The clinical standard for prenatal diagnosis of Down syndrome has been to offer maternal serum screening in the 15th to 16th weeks of gestation. However, a new clinical standard for detecting Down syndrome is becoming more widely used. The new standards include the use of first-trimester screening combined with the use of serum screening by associated plasma protein A (PAPP-A), human chorionic gonadotrophin (free beta-hCG) and ultrasound screening for nuchal translucency measurements .
Human chorionic gonadotrophin (free beta-hCG)
Free beta-hCG, a hormone that is important for regulating a healthy human pregnancy, is used in maternal serum screening because it can be detected in maternal plasma or urine by the 8th or 9th day after ovulation has started. Free beta-hCG levels can vary throughout pregnancy, reaching a peak level at about 8 to 10 weeks and declining there after. Approximately every two days, during the first four weeks of gestation, the free beta-hCG levels will increase and lower . During the 6th to 7th weeks of gestation, the levels of free beta-hCG can take up to three and a half days to double . Therefore, as the pregnancy progresses after the 12th week of gestation, the free beta-hCG hormone is not being produced as often . Elevated levels of free beta-hCG can help identify Down syndrome during pregnancies . Research is still being done to figure out the specific function of the free beta-hCG hormone.
Nuchal translucency screening test
The nuchal translucency screening test is a prenatal test that allows healthcare practitioners to asses the risk of a baby being born with Down syndrome. The measurement of the nuchal fold is an important indicator for the development of Down syndrome because there is a larger than normal build-up of fluid in the back of the neck. A thickness of between 2.5 to 4 mm, with 3 mm the most commonly used measurement, is used to asses if a fetus is at risk for Down syndrome .
The accuracy of the nuchal fold is very important for risk assessment. The factors can an affect the accuracy of the measurement for the nuchal fold includes: fetal position, and measurement technique .
Down Syndrome Prognosis
There is no cure for Down syndrome at this time. It is important to note that a lot of children that are born with Down syndrome live a full life, attend regular schools, attend regular classes, play in special olympic events, and much more.
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