This report aired Dateline Sunday, May 20
They were only two months old when we first met them—two beautiful babies: wide eyes, round cheeks, and personality to spare. But these twin sisters were no ordinary babies. Abby and Belle Carlsen were conjoined. Doctors told their mom and dad that without successful surgery they could lose at least one of their little girls.
Rob Stafford, Dateline correspondent: What do the girls mean to you?
Jesse Carlsen, father: Everything. They are my world now.
Jesse and Amy Carlsen were on a quest to give their girls the best chance at life, and they agreed to let Dateline chronicle their journey every step of the way.
Jesse Carlsen: It’s all in the Lord’s hand. I will give it to him and let him take care of it.
It was February 2005 when Amy and Jesse of Fargo, North Dakota learned that Amy was pregnant.
Amy Carlsen, mother: And I was just happy, and we hugged. It was very exciting.
But during an ultrasound, Amy, a nurse herself, noticed the technician was taking too long to explain the results.
Amy Carlsen: I’m laying on the table for maybe an hour she is checking and taking pictures...
Amy had a feeling something was wrong.
Amy Carlsen: And she said, “The babies are conjoined.”
Stafford: The babies are conjoined.
Jesse Carlsen: I get goose bumps just hearing that again.
Amy Carlsen: I was speechless.
The twins were facing each other, and joined from abdomen to chest. Their chances of surviving until birth— just one in 100,000.
Despite those odds, Jesse and Amy were determined to do all they could to bring the twins into the world.
Indeed, on November 29th, Abby and Belle Carlsen were born.
Amy Carlsen: As soon as they came out and they started screaming, they popped them over that sheet and I got to see them and I just started crying. I was happy, so happy.
Stafford: How did they look?
Amy Carlsen: They looked great. They were very healthy little girls.
Healthy… but hardly out of danger. For the next four weeks, the babies remained in intensive care while the Carlsens thought about what to do next for their girls.Video: Carlen conjoined tiwns
Stafford: You want to separate the girls. Why is that so important?
Jesse Carlsen: For a normal life. I want the girls to have as normal a life as possible.
At one month, the girls were well enough to go home. For two rookie parents, it was trouble times two.
Jesse Carlsen: What a pain in the—yeah.
Feeding? Well, at first it was a two-man job. And clothing? Think snaps...
Amy Carlsen: Just buy two of the same outfit snap ‘em together.
But these two new parents were amazed watching two little girls, locked in a permanent embrace, maneuver the closest relationship anyone can have.
Amy Carlsen: They love each other.
Jesse Carlsen: Yeah.
Amy Carlsen: You can see it.
As close as they are, Abby and Belle have very separate personalities. When Belle cries, Abby sleeps. When Abby sleeps, Belle slaps.
Abby is the snuggler, the more sensitive one...
Belle is hyper and likes to stay awake.
Stafford: Belle looks like her eye is a little bit open
Amy Carlsen: She’s peeking...
Little by little, the girls were gaining weight and thriving.
But then one night, at two months old, a freighting scare.
A respiratory infection had left Abby struggling to breathe. The babies were airlifted to a Minneapolis hospital and placed on oxygen.
Days later, Abby was breathing on her own again, but just when that crisis was averted—another emerged...
Belle had stopped gaining weight. She weighed just 7 lbs. compared to her sister’s 11.
Jesse Carlsen: This one is Abby’s chubby leg and this is Belle’s tinier leg.
After spending time researching their medical options, Jesse picked up the phone and dialed the world famous Mayo clinic in Rochester Minnesota.
Jesse Carlson: I asked is there a surgeon or is there someone I can talk to about my twins?
Pediatric surgeon Dr. Christopher Moir took the call. Moir successfully separated two other sets of similarly conjoined twins.
Dr. Chris Moir: The view from the back of the room is—“Yep, looks just like the other ones.” Then you start looking at some of the more detailed information.
Stafford: And what do you think?
Dr. Moir: It gets more and more complex.
It didn’t take long for him to figure out what was wrong:
Dr. Moir: They are failing. Isabelle is feeding Abigail with her digestion.
Stafford: And not getting enough herself?
Dr. Moir: And not getting as much herself.
If they didn’t separate Abby and Belle soon, there was a good chance one or both would die.
Dr. Moir ordered ultrasounds and CAT scans. And the more he looked, the more concerned he became. Each girl had her own vital organs, but their two hearts overlapped, their pancreases joined together, their intestines were entangled, and their livers were fused with a shared blood supply.
Stafford: All of those things are shared?
Dr. Moir: All those things are shared
Stafford: And have to be separated by your team.
Dr. Moir: Big job.
Dr. Moir assembled a surgical team of more than 30 surgeons, anesthesiologists, and nurses. Together they would plan an operation that would be choreographed minute by minute.
There were no guarantees, and he was very frank with the family.
Stafford: What has been the most difficult moment?
Jesse Carlsen: When the doctor was in th room and basically gave us the percent chance of them surviving. And that just sent chills through my spine. He told us they have 80 percent chance.
For Amy, the stress was taking its toll.
Amy Carlsen: It's finally arriving, its getting closer. And its just, a lot of anxiety.
