The San Diego Perinatal Center's Nuchal Translucency Program offers first trimester screenings for fetal aneuploidy.

The current standard in California is to offer all pregnant women serum screening for fetal aneuploidy through the state-sponsored Expanded AFP Program. This screening test is based on risk calculations derived from maternal age and three maternal serum analytes (estriol, AFP, hCG). The test is supplemented by ultrasound evaluation for fetal anomalies and soft markers; ultrasound findings that are associated with Down Syndrome.

This screening is not offered to women until the second trimester (15–20 weeks gestation), a time when a woman’s pregnancy is more apparent and options are more limited. Several recent developments are poised to change the current standard.

Researchers have found that ultrasound measurement of the nuchal translucency—the swelling under the skin at the back of the fetal neck—in the late first trimester (11–14 weeks gestation) has a sensitivity that is comparable to second trimester maternal serum screening in detecting fetuses with Down Syndrome. Abnormal nuchal translucency measurements have also been associated with Trisomy 18, Trisomy 13, skeletal dysplasias and cardiac anomalies. Additional research has shown that combining this measurement with first trimester maternal serum (free beta hCG and PAPP-A) tests may further improve the sensitivity and specificity of first trimester screening. Patients with screen positive test results have the option of chorionic villus sampling as early as 11–12 weeks gestation.

The San Diego Perinatal Center is one of the first centers in Southern California—and the only center in San Diego—to earn a certification in nuchal translucency screening from the Fetal Medicine Foundation, an organization recognized internationally for setting nuchal translucency measurement standards.

Patients interested in first trimester screening can be referred for genetic counseling and nuchal translucency measurement as early as 11–12 weeks gestation. Ideally, patients should have dates confirmed by an earlier office crown rump length, as the nuchal translucency measurement cannot be made prior to 11 weeks gestation.

For more information, call (858) 939-6860.