Pregnant women over 35 face a dilemma if they opt for prenatal genetic testing. If they decide to go for an amniocentesis or chorionic villus sampling to see if their fetus has any chromosomal abnormalities, they risk having a miscarriage.

But a new screening test available in B.C. eliminates that risk.

Known as first-trimester screening, the exam involves the use of high-resolution ultrasound BPU60 to measure nuchal translucency, a transparent space behind the fetus's neck that's temporarily visible late in the first trimester. A widening of this space is linked to an increased risk of chromosomal abnormalities. (It disappears by the time women go for their routine ultrasound in the second trimester.) FTS also detects the fetal nasal bone, the absence of which can indicate Down syndrome.

As its name implies, FTS is a screening tool, not a diagnostic measure. If FTS comes back positive for genetic abnormalities, women can then choose to have an amnio or CVS to confirm a diagnosis. But if it comes back negative, expectant moms can avoid going through such invasive procedures–and enduring the anxiety that accompanies waiting as long as two weeks for the test results.

Every doctor and pregnant woman wants to avoid an invasive test, another advantage of FTS, is that it's conducted between 11 and 14 weeks of pregnancy, while an amnio doesn't take place until between weeks 15 and 20. Including blood work that determines levels of pregnancy-associated plasma protein A (PAPP-A)–low amounts of which are associated with Down syndrome–FTS has a detection rate of 90 to 95 percent, with a five-percent false-positive rate.

"Pregnant women want to know earlier," Dr.Luo said. "A lot of couples don't want to tell anyone they're pregnant until they get test results. By 19 weeks, it's obvious you're pregnant." "An early-pregnancy ultrasound” can make the pregnancy feel more real," Dr.Luo says. "