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Extreme Measures

To move beyond the experimental realm, fetal procedures must be tested with randomized controlled trials. Here’s where the procedures stand.

By Anita Slomski // Spring 2008
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DEFECT

INTERVENTION

STATE OF RESEARCH

Myelomeningocele (spina bifida):

Protrusion of spinal membranes and cord through hole in vertebrae. Can cause paraplegia, incontinence and cognitive impairment.

Procedure involves opening the uterus to close the defect along the fetus’s spine at 20 to 26 weeks’ gestation (conventional treatment closes the defect after birth).

The NIH randomized Management of Myelomeningocele Study, now recruiting, will compare fetal surgery with postnatal repair and study the long-term effects on mothers.

Congenital diaphragmatic hernia:

Protrusion of abdominal organs into the chest cavity through a hole in the diaphragm, compressing the lungs and preventing them from developing fully.

Endoscopic insertion of a metal clip or a balloon to block off the fetus’s trachea, allowing secretions to accumulate and thus expand the lungs. The object is inserted at 26 to 28 weeks’ gestation and removed at 32 to 34 weeks.

NIH trial of endoscopic repair (results published in 2003) found no higher survival rates than for those who received postnatal care. Few U.S. surgeons perform the procedure; an improved technique is under study in Belgium.

Hypoplastic left heart syndrome:

An underdeveloped and nonfunctioning left ventricle and aortic valve, resulting in death or severe heart problems.

Ultrasound-guided insertion of a balloon at 22 to 24 weeks to open the aortic valve so the ventricle can develop.

Most are performed at Children’s Hospital Boston—about 75 to date. NIH turned down a proposal for a randomized controlled trial, deeming the technique too experimental.

Twin-twin transfusion syndrome:

Abnormal blood vessel connections between identical twins sharing a single placenta result in one fetus having too much blood flow and the other having too little.

Endoscopic laser ablation at 19 to 24 weeks to seal off the faulty blood vessel connections.

Results of the Eurofetus trial published in 2004 found that 48% of fetuses that underwent laser treatment were alive and well six months after birth compared with 26% that had amnioreduction, the standard treatment.

Diseases now treated postpartum with bone marrow transplants, such as sickle cell anemia and thalassemia. Transplants can lead to rejection and side effects from immunosuppressants.

Fetal stem cell transplants and gene therapy administered by needle into the amniotic fluid.

Under study in animals. The prediction: In five years, a stem cell transplant will be carried out in a human fetus to cure sickle cell anemia.

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Too Soon for Surgery?

Fetal surgery

Operating in the womb sometimes has miraculous results. Yet many still question whether it should be done at all.

What About Mom?

During fetal surgery, the child is not the only patient at risk.

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