Children's Hospital Colorado

Harlowe: Caring for a Rare Cardiac Condition, Before and After Birth

Harlowe, a young girl treated by Dr. Bettina Cuneo at Children's Hospital Colorado, rides a horse.

Mariel Corbitt had known for years she had an autoimmune condition, though she was able to manage the symptoms. That’s not uncommon for Sjogren’s syndrome, a disorder that primarily affects moisture-producing glands like tear ducts.

“It never even crossed my mind that there would be complications with my pregnancy because of it,” she says.

For most of her pregnancy, there weren’t. The 20-week ultrasound went well. Mariel found out she was having a girl. She’d name her Harlowe.

Her pregnancy took a turn

At a follow-up appointment a week later, Harlowe’s heartbeat had dropped to half its previous rate. Mariel’s obstetrician immediately rushed her to fetal cardiologist Bettina Cuneo, MD, at Children’s Hospital Colorado.

“It happens in a small percentage of women,” says Dr. Cuneo: Sjogren’s antibodies — tiny agents programmed to attack substances the body recognizes as threats, like viruses and bacteria — cross into the fetal bloodstream and attack the electrical system of the unborn baby’s heart.

“Because the top chambers of the heart can’t communicate with the bottom chambers — a condition called heart block — the fetal heart rate can fall from 150 to 40 or 60 beats per minute,” she says. “That’s one reason more than 20 percent of these babies will die before they’re born.”

Even among the 3 percent of women with Sjogren's syndrome, heart block is rare. Still, as one of the nation’s foremost experts on fetal arrhythmias heartbeats, Dr. Cuneo had experience with the condition.

A plan to save baby Harlowe's life

Dr. Cuneo immediately started Mariel on a combination of therapies to bring down the inflammation and speed Harlowe’s heart rate. She also introduced Mariel to Kathryn Collins, MD, director of the Arrhythmia Center at the Children’s Colorado Heart Institute, who would take care of Harlowe after birth.

Meanwhile, Dr. Cuneo and her team saw Mariel every week. “Our goal was to deliver at 37 weeks when her lungs would be mature and she would be big enough for a pacemaker,” says Dr. Cuneo. “Thirty-two weeks was a big milestone since by that time all the major organs except the lungs are functioning normally, but we hoped for more time.”

By 33 weeks, though, despite the medications, Harlowe’s heart rate had dropped lower than ever. It was time. Mariel delivered via caesarean section at the Colorado Fetal Care Center at Children’s Colorado.

Born just the right size

Newborn Harlowe weighed 4 lbs. — just big enough for pediatric cardiothoracic surgeon Max Mitchell, MD, to implant a pacemaker. Harlowe underwent the surgery at just four hours old. All she had to do was go from the delivery suite to the operating room, one floor down. Dr. Collins and the intensive care team took over from there.

“The transition went seamlessly,” says Dr. Cuneo.

“We were in the neonatal intensive care unit for 11 weeks after that,” says Mariel. “During all that time we were mostly focused on Harlowe’s breathing and eating and weight gain. Looking back, we hardly thought about her heart. And I think that shows how well it all went.”

Now, at just over 2 years old, Harlowe is still doing well. “She’s feisty,” Mariel says. “I don’t think anyone would ever guess she had a problem with her heart.”

About Sjogren’s Syndrome

In a situation like Mariel’s, if doctors can act within the first 24 hours that the Sjogren’s antibodies cross the placenta, they can quell the inflammation and stop the damage. The problem, Dr. Cuneo says, is that many mothers don’t know they’re carrying the antibodies, and even if they do, many obstetricians don’t know the antibodies pose a danger.

In a successful international study, Dr. Cuneo and colleagues gave fetal heart monitors to 120 mothers with the Sjogren's syndrome antibody and asked them to check their baby’s heart rate twice a day at home. Two mothers caught the inflammation in its early stages, and both babies were born with healthy hearts.

A simple blood test can identify Sjogren's syndrome antibodies, and while the condition is rare, Dr. Cuneo thinks the cost of universal testing is worthwhile. With testing and monitoring for mothers who test positive, doctors could stop cases like Harlowe’s before they start.

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