CVS was performed for the first time in
Milan by Italian biologist
Giuseppe Simoni, scientific director of
Biocell Center, in 1983.[4]
Use as early as eight weeks in special circumstances has been described.[5] It can be performed in a transcervical or transabdominal manner.[2] Although this procedure is mostly associated with testing for
Down syndrome, overall, CVS can detect more than 200 disorders.[6]
Advanced maternal age (maternal age above 35). AMA is associated with increase risk of
Down's syndrome and at age 35, risk is 1:400.[citation needed] Screening tests are usually carried out first before deciding if CVS should be done.
Risks
The risk of miscarriage in CVS is estimated to be potentially as high as 1–2%. However some recent research has suggested that only a very small number of miscarriages that occur after CVS are a direct result of the procedure.[7] Apart from a risk of miscarriage, there is a risk of infection and
amniotic fluid leakage. The resulting amniotic fluid leak can develop into a condition known as
oligohydramnios, which is low amniotic fluid level. If the resulting oligohydramnios is not treated and the amniotic fluid continues to leak it can result in the baby developing hypoplastic lungs (underdeveloped lungs).[8][9]
Additionally, there is also mild risk of limb reduction defects associated with CVS, with the risk being higher the earlier the procedure is carried.[10]
It is important after having CVS that the
obstetrician follows the patient closely to ensure the patient does not develop infection.
Chorionic villi and stem cells
Recent studies have discovered that chorionic villi can be a rich source of fetal stem cells, multipotent
mesenchymal stem cells.[11][12][13]
A potential benefit of using fetal stem cells over those obtained from embryos is that they side-step
ethical concerns among anti-abortion activists by obtaining pluripotent lines of undifferentiated cells without harm to a fetus or destruction of an embryo. These stem cells would also, if used to treat the same individual they came from, sidestep the donor/recipient issue which has so far stymied all attempts to use donor-derived stem cells in therapies.[citation needed]
Artificial heart valves, working tracheas, as well as muscle, fat, bone, heart, neural and liver cells have all been engineered through use of fetal stem cells.[14]
The first fetal stem cells bank in US is active in Boston, Massachusetts.[15][16][17][18]
Limitations
A small percentage (1-2%) of pregnancies have
confined placental mosaicism, where some but not all of the
placental cells tested in the CVS are abnormal, even though the pregnancy is unaffected.[19] Cells from the mother can be mixed with the
placental cells obtained from the CVS procedure. Occasionally if these maternal cells are not completely separated from the
placental sample, this can lead to discrepancies with the results. This phenomenon is called Maternal Cell Contamination (MCC).[19] CVS cannot detect all birth defects. It is used for testing
chromosomal abnormalities or other specific
genetic disorders only if there is family history or other reason to test.[citation needed]
^Wapner, Ronald J.; Evans, Mark I.; Davis, George; Weinblatt, Vivian; Moyer, Sue; Krivchenia, Eric L.; Jackson, Laird G. (2002). "Procedural risks versus theology: Chorionic villus sampling for Orthodox Jews at less than 8 weeks' gestation". American Journal of Obstetrics and Gynecology. 186 (6): 1133–6.
doi:
10.1067/mob.2002.122983.
PMID12066086.