An expectant mother undergoes a C-section as she was going to give birth to conjoined twins in Colorado. Amber McCullough, before her delivery, said she wants to see both of her baby girls before they are separated. According to doctors, there are only a few chances of success.

Amber McCullough, of Hastings, Minn., was scheduled to have a C-section Wednesday to deliver twin girls at the Colorado Fetal Care Center at Children's Hospital Colorado.

As per doctors, who performed the C-section, the twins, Hannah and Olivia, share an abdomen, liver and intestinal tract, but the girls have separate hearts and kidneys.

McCullough told KUSA-TV that Olivia is not expected to survive due to her heart. She only has a single ventricle, and is missing valves. Doctors said it would take nearly 12 hours to separate the kids.

McCullough said, "I will get to see my girls very briefly after the delivery. They will need to be intubated right away, but the doctors will hold them up real quick and I'll get a peek".

Conjoined twins happen once every 200,000 live births, according to the University of Maryland Medical Center, which says between 40 to 60 % arrive stillborn.

McCullough said she has spent nearly eight years in the US Army, after which she went to law school, and is now an attorney. She has a 6-year-old son named Tristan from a previous relationship.

She became pregnant with her girls during another relationship. It was in her second trimester when she learned that she was carrying conjoined twins. Her relationship with the girl's dad ended shortly thereafter.