Birth Defect Screening Plan Outlined by State : Voluntary Program Offers Blood Tests to Detect Malformed Fetuses, Includes Advice for Mothers

The state of California, in an unprecedented genetic screening program to begin next month, will require all obstetricians and other prenatal-care providers to offer pregnant patients a blood test to detect serious birth defects in the fetus.

The prenatal care providers will be required to furnish each patient with a state-prepared brochure--available in several languages--that discusses birth defects and the merits of taking the blood test, which will be voluntary.

For the small percentage of women who are found to be carrying severely malformed fetuses, the booklet cites the availability of abortion or special medical care if a woman wishes to continue her pregnancy.

All expectant mothers will be asked to sign a statement either agreeing or refusing to take the blood test.

The statewide program is the first of its kind in the country and was developed over the last three years in response to a legislative mandate.

Genetic screening programs often raise social and political controversy because implicit in them is the choice of aborting malformed fetuses.

There is also scientific controversy because the blood test, which involves a fetal substance called alpha fetoprotein, is not always accurate. Some medical practitioners fear that women who test positive will abort what actually is a normal, healthy fetus. The brochure deals with this shortcoming by recommending further testing whenever the blood test shows a possible birth defect.

“This program won’t add a significant number of new pregnancy terminations,” said Dr. George C. Cunningham, chief of the genetic disease branch of the state Department of Health Services. “Without it, many more terminations would be done prematurely on the basis of incomplete and inaccurate testing.”

The program was officially announced this week in letters to 3,500 obstetricians, family physicians and nurse-midwives throughout the state who care for about 450,000 pregnant California women annually.

The initial blood test will be offered to all pregnant women seen before 20 completed weeks of pregnancy.

The test will screen for serious neural tube defects, including an incomplete brain or skull called anencephaly and an opening in the bones of the spine called spina bifida, as well as some other birth defects.

Researchers expect the program to identify about 80% of neural tube defects, which occur in one in 1,000 live births in the state, Cunningham said.

A Range of Defects

Anencephaly is always fatal before or very soon after birth. Spina bifida is associated with a range of mild to severe mental and physical defects, including mental retardation, leg paralysis and lack of bowel and bladder control. Medical costs can exceed $80,000 in the first year of life. Life expectancy for spina bifida patients ranges from less than a year to close to a normal life span.

“These are very tragic problems for the mother and the family, and to avert them is important,” said Dr. Joan Hodgman, director of the newborn program at County-USC Medical Center.

Most genetic screening currently is done for families with a history of birth defects, or when the pregnant woman is over age 35 and thus at higher risk for chromosomal abnormalities such as Down’s syndrome. But nine out of ten neural tube defects occur in families without such a prior history; therefore it is necessary to screen widely to detect such abnormalities.

Cunningham expects that about 95% of women screened will test negative and be reassured. Of the 5% initially testing positive, only one in 50 will probably be found to carry a severely malformed fetus after further evaluation.

Possibility of Error

Additional diagnostic tests are necessary because the initial blood test is not specific for the birth defects and therefore often can be in error.

The specialized follow-up tests include ultrasound, in which sound waves are used to make a picture of the fetus on a television screen, and amniocentesis, in which a small amount of fluid from around the fetus is extracted and analyzed.

The state estimates that if 50% of pregnant women participate in the screening and 90% of those with a severely malformed child choose an abortion, 200 abortions may result. About 120,000 abortions are performed in California each year.

“The overwhelming positive effects of the program should be highlighted,” said Dr. Lawrence Platt, director of the fetal care program at County-USC Medical Center. “It is clearly directed not at how many more babies we can terminate, but at how we can improve the perinatal outcome when birth defects are present.”

Best Time for Tests

Alpha fetoprotein screening must begin between weeks 15 and 20 of pregnancy, but is best done between weeks 16 and 18. Cunningham said that results of the initial blood test would be available within several days. Additional diagnostic testing, if necessary, could take three to four weeks, but would be expedited for women entering the program late.

The program is designed to get answers by the 24th week of pregnancy, an outer time limit for abortions except when the mother’s life is threatened, according to County-USC’s Platt.

The program is meant to be self-financing. The initial blood test costs $40, which will be covered by Medi-Cal and some medical insurers and prepaid health plans, Cunningham said. The fee also would cover additional diagnostic and laboratory tests for women who need them, if they go to a state-approved screening laboratory or prenatal diagnostic center. These services might cost up to $1,000 otherwise. Abortions or other costs of pregnancy care are not covered.