A40-year-old multigravida's pregnancy is confirmed at 8 weeks' gestation. she says, "i can't wait another 2 months for an amniocentesis to find out whether my baby has a chromosomal anomaly like my first child." the nurse responds that she can have chorionic villus sampling (cvs) between the tenth and twelfth weeks; what is true about this test if it is performed before this time?

There are high risk of following abnormalities or mis- happening if chorionic villus sampling (CVS)  are performed before 10th week of pregnancy:

a)Fetal defects

b)Miscarraige

c)  Fetal anomalies.

d)Risk of infection

As per the standard recommended by American Congress of Obstetricians and Gynecologists, the standard time to perform this test is between 10th & 12th week as at that time the chances of risk to fetus is very negligible. In no case CVs shall be conducted before 9th week of gestation.  

It is estimated that there is a risk of 0.5 to 1 % of miscarriage after CVs which usually happens within the 3rd day of test.  

small, big, or no change could occur in the phenotype. it could cause something as simple as a cats ears to curl backwards or something as frighting as death. it could also occur in the protien-coding area and have an effect on that but no effect on the amino acids. what has to occur is a changing in the hox gene or the control gene.