FIRST TRIMESTER PRENATAL SCREENING

between the 11th and 14th week of pregnancy

 

Risque-du-syndrome-de-Down-To screen for trisomy 21, 18 and 13, for other fetal abnormalities and for adverse events in pregnancy, you can have access to a top quality first trimester prenatal screening at FERTILYS. This involves a fetal ultrasound between the 11th and 14th week and a test to measure proteins in the maternal blood.

This prenatal screening program, which is safe for the fetus, is available to all pregnant women, regardless of age. By participating in this program, women aged 35 and over can often avoid an invasive diagnostic test, such as amniocentesis. Women under 35 may consider a diagnostic test if this screening indicates a high risk. For women with an intermediate risk (1:100 – 1:1000), a high quality test detecting fetal DNA circulating freely in maternal blood is also available at FERTILYS.

During the ultrasound, the fetus is generally visualized through the abdomen. Occasionally, the view is not that clear, and a transvaginal ultrasound may be required.

 

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DETERMINING RISK

Nuchal translucency is a thickening at the back of the neck observed in all fetuses between the 11th and 14th week (a black space corresponding to fluid accumulation in the soft tissue of the neck – see photo). Data based on over 200,000 pregnancies clearly show that the thicker the nuchal translucency, the greater the risk of the fetus having a chromosomal abnormality.

dopplerIn recent years, other fetal ultrasound markers, besides nuchal translucency, have been added and continue to be added to better identify the risk of carrying a fetus with Down syndrome. For instance, there is an increased risk of trisomy 21 in fetuses with absent nasal bone ossification, an increased frontomaxillary facial angle, significant triscupid valve regurgitation in the heart and reverse blood flow in the ductus venosus (continuation of the umbilical vein through the liver). Although these markers are not regularly used, they can sometimes be very useful in certain clinical situations.

Nuchal translucency measurement combined with maternal age only detects about 70% of fetuses with Down syndrome. Several of the world’s leading experts have made it clear that prenatal screening tests should never be based solely on nuchal translucency measurement, or solely on genetic biochemistry.

Having an additional maternal blood test the day of the ultrasound, which measures two proteins—pregnancy-associated plasma protein A (PAPP-A) and the free beta human chorionic gonadotropin (beta hCG), increases the detection rate for trisomy 21 to 96% with a false positive rate of only 2.5%.

 

IMPORTANT

As part of our prenatal screening program, FERTILYS has chosen to always offer the optimal screening test, which combines biochemistry and ultrasound in a single visit in the first trimester.

If you have continued concerns, you may feel the need for a more definitive answer. When the identified risk is more than 1 in 100, we generally offer an invasive diagnostic test, such as amniocentesis. The advantage is that it gives a more definitive answer—a diagnosis. The disadvantage is that it causes miscarriage in 1% of cases. Another diagnostic test, CVS (sample of placental cells is taken using needle aspiration), can sometimes replace amniocentesis. The advantage is that it can be performed earlier—from the 11th week. The risk of fetal loss associated with CVS is the same as amniocentesis.

For women with an intermediate risk (1:100 – 1:1000), a high quality test detecting fetal DNA circulating freely in maternal blood is always available at FERTILYS.

 

WHAT ELSE DIFFERENTIATES FERTILYS?

Unlike many other centers, prenatal screening performed at FERTILYS in the first trimester screening is not only limited to screening for trisomy 21, 18 and 13. It also allows the detection and prevention of adverse events in pregnancy such as preeclampsia, intrauterine growth retardation and preterm labor.

 

Although the first trimester fetal ultrasound identifies certain serious physical defects, others cannot be detected. We therefore always recommend pregnant women to have a detailed ultrasound in the second trimester at around the 18th to 22nd week. This provides an additional non-invasive alternative to detect more precisely some structural fetal anomalies such as open neural tube defects (spina bifida), limb defects, heart malformation, etc., before considering genetic counselling and more invasive diagnostic tests.

 

You’re finally PREGNANT and need reassurance? Get immediate PROFESSIONAL CARE at FERTILYS
FERTILYS Fertility Centre – Fertility, IVF, Prenatal Screening