Fall 2004

Fetal Cardiac Imaging Finding Faults in Fetal Hearts

More than 90 percent of major structural heart defects can be detected in the fetus via ultrasound screening. Currently, however, physicians who do routine prenatal screening find less than 20 percent to 25 percent of these defects. "That means that basic fetal ultrasound screening is not sufficient," says Dr. Lisa Hornberger, director of the Fetal Cardiovascular Program at UCSF Benioff Children's Hospital. "One percent of babies have a heart defect -- and 20 to 30 percent of these babies have a serious heart defect -- which means we are missing a lot of heart defects during the screening ultrasound given to the majority of pregnant women."

Hornberger is working to improve ultrasound screening to increase the detection of fetal heart defects. To accomplish this, she is building on her experience from the Hospital for Sick Children in Toronto, where she helped raise prenatal detection rates for major cardiac defects five-fold, from an original 6 percent to 12 percent, to 45 percent. For the detection of four-chamber view pathology -- hypoplastic left heart syndrome in particular -- detection rate climbed to about 80 percent.

"Improving the detection of most major structural heart defects is extremely important because we know that prenatal detection improves perinatal and neonatal outcome, and it's obviously critical for preparing families who are going to have an affected baby," Hornberger says.

"The other side of the coin is that being able to screen and eliminate the possibility of pathology is also important for families at risk for having a baby with a heart defect," she says. "It provides reassurance."

With the right training and the proper technology, Hornberger says practitioners can screen fetuses at 16 to 20 weeks. She also is working to develop techniques for reliably detecting cardiac defects in the fetus as early as 10 to 14 weeks, work that she has been involved in since 1992. One of the characteristics the obstetricians and radiologists may currently look for at this early gestational age is nuchal (at the neck) thickening, caused by an abnormal accumulation of water.

It has long been known that nuchal thickening can be one indicator of Down's syndrome, Hornberger says, but researchers also now know that nuchal thickening is associated with cardiac defects even in the absence of chromosomal defects like those that cause Down's syndrome. In fact, when tests show that a fetus has nuchal thickening but no chromosomal defects, there is still an 8 percent to 12 percent risk that the fetus has cardiac defects. The risks for other syndromes may also be higher in these circumstances.

Soon, early detection may become even more important, as physicians refine methods to treat these disorders while the fetus is still in the womb. When particular cardiac defects are detected early enough, it is possible that they may be repaired through interventional catheterization.

"There are obvious benefits to treating a fetus for certain congenital conditions rather than waiting until after a baby is born," Hornberger says. "Many cardiac disorders are progressive and evolve beyond the embryonic period. Early recognition and timely intervention may prevent some of the more severe secondary abnormalities that evolve as a consequence of a simple lesion. This secondary pathology may lead to the loss of the fetus or newborn or a worse long-term prognosis after birth." Operating on a fetus offers another benefit. In the womb, a fetus is already hooked up to an efficient life-support system. Circulating hormones and peptides also promote rapid healing where incisions are made.

In addition to her research in areas of fetal cardiac development, diagnosis and intervention, Hornberger is working to improve screening around the state. She and her UCSF colleagues offer courses in prenatal ultrasound screening.

Fetal Cardiovascular Program (415) 353-1887

The Fetal Cardiovascular Program at UCSF Benioff Children's Hospital assesses and manages fetal and pediatric heart disease. We have access to the latest technology for sophisticated imaging as early as the late first trimester. The program is a joint service of the UCSF Pediatric Heart Center and the UCSF Fetal Treatment Center.

Related Information

News Releases

UCSF Medical Center Moves Up to No. 6 in Nation
In pediatric care, UCSF Benioff Children's Hospital is No. 11, making it the highest-ranked pediatric center in California, according to the "America's Best Hospitals" ranking by U.S. News & World Report. This year, UCSF Medical Center moved up a spot to tie at sixth.

UCSF to Benefit from Children's Hospital Bond Measure
UC officials are heartened by voter approval of Proposition 61, the children's hospital bond measure, that authorizes $750 million in general obligation bonds for grants to children's hospitals. Each of the five UC children's hospitals are eligible for $30 million, which adds up to 20 percent of total funding from the proposition.

Institute of Medicine Elects Six
UCSF Faculty

Dr. Philip D. Darney, an obstetrician and gynecologist, and Nancy S. Padian, director of international research for the AIDS Research Institute and associate director of research for Global Health Sciences -- both professors of obstetrics, gynecology and reproductive sciences at UCSF -- were elected in October to the Institute of Medicine, along with four UCSF colleagues.