On the Pulse

Fetal Care and Treatment Center Performs Successful First Laser Ablation Procedure for Twin-to-Twin Transfusion Syndrome

11.1.2022 | Bob Sable and Seattle Children's Press Team

Two babies on a blanketKatie and Nic Harmston were distraught as they drove to Kaiser for an ultrasound in July 2021. Katie was six and a half weeks pregnant but was experiencing symptoms of a miscarriage. They both feared the worst.

The Harmstons held their breath as the ultrasound began. After a moment, the sonographer smiled and said, “We have a heartbeat.” Katie and Nic were nearly overwhelmed with relief. Then the sonographer said something unexpected.

“Hold on — there are two heartbeats!”

“We were shocked to find out it was twins,” Katie says. “I just started crying and laughing.”

A Heart-Sinking Diagnosis

Katie and Nic were sent to Swedish Medical Center for specialist care. During week 12, an ultrasound revealed the twins were monochorionic diamniotic — they shared a single placenta but had separate amniotic sacs. The shared placenta meant a higher risk of complications like premature birth, low birth weight, anemia and other conditions, including twin-to-twin transfusion syndrome (TTTS).

Test results were good over the next month, which raised their hopes. Then came the week 16 ultrasound.

“They weren’t saying anything during the ultrasound,” Nic recalls. “Afterward, the doctor said, ‘We’re going to send you to Seattle Children’s because you have twin-to-twin transfusion syndrome.’ Our hearts sank.”

Typically, each baby in the womb has its own vessels that carry blood and nutrients from the placenta to the baby and back to the placenta. In TTTS, abnormal vessels connect the babies’ circulation, causing one baby (the donor) to pump blood to the other (the recipient). Without treatment, both babies are at high risk of dying in the womb.

In Excellent Hands

Katie and Nic were referred to Seattle Children’s as the Fetal Care and Treatment Center was launched in October 2021. The center is a game-changer for families in the Washington, Alaska, Montana, Idaho and beyond. It combines the existing Fetal Diagnosis Program, which provides testing, education and counseling for families when a developing baby has a health concern, with Seattle Children’s and The University of Washington School of Medicine’s new Maternal Fetal Intervention and Surgery Program, which enables Children’s to treat certain conditions prior to birth.

Dr. Bettina Paek and Dr. Martin Walker co-direct the surgery program with Dr. Rebecca Stark and are specialists in fetoscopic laser ablation — using a laser to close the abnormal blood vessels connecting the circulation of babies with TTTS. They are the only physicians in the Pacific Northwest who perform this procedure and they have some of the highest survival rates in the U.S.

For the next month, Katie and Nic came to Seattle Children’s twice a week for tests, and the babies remained stable during that time. The Seattle Children’s team told the Harmstons that if one final set of scans came back normal, they would “graduate” from the program without needing surgery. Things finally seemed to be going their way.

A Curveball

Katie and Nic came to that final appointment with high hopes, though unfortunately something was wrong once again. The sonographer couldn’t see a bladder in the donor baby, and excess amniotic fluid had collected around the recipient.

“TTTS can skip stages,” Dr. Paek explained. “So, we had to throw them a curveball and say, ‘We have to do surgery tomorrow.’”

Katie and Nic were heartbroken but also determined. “We decided, ‘We’re going to get it fixed, hope for the best and be done with these checkups,’” Katie said.

The procedure took place the next morning at UW Medical Center — Montlake so Katie could recuperate there afterward.

Katie was the first Fetal Care and Treatment Center patient to undergo a laser ablation procedure for TTTS. Dr. Paek and Dr. Walker closed 15 abnormal blood vessel connections, which is about twice the number as most TTTS cases.

The surgery went well, but one major test remained: an ultrasound the next morning to learn if the babies survived.

“It was a terrifying couple minutes waiting for that ultrasound to get hooked up,” Nic says. “But thankfully, the sonographer was Robin Henderson, who had been our sonographer for weeks, and Dr. Paek was there as well. That was comforting.”

The ultrasound detected two strong heartbeats. The babies’ fluid levels were normalizing, too.

Filling a Gap

Fetoscopic laser ablation is a prime example of the new procedures Seattle Children’s plans to offer through the Maternal Fetal Intervention and Surgery Program. But that’s just the beginning.

“We hope to provide fetal myelomeningocele repair for spina bifida,” said Dr. Stark. “After that, we hope to offer fetoscopic endoluminal tracheal occlusion for fetuses with severe congenital diaphragmatic hernia.”

The collaboration between Seattle Children’s and UW Medicine is a critical component of the Maternal Fetal Intervention and Surgery Program, which offers the next generation of fetal care for families in the Northwest and beyond. Care is provided at both Seattle Children’s Fetal Care and Treatment Center and UW Medical Center — Montlake through the Maternal and Fetal Medicine Program.

“We’ve had a gap in the Pacific Northwest with fetal intervention,” Dr. Stark added. “Both UW Medicine and Seattle Children’s have stepped up to fill that gap.”

“So much of your health and well-being is determined in the few months before you’re born,” Dr. Walker said. “For too long it’s been ignored. It’s not being ignored anymore, and we’re happy to be part of that.”

A Happy Ending

Juniper (June) and Hazel were born at 33 weeks and 4 days. They went straight to the Seattle Children’s Neonatal Intensive Care Unit (NICU), where they grew and learned to eat so quickly that they were released after just 15 days.

Their journey involved an array of professionals from many healthcare organizations, but the Harmstons are especially quick to praise Seattle Children’s.

“The best part was going to Seattle Children’s,” Nic said. “We went from being terrified to feeling comfortable. Seeing the same four people each time really helped.”

June and Hazel are unphased by everything they went through. They have no health issues and their growth is back on track with that of full-term babies.

Throughout their ordeal, Katie and Nic remained strong and positive. Now they’re basking in the joys of parenthood — even the exhausting parts.

“We’re not getting much sleep right now,” Nic said. “But that’s okay. Things are normal here.”

And that’s just the way they like it.