Fetal repair: safe for mom, chancy for child.

Fetal repair: Safe for mom, chancy for child

A bold new surgical approach to repair fetal defects in the womb poses no undue hazard for mothers, say researchers who have performed the operation since 1981. However, the experimental procedure remains a risky gambit for the tiny fetus.

Michael R. Harrison, a pediatric surgeon at the University of California, San Francisco, pioneered the technique to correct several fetal flaws, including diaphragmatic hernia. This defect -- resulting from a hole in the muscular wall, or diaphragm, separating the chest cavity from the abdomen -- allows the fetal intestines to protrude into the chest, where they prevent normal lung development. Although surgeons can sew the diaphragm together after birth, the underdeveloped lungs cause breathing difficulties that often kill the newborn.

To give these babies a better shot at survival, Harrison operates before birth, usually during the second trimester. With the mother under general anesthesia (which reaches the fetus as well), he cuts through the mother's abdominal wall, lifts the arm of the fetus and makes an incision in the fetus' chest. He then tucks the fetal intestines back into the abdomen and sews a patch over the diaphragm hole, creating space for the lungs to develop normally.

However, the invasive procedure threatens the fetus with a risk of premature labor, since it can trigger uterine contractions even when mothers take drugs to prevent the complication. Babies born too soon risk death due to underdeveloped organs.

While Harrison and his co-workers have yet to solve the problem, they have now demonstrated that -- at least in their hands -- the procedure does not jeopardize the life of the mother. In the Feb. 13 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION, they report no maternal deaths or serious maternal injuries in their first 17 fetal operations, performed between 1981 and 1989. All cases involved severe fetal defects, which, if left untreated, were likely to kill the infants soon after birth.

The procedure, while offering hope for fetal survival, remains tricky. In three cases, the team couldn't repair the fetal defect and performed abortions in accordance with the mothers' prior requests. While the remaining 14 operations went smoothly, all of these mothers went on to deliver prematurely. The 14 fetuses made it through the operation, but only "some" survived beyond the preterm delivery, Harrison told SCIENCE NEWS. He declined to specify the number of survivors but acknowledged that the rate needs improvement.

Among the mothers, the operation had "no detectable effect on future fertility," the team reports. Eight women subsequently experienced normal pregnancies the researchers say they couldn't assess the fertility of the others.

Whether the surgery effectively treats fetal flaws remains an unanswered question, notes Howard C. Filston, a pediatric surgeon at the University of Tennessee Medical Center in Knoxville. Harrison plans to address that concern in a second trial, comparing the outcome of the fetal procedure with that of conventional neo-natal surgery.