Early Down’s syndrome screening is 11-14 weeks, and you cannot be tested beyond 14 weeks. Normally, if you have irregular menstruation, you should calculate the gestational week based on the first ultrasound. Early Down’s syndrome screening is a preliminary screening, the accuracy rate is not high, if there are abnormalities need to be comprehensive analysis, if necessary in the middle of pregnancy to do Down’s syndrome screening and amniocentesis, can be a clear diagnosis. In the early stages of pregnancy, it is advisable to have an abortion, because once a large fetal malformation occurs, it will affect the whole family, usually strengthen maternity checks and regular prenatal checkups. Try to stay away from radiation, viruses, etc., and keep your mood relaxed in the early stages of pregnancy. Early pregnancy without special circumstances is not recommended to blindly keep the fetus, so as not to miss nature’s superior and inferior screening.