Surgical Team Separates ‘Once-in-a-Lifetime’ Conjoined Twins

Perinatologist David Miller, MD, has almost seen it all in more than 30 years of practice. Of course, he knows that as the Director of the Fetal-Maternal Center at Children’s Hospital Los Angeles, which treats the rarest and most complex fetal abnormalities, that’s the most he’ll ever be able to say—he has almost seen it all.

“Other hospitals send us cases that cause them to scratch their heads,” Dr. Miller says. “So seeing something that I haven’t seen before isn’t as unique as you’d think. If ultrasound doesn’t teach you humility, it won’t teach you anything.”

He was reminded of that by the case of Olivia and Lainey, two twins conjoined at the lower abdomen, sharing intestines, and classified as monochorionic diamniotic, or mono-di—meaning they had the same placenta but separate amniotic sacs. Conjoined twins are rare enough; mono-di conjoined twins are a near impossibility.

“There are maybe only five cases ever reported,” Dr. Miller says. “It contradicts the normal explanation for conjoined twins. Conjoined twins are supposed to develop in a way that everything is one. One placenta, one sac. Most doctors are not going to see this ever in their careers. I’d never seen it.”

Fetal-maternal specialist makes a diagnosis

When the twins’ mother, Aubree, visited Dr. Miller for the first time midway into her pregnancy, none of this had been determined yet. Aubree’s local maternal-fetal doctor could only say definitively that Aubree was having twins. Beyond that, the imaging was inconclusive.

After viewing the scans in his office, Dr. Miller had several suspicions, one being that the twins appeared to each have an omphalocele, a defect that results in the fetus’s intestines bulging outside the body through the belly button. He also saw some possible evidence of evolving twin-twin transfusion syndrome (TTTS), an imbalance of blood flow between two twins in utero.

To get a solid diagnosis, Dr. Miller sent Aubree to see fetal surgeon Ramen Chmait, MD, Attending Physician in the Fetal-Maternal Center and Director of Los Angeles Fetal Surgery.

“One of the biggest things we do is take care of complicated twins,” Dr. Chmait says.

Dr. Chmait saw something else on the ultrasound, something decisive—and exceedingly rare. He was able to rule out TTTS and found that rather than having an omphalocele, the twins were attached at the intestines, a type of conjoinment called omphalopagus.

“The names sound similar, but they’re very different,” Dr. Chmait says of the two conditions. “I have a beautiful picture, a textbook picture that I saved. I gave Aubree a copy of it. You can see the bridge connecting the two twins together.”

In some ways—and I emphasized this to Aubree—although it was a big shock that these were now conjoined twins, it was a better prognosis. Of course, in other ways it was terrifying."

Fetal-maternal specialist Ramen Chmait, MD

Though the new finding overwhelmed Aubree, Dr. Chmait saw plenty of good in it, as omphaloceles carry a high risk of a genetic abnormality, while omphalopagus does not. “Omphaloceles can impart severe neurological impairment,” he says, “versus conjoined twins that will need multiple surgeries, but their brains are likely not impacted.

“In some ways—and I emphasized this to Aubree—although it was a big shock that these were now conjoined twins, it was a better prognosis. Of course, in other ways it was terrifying.”

A hunch that she was having twins

Even though this was her first pregnancy, Aubree sensed early on that it wasn’t ordinary. She felt bloated and nauseous to the extreme. “My friend who was also pregnant was having symptoms, but mine were so much more intense,” she says. “I just had a feeling that I was pregnant with twins.”

Oddly, this wasn’t Aubree’s first premonition that she would have twins.

“I would play in my room as a kid, and I would make up these little families and I would always have twins. My whole life I always said, ‘I’m going to have twins, I’m going to have twins.’”

Perhaps she manifested them, as in the eighth week of her pregnancy she and her husband, Jack, got their first glimpse of what thereafter, until birth, would be called Baby A and Baby B.

“I was lying there and the tech turned the screen and there were two little babies there, really close together,” Aubree says. “The chaos started right then.”

Conjoined twins were never part of her childhood imaginings. She and her husband “went ghost white,” she says, when Dr. Chmait gave them the news. “I said, ‘OK,’ and we walked out. I didn’t know how to process it at that time.”

A return visit to Dr. Miller and Nurse Care Manager Irene Klecha, MSN, RN, helped put Aubree and Jack more at ease. Dr. Miller shared Dr. Chmait’s view that conjoined twins was the better outcome, since it was unlikely to produce any neurodevelopmental disorders. “We were counseling them that this looked like the best-case scenario,” he says.

The newborns are separated

Olivia and Lainey—Baby A and Baby B, respectively—were born June 3, 2024, and a day later were surgically separated by CHLA pediatric surgeon Aimee Kim, MD, with the assistance of Christopher Gayer, MD, PhD, FACS, FAAP, Chief of Pediatric Surgery, and a host of support from two teams—one for each twin.

“We had two fantastic anesthesia teams, scrub techs, and nurses,” Dr. Kim says. “That's what made this work.”

Same as her colleagues, the surgery was a first for Dr. Kim—and she doesn’t expect there to be another.

“This is not a case that anyone sees more than once in a lifetime,” she says, noting that Olivia and Lainey were categorized as a variant called “minimally conjoined,” so as to distinguish their attachment at the intestines from what people typically imagine when they think of conjoined twins. “This was something very different.”

Prenatal scans offered Dr. Kim an idea of what the twins’ anatomy looked like, but left a few surprises for her and Dr. Gayer to discover after Olivia and Lainey were born. They found multiple defects, including abnormalities with the twins’ urinary and digestive systems.

The long-term surgical solutions for the twins’ anatomical issues are still to be addressed, Dr. Kim says, in consultation with Aubree and Jack and CHLA’s Complex Reconstructive Urology Surgery team. That will require more imaging as the twins near their first birthday. When they were neonates, their organs were too underdeveloped to make any determinations.

For now, all things considered, Dr. Kim says Olivia and Lainey are thriving. “They’re eating. They’re drinking. They’re developmentally normal babies doing normal baby things. They’re spunky, happy, healthy girls.”

Their mother says so, too, though noting that their personalities diverged from day one. “Lainey came out feisty and sassy, and Olivia came out calm and quiet and sweet,” Aubree says. “They’re still like that about a year later.”

She mentions that she never saw Olivia and Lainey conjoined. Her first glimpse of her daughters came after the separation surgery, when they were in intensive care. Still recovering from a C-section, Aubree couldn’t sit up to see them and had to rely on a nurse’s description.

“They were facing each other, and the nurse said, ‘They have light hair and they’re so beautiful!’” Soon after, she would see for herself. “They really are.”