Down syndrome screening is a testing method that involves extracting serum from pregnant women, detecting the concentrations of alpha fetoprotein and chorionic gonadotropin in maternal serum, and calculating the risk factor of giving birth to a Down syndrome baby based on the pregnant woman's due date, age, weight, and gestational age at the time of blood collection. Does Down syndrome screening require holding urine on an empty stomach?
Before undergoing Down syndrome screening, it is necessary to have an empty stomach and not drink water, but there is no need to hold urine. During the 17th week of Tang screening, fasting is required because the relevant blood indicators tested during Tang screening are easily affected by diet. Eating and drinking water can easily affect the concentration of alpha fetoprotein, free HCG, and estriol, making Tang screening's calculation results inaccurate. So it is generally recommended to abstain from eating and drinking after 24:00 the night before doing Tang screening.
Tang screening is a comprehensive analysis based on the gestational age, height, and weight of pregnant women to determine whether the fetus has congenital genetic problems. This type of examination is conducted through blood sampling, not B-ultrasound examination, so there is no need to hold urine.
Down syndrome screening only checks the probability of fetal illness, not the diagnosis items, and the results only determine high-risk and low-risk. There are certain requirements for the gestational age of Down syndrome screening. Generally, early Down syndrome screening or mid-term Down syndrome screening should be conducted at 12 weeks and 16-20 weeks of pregnancy, respectively. This is based on the perspective of gestational age to determine the timing of Down syndrome screening.
