At 7 months old, identical twin sisters Kensley and Berkley are rolling over and making a lot of noise. The only visible clue that these are not your average babies is their size. Kensley is 13 pounds while Berkley weighs 11. Even in the womb Kensley has always been bigger -- a fact that once threatened both babies' lives.
"Medically, these babies, should not be here, and miraculously they are," said mother, Laura Ballard of Parker, Colo.
Kensley and Berkley survived an extremely rare, yet increasingly common, condition known as twin-to-twin transfusion syndrome, which occurs in identical twins when they are in the womb.
Laura and her husband Todd Ballard's saga began when the couple learned that after two and a half years of unsuccessfully trying to bring another child into the world she was carrying twins.
But Laura Ballard's doctor could not tell if the two shared the same placenta, so at 14 weeks she went to a specialist. The doctor told the couple that not only were the twins identical, but also might have twin-to-twin transfusion syndrome.
"Already at that time, one baby had much less than normal fluid around it, and one had a lot more. They were different in size," said Dr. Craig Stark, the couple's perinatologist.
All the blood, oxygen and nutrients that circulate within the baby are delivered through the placenta. It is essential during fetal life that this flow of nutrition and oxygen is maintained in a balanced way.
In babies suffering twin-to-twin transfusion syndrome, the placenta begins to shunt more of its blood to one baby and away from the other. Essentially, the babies' blood supplies become connected and one baby begins donating its nutrients to the other.
This is dangerous because one baby -- in the Ballards' case, Berkley -- basically stops growing and its internal organs begin to suffer. Kensley, meanwhile, began to grow faster than normal.
One of the most severe consequences of this condition is stuck-twin-syndrome, where one baby is so small that its kidneys don't develop the way they should, leaving less fluid around the baby that would help cushion it and help it exercise.
On the other hand, the other baby's growth is so fast that it often leaves the child with swelled organs and an increased likelihood of premature birth or death.
"He [the doctor] said, 'Don't Google it,' and the first thing we did when we left was Google it," Ballard said. "From there it was horrifying. I felt pretty much that there was no hope. I was so afraid and wondered at what point they would pass away, and when I would have to deliver them silently into this world."
Without treatment, both babies die 90 percent of the time.
In the past, the principal treatment for twin-to-twin transfusion syndrome has been to drain fluid from the bigger baby to try to allow improved balance. The hope is that the increased balance in the blood flow that the placenta provides will help both, but the success rate has been variable. Laura Ballard tried that method unsuccessfully four times.
Dr. F. Sessions Cole of Washington University in St. Louis said that in instances like the Ballards' there is little a parent can do to avoid the condition.
"We have no idea why the placenta does this. As for treatment, there is no clear right or wrong answer," Cole said. "Each patient has their own risk factors. A parent has to trust who they are dealing with, and the physician should give as much info about not only the treatment but also its positive and negative side effects for the particular babies."
"Laura's very pushy when she needs to be. She pushed and she researched," Todd Ballard said, choking up as he recalled his families ordeal. "She was always pushing the envelope to save her babies."
The couple was told that besides draining fluid in the womb, there was a new, riskier method of treatment that involved twin-to-twin laser therapy. In that treatment, which is performed in only a select number of hospitals nationwide, doctors take a laser and fetus scope and look at the placenta.
"Both the treatments involve a needle. The laser therapy is more invasive. It carries a higher risk than simply draining fluid," Cole said. "There are some who try a combination of both. The decision is always based on how badly the babies are affected, and what stage of the pregnancy the baby is."
Doctors then use a laser to try to disrupt or block blood vessels that are contributing to the unbalanced blood flow. The treatment was described as a potential death sentence for the smaller Berkley.
"It really did seem like a last resort. But at 22 weeks my doctor said it's time for us to go," Laura Ballard said.
With Mother's Day looming, the couple left their other three children behind and traveled to the University of California, San Francisco, for the surgery.
"They had talked about lasering Berkley's supply altogether in an effort to save Kensley. We told them we did not prefer for that to happen, but if that was the only option than it was OK," Ballard said.
The surgery lasted an hour and a half. Nine weeks later, she delivered both girls.
Researchers are still trying to determine the root cause of twin-to-twin transfusion syndrome, which only affects identical twins. Cole said that for families facing this crisis and deciding whether to risk laser therapy there is one important thing to determine first.
"Make sure that the facility you choose is not only able to take care of the mother and the baby if things go well, but also if it doesn't," Cole said.
Laura Ballard's advice is simple.
"Don't give up," she said. "Just fight and fight for your babies. There is hope. You are not going to know until the end. But you can only do as much as you can, and the rest is in God's hand."