Programs and Services

First Trimester Screening

First trimester screening is designed to identify whether you may be at increased risk of having a baby with Down syndrome or trisomy 18. These conditions are types of chromosomal abnormalities. The screening involves a maternal blood test and an ultrasound measurement called “nuchal translucency.”

First trimester screening can be done between 11 and 13 weeks gestation (sooner than other screening tests), and results take about one week. First trimester screening must be performed by an ultrasonographer or physician who is certified in nuchal translucency measurement.

It’s important to remember that first trimester screening is an indicator, not a definitive answer, about a baby’s health or condition. Even with an “abnormal” screen, most of the time the baby is healthy. Likewise, not every baby with Down syndrome or trisomy 18 will be identified through first trimester screening. Once a first trimester screening is performed, additional tests can give a definite answer about these and other conditions, if desired Learn more about first trimester screening (PDF opens in new window).

Date: Dec. 15, 2006

Online Editor(s): Christopher Sadler