Our Services

Combined first trimester screening

First trimester combined screening for Down syndrome is a new approach for early detection of Down syndrome and other genetic abnormalities in your fetus. This test is a screening test which provides individualized information about your baby’s risk of Down syndrome by combining your age, results of a blood test, and ultrasound measurement of the neck region (nuchal translucency) of your fetus. If the test indicates your baby is at increased risk for Down syndrome, you can decide to undergo a diagnostic test such as chorionic villus sampling (CVS) or amniocentesis.

How is combined testing performed?

As mentioned above, the three components of first trimester combined testing are maternal age, a blood test, and a nuchal translucency measurement of your fetus. The blood test can be performed as early as 9 weeks of pregnancy until 13 weeks 6 days of pregnancy. The blood can be collected by you at home (with a simple finger prick) and sent in to the lab or your blood can be collected at our office. The ultrasound examination is performed between 11 weeks 1 day and 13 weeks 6 days of pregnancy.

How will I get my results?

If your blood test is done more than a week before your ultrasound examination you will be given your test results at the time of your ultrasound. Your blood test may also be performed on the same day as your ultrasound. Your results will then be called to you in about a week.

Can my ultrasound be performed in my doctor’s office?

No, your ultrasound must be performed in our office. Our doctors and ultrasound technicians have received special training to perform this test and utilize high resolution ultrasound machines. In addition, our center participates in an on-going quality control program sponsored by the Society of Maternal Fetal Medicine.

What if my test indicates an increased risk of Down syndrome or other abnormalities?

Do not panic! In most cases your baby will not have Down syndrome. You will be offered genetic counseling to explain your test results and your options for further testing. These might include chorionic villus sampling at 10 to 12 weeks 6days of pregnancy or amniocentesis at 15 to 20 weeks of pregnancy.

Will this test identify all cases of Down syndrome?

No. This is a screening test and will identify approximately 90% of cases of Down syndrome. This means that approximately 10% of cases will be missed.

What other birth defects are detected by combined screening?

Combined screening also detects about 90% of cases of trisomy 18 and 13. These conditions are much more severe than Down syndrome. Most infants born with these disorders die shortly after birth.

Are cases of spina bifida detected by combined screening?

No, combined screening does not detect spina bifida. We recommend a blood test at 15 to 20 weeks of pregnancy or a detailed ultrasound at 18 to 20 weeks of pregnancy to screen for spina bifida.

Can this testing be performed on twins?

Yes, although the detection rate for Down syndrome is slightly lower.

What if I have questions?

Please call our office with any questions or to schedule an appointment, 415-202-1200. We will mail you our blood drawing kit as soon as you schedule your ultrasound appointment.