The Nuchal Scan Test for Birth Defects

A nuchal translucency scan is one of the most minimally invasive procedures done during a pregnancy which may have the potential of pointing out a possible birth defect. It is part of the routine ultrasound exams that are done over the course of almost every pregnancy to ensure that things are progressing well.

Ultrasound technology has been deemed safe for the fetus and for the expectant mother, and since they are quick and easy to do, physicians have the freedom to do as many as necessary to monitor the progress of a pregnancy and also to set anxious parents at ease.

Generally speaking, a healthy, young mom-to-be can expect to have two ultrasounds taken over the course of the pregnancy: one at about 12 weeks to check fetal development and also to check for the nuchal translucency and another toward the end of the pregnancy or seven to eight months, to permit physicians to once again ensure that all is developing well, ascertain the birth weight of the child, and also to get a glimpse as the position the child is holding. Women who have suffered a miscarriage, are older than 35, or possibly may not be aware as to the date of conception can expect to undergo more frequent ultrasound examinations.

Nuchal Translucency

The nuchal scan is considered a routine exam and will be performed right around the 12th week of pregnancy. It is the first indicator of Down syndrome in an otherwise healthy fetus. Checked is the area referred to in clinical terms as nuchal translucency, which is located by the neck of the developing baby. Amounts of fluid checked in that vicinity may indicate a higher risk for birth defects which fluid levels falling into normal ranges do not necessarily rule out the possibility, but instead lower the potential for Downs.

It is important to recognize that an increase of fluid levels detected when using a nuchal scan to show potential for birth defects is not a conclusive marker of the actual presence, and any discussions with respect to pregnancy termination or preparations for bringing a disabled child into the world should be reserved until further testing is done.

Follow Up Testing

The follow up tests that can give better insight into the likelihood of the actual presence of a birth defects are an amniocentesis and also chorionic villus sampling; yet because these two tests carry with them the risks of harming the fetus or actually inducing a miscarriage, expectant mothers are usually reluctant to undergo the procedures unless medically deemed necessary. It is important to understand that the nuchal scan is only effective between the 11th and 13th week of pregnancy, thus a proper age determination of the fetus at the onset of pregnancy or as soon as possible thereafter is vital.

The nuchal translucency will generally cease to be a useful measuring tool after the 14th week of gestation since the fetus will have developed to such an extent that any excess fluid is being drained away, causing the nuchal scan to come back negative even in cases of confirmed Down syndrome.