When the babies were four months old, Dr. Moir set a date for surgery: May 12th.
Stafford: How many things can go wrong in this operation?
Dr. Moir: I don’t even want to count. I can’t count.
Stafford: It’s a lot.
Dr. Moir: I think about it everyday, every night…
Stafford: What will it mean to you if you’re able to give these two little girls freedom?
Dr. Moir: To know that we have come together to help them is something I can take with me forever.
While the doctors prepped, the girls got down to work too, getting tissue expanders implanted to stretch their skin before surgery. They also went through physical therapy to strengthen rarely used muscles.
To pass the time, the Carlsens took the girls for rides to the hospital’s chapel, where Amy would sign the prayer request book.
Amy Carlsen: I put for prayer request for strength and hope before surgery.
And her prayers seemed to be working: surgery was now three weeks away, and Belle was gaining weight, catching up to her sister. Dr. Moir upped the odds of success.
Finally on May 11th, the babies 5 months old, everything was in place. Surgery would begin the following morning.
Stafford: What will you say to the girls when they go to surgery?
Amy Carlsen: We’ll say a prayer and kiss them and say I love them. Love you. And, be strong.
Stafford: What do you think that moment will be like?
Amy Carlsen: Well, just thinking about it now just gives me tears.
Jesse Carlsen: It’ll be tough.
Amy Carlsen: It’s just really very scary. I’m very terrified right now. The girls are the world to me.
Friday morning May 12th, Jesse and Amy carried their babies to the operating room, joined together for the last time. It was the moment the Carlsens have prayed for, but it was the moment they’ve most feared.
Once in the operating room, mom and dad lay the twins down on the table. Before long, a mask is placed over each baby’s face.
Doctors expect surgery will last 12 hours from start to finish.
Video: Will the surgery be successful?
Rob Stafford, Dateline correspondent: What will it be like holding them separately?
Jesse Carlsen: It will be a wonderful feeling.
Stafford: What’s your biggest fear?
Amy Carlsen: Death. That’s my biggest fear.
Stafford: How do you prepare yourself for that?
Amy Carlsen: I know it could be possible.
Jesse Carlsen: Whatever does happen, I guess basically that’s the way it was meant to happen. And, I truly believe that these girls are gonna make it through the surgery just fine.
Dr. Moir is lead surgeon. Each of the twins has her own medical team—Abby is always on the left, Belle on the right.
Stafford: If heaven forbid something does go wrong, how will you explain that to the family?
Dr. Moir: We know it had to be done. We know we did our best.
Stafford: How will you handle that?
Dr. Moir: I would grieve right with the parents.
6:30 a.m.—the anesthesiologist begins to puts the babies under. Temperature, heart rate, blood pressure… all their vital signs are monitored.
Down the hall, Jesse, Amy and their families wait. It will be a very long day but they are surrounded by their loved ones.
9:45 a.m.: Doctors make the first incision, separating the chest wall. Immediately they see the two separate hearts. Remember, Abby and Belle’s hearts overlap, with belle’s heart going partially into her sister’s chest. They must be separated.
Separation goes well, but now an even trickier part—as doctors push belle’s heart back into her own chest wall cavity, her blood pressure begins to drop. They try different positions—finally, they get it exactly in the right place. She’s stable.
1:30 p.m.: Almost 4 hours into surgery, it is time for the most dangerous part—the separation of the liver. Abby and Belle’s livers are fused with interlocking blood vessels. If doctors cut through one of those, the babies could bleed to death .
Using highly specialized equipment, they slowly make their way through this complex procedure, without no mistake.
The separation of the girls livers is complete.
And at 2:50 p.m., after more than eight hours of waiting, Jesse and Amy are able to share some good news.
Amy Carlsen: All organs are separated other than the skin on the bottom that holds them together and they’re fine.
3 p.m., only one more piece of connective tissue holding the babies together...
Doctors prepare for this big moment.
Dr. Moir: We are going to look at our reconstruction before we do anything further...
A little after 4 p.m. they begin.
After almost 7 hours of surgery, the tissue connecting Abby and Belle is finally cut.
The twins are now completely separate.
Very carefully, doctors begin to move Abby onto her own bed. It will be another few hours until reconstructive surgery is complete.
The Carlsens receive the news:
Amy Carlsen: We got two separate babies!! (applause)
Finally the moment Jesse and Amy have prayed for has come true.
Almost 10 hours after surgery began, the operation is over.
Stafford: Do you think the girls will miss each other?
Amy Carlsen: I have a feeling they will miss each other. I feel they will always have a special bond throughout life too.
Belle is moved to intensive care, where she will join her sister. Mom and dad see her for the first time since separation.
The excitement seems to leave Amy in a state of shock.
For now both babies will rest on ventilators.
Dr. Moir: This afternoon they began their separate and wonderful beautiful lives.
There is great admiration for the doctors who have saved the Carlsen babies.
Jesse Carlsen: Today a lot of our prayers have been answered. And I can’t say thank you enough for, helping our girls. Thank you all.
Stafford: What do you want for your girls?
Jesse Carlsen: The world. Anything they want.
And earlier this week, their dream came true. They finally held Abby and Belle in their arms—separate at last.
© 2013 NBCNews.com Reprints