BY YUI MIURA | ILLUSTRATION: FRANÇOIS LUKS, MD
Facing a rare pregnancy complication, one family put their faith in a Brown surgeon.
T he monitor beeped at a constant pace, sounding out her heartbeat. Morgan B. recited the names of her family members and loved ones to herself, uncertain whether she would wake up to see them again. In an operating room at Rhode Island Hospital, Morgan awaited surgery on the two babies in her uterus.
“ The odds were completely against us,” Morgan says, remembering that day.“ I was putting the lives of my future children, and my own, in the hands of complete strangers.” It was the most frightened she’ d ever been, she says.
Three days earlier, on a Friday the 13th in November 2020— 19 weeks into her pregnancy— Morgan’ s regular check-up had led to the most difficult conversation of her life. It was early in the COVID pandemic, and she was alone in Hasbro Children’ s Hospital at her ob / gyn appointment. The ultrasound of Morgan’ s twin girls had showed an anomaly: One of the twins( Baby A) had cardiac failure and the other( Baby B) had too much blood in her body.
Morgan’ s doctors suspected twin-to-twin transfusion syndrome( TTTS). In an ideal monochorionic( identical) twin pregnancy, each twin uses about half of the placenta and blood flow. While blood circulates from each fetus to its part of the placenta, some blood flows back and forth between the two fetuses. However, in 10 percent to 15 percent of cases, an imbalance arises in blood flow and placental share between the twins. One twin gives too much blood( the donor) to the other twin( the recipient). This is TTTS, and it is dangerous for both fetuses.
“ The donor can experience growth restriction for two reasons,” says TTTS expert François Luks, MD, chief pediatric surgeon at Hasbro Children’ s and the J. Murray Beardsley Professor of Surgery at The Warren Alpert Medical School of Brown University. The donor twin“ is spending way too much energy providing blood to the recipient,” he says, and“ its placental share may be too small.”
In severe TTTS, Luks adds, the donor twin may develop anemia and high-output heart failure due to chronic blood loss.“ It’ s transfusing blood to its twin. It’ s the same thing as if you were slowly bleeding out,” he says.
After the first trimester, amniotic fluid— contained in separate amniotic sacs for each twin— is composed mostly of fetal urine. When blood volume decreases in TTTS, the donor fetus’ s body will work to conserve fluid by decreasing urine production. As a result, the donor’ s bladder fills poorly, and amniotic fluid volume decreases, leading to a condition called oligohydramnios( low amniotic fluid) or anhydramnios( no amniotic fluid). The surrounding amniotic membrane tightly wraps around the fetus, making what is called a“ stuck twin.”
“ In contrast, if the recipient gets too much blood, it’ s pretty much the same as drinking gallons of water every day. What’ s going to happen? You’ re going to make more urine,” Luks says. The recipient twin receives excess blood, leading to increased urine production and polyhydramnios( excess amniotic fluid). This combination of low fluid around the donor and excessive fluid around the recipient, known as the poly-oli sequence, defines the TTTS diagnosis.
“ We need to intervene quickly,” Morgan remembers her doctor saying. But it was a weekend, when expert surgeons were often unavailable and operating room schedules were limited, with rooms reserved for dire emergency trauma cases. The hospital sent Morgan back to her home in Massachusetts with instructions to return on Monday.
SPRING 2026 l HEALTH DISCOVERIES @ BROWN 17