How long into pregnancy should one do the Tissue Screening for Chromosomal Abnormalities, what is the approximate cost, and is it necessary to have a 3D ultrasound?

Patient's question:

April 6th was the last menstrual period

Doctor's answer:

During the 3rd and 4th months of pregnancy, it is possible to determine whether it is a single or multiple pregnancy, as well as to assess the size and development of the fetus. The second time, around 6 and a half months, the position of the fetus, the amount of amniotic fluid, and whether there are any abnormalities can be checked. The third time, during the last 2-3 months of pregnancy, the fetal position, size, maturity of the placenta, and whether the umbilical cord is wrapped around the fetus can be assessed, and prenatal preparations should be made. B examinations should not be performed during the early stages of pregnancy, except in special cases where bleeding or other symptoms occur, in which case an examination may be necessary. It is best not to exceed 5 examinations.