Practice Guideline Briefs

Am Fam Physician. 2004 Oct 15;70(8):1592-1594.

First-Trimester Screening for Genetic Defects

The Committee on Genetics of the American College of Obstetricians and Gynecologists (ACOG) has issued a new report entitled, “ACOG Committee Opinion No. 296: First-Trimester Screening for Fetal Aneuploidy.” The report appears in the July 2004 issue of Obstetrics and Gynecology.

According to the report, first-trimester screening for genetic defects is now an option for pregnant women, but only if certain criteria are met. New technologies, such as measuring nuchal translucency (NT), have allowed for earlier, noninvasive screening for chromosomal abnormalities and, when combined with serum screening in the first trimester, have detection rates comparable with standard second-trimester screening.

First-trimester screening offers several potential advantages over second-trimester screening. When test results are negative, it may help reduce maternal anxiety earlier. If results are positive, it allows women to take advantage of first-trimester prenatal diagnosis by chorionic villus sampling (CVS) at 10 to 12 weeks of gestation or second-trimester amniocentesis (15 weeks). Detecting problems earlier in the pregnancy may allow women to prepare for a child with health problems. It also provides women the option to terminate the pregnancy earlier, which is associated with reduced maternal morbidity.

During the past decade, research has shown an association between fetuses with certain chromosomal abnormalities and ultrasonographic findings of an abnormally increased NT (an area at the back of the fetal neck) between 10 and 14 weeks of gestation. The newer first-trimester screening method includes measurement of NT, free beta subunit of human chorionic gonadotropin (β-hCG), and pregnancy-associated plasma protein-A (PAPP-A). It has a detection rate for Down syndrome comparable with the more commonly used second-trimester screening using four serum markers (alpha-fetoprotein, β-hCG, unconjugated estriol, inhibin-A). Women who screen positive are at an increased risk for having a child with Down syndrome. These women may then decide to have a diagnostic test such as amniocentesis or CVS to determine if the fetus is affected because screening tests can give false-positive results.

First-trimester screening also can help detect other chromosomal abnormalities such as trisomy 18. In addition, measurement of NT may help detect pregnancies at risk for major heart defects in the fetus. However, first-trimester screening cannot be used as a screening test for spina bifida.

Sonographer training and ongoing quality assurance are essential if NT is used as a screening method. Because small differences in NT measurements can have a large impact on the risk prediction of Down syndrome, sonographers need to be monitored closely. ACOG does not recommend using the NT measurement by itself to screen for Down syndrome because it has a high positive screen rate when used without serum markers. Although first-trimester screening is an option for some women, it should only be offered if the following criteria are met:

• Appropriate ultrasound training and ongoing quality-monitoring programs are in place.

• There are sufficient information and resources to provide comprehensive counseling to women regarding the different screening options and limitations of these tests.

• Access to an appropriate diagnostic test is available when screening tests are positive.

CDC Report on Cancer Mortality Surveillance

The National Center for Chronic Disease Prevention and Health Promotion of the Centers for Disease Control and Prevention (CDC) has released a new report on cancer mortality entitled, “Cancer Mortality Surveillance—United States, 1990–2000.” The report is available online at http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5303a1.htm.

Cancer is the second leading cause of death in the United States and is expected to become the leading cause of death within the next decade. Considerable variation exists in cancer mortality between the sexes and among different racial/ethnic populations and geographic locations. The description of mortality data by state, gender, and race/ethnicity is essential for cancer-control researchers to target areas of need and develop programs that reduce the burden of cancer. It also can help clinicians in specific geographic areas develop programs in their communities to target high-risk populations.

Mortality data from the CDC from 1990 to 2000 were used to determine that mortality from cancer decreased among the majority of racial/ethnic populations and geographic locations in the United States. Statistically significant decreases in mortality among all races combined occurred with lung and bronchus cancer among men, colorectal cancer among men and women, prostate cancer, and female breast cancer.

Cancer mortality remained stable among American Indian/Alaska Native populations. Statistically significant increases in lung and bronchus cancer mortality occurred among women of all racial/ethnic backgrounds, except among Asian/Pacific Islanders.

Although cancer remains the second leading cause of death in the United States, the overall declining trend in cancer mortality demonstrates considerable progress in cancer prevention, early detection, and treatment. More effective tobacco-cessation programs are necessary to reduce lung and bronchus cancer mortality among women and sustain the decrease in lung and bronchus cancer mortality among men. Additional programs that deter smoking initiation among adolescents are essential to ensure future decreases in lung and bronchus cancer mortality. Continued research in primary prevention, screening methods, and therapeutics is needed to further reduce disparities and improve quality of life and survival among all populations.

School-Based Mental Health Services

The Committee on School Health of the American Academy of Pediatrics (AAP) has issued a new policy statement entitled, “School-Based Mental Health Services.” The statement appears in the June 2004 issue of Pediatrics and is available online at http://pediatrics.aappublications.org/cgi/reprint/113/6/1839.

Because up to 20 percent of children and adolescents have mental health problems, physicians must work closely with school-based programs to improve access to mental health resources, according to the AAP. During the past 20 years, the percentage of youth with psychosocial problems has grown from 7 to 19 percent. The AAP recommends that mental health programs be an integral part of a school’s environment, and that these programs work closely with a child’s primary care physician or “medical home” to ensure optimal care. Strict confidentiality is critical to maintaining a successful mental health program, except in instances when the safety of students, family members, or staff is threatened.


Copyright © 2004 by the American Academy of Family Physicians.
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