that ended in divorce. She became pregnant with the twins in another relationship that has also ended.  In a message sent to KARE 11's Lindsey Seavert, McCullough has asked people to pray for Hannah.

"She is very critical and very delicate. So what I would like is to appeal to as many people public for prayer," McCullough said. "Could you please ask that the public pray as she waits for her life this week?"

McCullough decided to push through with her pregnancy aware that one of the twins would not likely survive. Olivia was long expected not to make it because of problems with her heart. Hannah has the best chances because she has a normal heart and does not have serious malformations as her twin.  

"The current prognosis is that Olivia will not be able to survive long because she has a single ventricle heart and is missing valves," McCullough wrote on the  GoFundMe account she set up to defray medical expenses. "Olivia also has a Dandy walker varient that will effect her mental cognition."

McCullough has said that she wanted to keep both of the girls but it is not possible because both twins will pass if they stay together.

McCullough, who was with the Army for eight years before she went to law school and eventually became a lawyer, learned of her twin's condition while on the second trimester of her pregnancy.

Hannah and Olivia shared liver, intestinal tract and abdomen albeit they had separate kidneys and hearts. Conjoined twins occur once in every 200,000 live births and 40 to 60 percent are stillborn. Pairs born alive are also often marked by abnormalities that are incompatible with life.

Photo: Amber McCullough