Five-inch needle to pierce the womb // A four-millimeter balloon to open a fused valve // A wire the width of a human hair to position the balloon // All of which make one wonder: Is it...
Too Soon for Surgery?
Jennifer and Douglas Rose knew they were expecting twins, but a routine ultrasound at 20 weeks of gestation showed the girls, who shared a placenta, weren’t developing properly. Some blood vessels that joined the placenta were abnormal, resulting in a disproportionate circulation of blood to the fetuses. One was surrounded by an overly large amniotic sac, and the other’s sac was too small. What’s worse, the fact that the condition, known as twin-twin transfusion syndrome, or TTTS, was visible so early in the pregnancy meant it was especially acute. Untreated, one baby would receive too much blood, become hypertensive, urinate excessively and produce an overabundance of amniotic fluid. The other twin would suffer from low blood pressure, a deficit of oxygenated blood, kidneys that don’t produce urine and stunted growth. Both babies would likely die of heart failure.
The conventional therapy for TTTS, amnioreduction, uses a needle to remove as much as three liters of amniotic fluid from around the twin with too much blood and in some cases may prevent the condition from progressing, though it can’t reverse its effects. But that approach would have had little effect in this severe case, and within days of her ultrasound on Sept. 25, 2006, Jennifer Rose, 38, was at the Children’s Hospital of Philadelphia to be evaluated for an alternative treatment. Mark Johnson, the hospital’s director of obstetrics for the Center for Fetal Diagnosis and Treatment, performed a procedure, selective laser ablation, on the abnormal vessels connecting the twins. “A huge system of blood vessels had expanded over the surface and within the placenta, much like the roots of a tree,” says Johnson. His plan was to insert a two-millimeter fetoscope equipped with a laser into Rose’s abdomen and map every vessel from its origin in the umbilical cord to the point at which it joined the placenta, then use the laser to close off any vessel that improperly connected the twins.
Rose decided to have the surgery, despite considerable risks to the fetuses. “We were told there was a 40% chance both babies would survive, and a 60% chance that one would,” she says. The anterior position of her placenta further complicated things, partially blocking Johnson’s view. But he managed to close off the problem blood vessels, and after a two-day hospital stay and 10 days of bed rest in Philadelphia, Rose went home to Waterbury, Conn., to await delivery. During further bed rest, she couldn’t pick up her infant twins, who had been born less than a year earlier. Frequent ultrasounds showed the developing fetuses and their amniotic sacs to be roughly the same size until 35 weeks into Rose’s pregnancy—just two weeks short of full term—when one baby suddenly gained weight and began producing too much amniotic fluid. Rose’s obstetrician induced labor a week later, and Rose vaginally delivered two healthy girls, 6 pounds 9 ounces, and 5 pounds 8 ounces, whom the parents named Faith and Grace. “Before this surgery existed, these babies would not have been born,” says Rose.
Of the approximately 100 fetal procedures done annually at the Children’s Hospital of Philadelphia, half are for TTTS, which has become increasingly prevalent because of the rising use of fertility drugs. The surgery is one of a half-dozen or so interventions that have been tried in any numbers since the 1980s, and it’s among the few that have proved clearly superior to the alternative of waiting until after birth and then operating only if necessary. Yet, while the idea of detecting and fixing problems before birth has long been appealing, and experiments have been under way for decades, just a handful of randomized clinical trials have even attempted to compare the two approaches. That’s partly because parents often refuse to participate for fear their fetus will be assigned to the control arm of a study and thus excluded from an intervention that could save or prolong the fetus’s life. And it’s not always clear which fetuses will benefit from in utero surgery, an uncertainty that may expose babies and their mothers to risks without potential rewards.