A study comparing transcervical with transabdominal chorionic villus sampling (CVS)

Summary. Chorionic villus sampling (CVS) was performed in 50 anaesthetized patients before therapeutic abortion by the transabdominal route and then by the transcervical route. The two methods of villus sampling were equally successful in obtaining villi but the transcervical method was significantly better at obtaining chorionic villi >10 mg in weight (x² 13·92 P <0·001). Placental position did not affect villus recovery with either sampling method.     

A study comparing transcervical with transabdominal chorionic villus sampling (CVS)

Chorionic villus sampling (CVS) was performed in 50 anaesthetized patients before therapeutic abortion by the transabdominal route and then by the transcervical route. The two methods of villus sampling were equally successful in obtaining villi but the transcervical method was significantly better at obtaining chorionic villi greater than 10 mg in weight (chi 2 13.92 P less than 0.001). Placental position did not affect villus recovery with either sampling method.     

Chorionic villus sampling (CVS) and fluorescence in situ hybridization (FISH) for a rapid first-trimester prenatal diagnosis

OBJECTIVES: Early diagnosis of unbalanced chromosomal abnormalities can be crucial in minimizing the trauma caused by an elective abortion. Chorionic villus sampling (CVS) can be performed from 9 weeks of gestation. However, two major problems are encountered in fetal karyotyping using cultured cells from chorionic villi: the relatively slow growth of these cells in culture, which delays the diagnosis, and the occurrence of maternal cell contamination (MCC). With FISH, a result can be obtained within 24 h, and, as no cell culturing is involved, the problem of MCC is minimized. METHODS: Thirty-two women undergoing CVS between 9 and 12 weeks of gestation were offered FISH analysis in addition to the standard chromosome analysis. RESULTS: FISH was informative in all of the cases tested. Eleven aneuploidies were detected in cases of hygroma or abnormal nuchal translucency and two out of four fetuses from parental translocation were unbalanced. The decision to perform early termination of these chromosomally abnormal pregnancies was based on FISH results and ultrasound abnormalities, without waiting for karyotype results. CONCLUSION: The present study confirms that the association of FISH and CVS allows a rapid and early prenatal diagnosis, and emphasizes that this association is of great benefit in cases of known parental balanced translocation or when hygroma is detected by ultrasonography.     

Transcervical (TC) and transabdominal (TA) CVS for prenatal diagnosis in Rotterdam: experience with 3611 cases.

Data from 3611 consecutive CVS (TC, N = 1780; TA, N = 1831) were analysed with emphasis put on influence of maternal and gestational age at CVS on the fetal loss rate less than 28 weeks. For TC-CVS the gestational age varied from 9.3-11.6 weeks, for TA-CVS from 9.3-20 weeks. Sampling efficacy at first attempt was 86.5 per cent and 95 per cent respectively. In 4.6 per cent an abnormal result was established. In older mothers (N = 2362) the fetal loss rate was significantly higher (p = less than 0.05) when sampled before 12 weeks (TC-CVS 6.2 per cent, TA-CVS 5.8 per cent). When the CVS (TA) was performed after 12 weeks the fetal loss rate decreased to 2.4 per cent. In 1079 younger women the fetal loss rate remained low (TC 2.8 per cent; TA less than 12 weeks 1.8 per cent; TA greater than 12 weeks 1.7 per cent) and was not influenced by gestational age at the time of sampling. We concluded both methods safe and reliable when the choice of application considers maternal age.     

Tetrasomy 12p--unusual presentation in CVS

CVS direct preparations usually achieve limited resolution and are better at detecting numerical rather than structural abnormalities. A CVS direct preparation analyzed using G-banding revealed a 47,XY,+G karyotype in 5 of 11 cells and was reported as mosaic for trisomy 21. Subsequent analysis of the CVS culture found only normal male cells. Amniocentesis revealed both normal male cells and cells with an extra F-group chromosome. Fluorescence in situ hybridization (FISH) identified this chromosome to be an isochromosome from the short arm of chromosome 12 [i(12)(p10)]. The amniocyte karyotype was reported as 47,XY,+i(12)(p10)[12]/46,XY[8].ish i(12)(p10)(wcp12+), which is associated with Pallister-Killian syndrome. Reexamination of the CVS direct preparation by FISH with a chromosome 12 centromere probe confirmed the karyotype of this tissue to be 47,XY,+mar[5]/46,XY[6].nuc ish 12cen(D12Z3 x 3)/12cen(D12Z3 x 2). Thus, multiple studies, including amniocentesis and fluorescence in situ hybridization, may be required to fully and accurately evaluate abnormalities detected by CVS. This case also indicates that mosaicism for supernumerary isochromosomes may have a complex origin.     

Chorion villi sampling (CVS) for prenatal diagnosis of genetic disorders: first results and future research

Chorion villi sampling (CVS) in the first trimester of pregnancy has become available recently as an alternative method to second trimester amniocentesis for prenatal diagnosis of genetic defects. Currently there are six different tissue sampling techniques being investigated in different centers around the world, but there are very few trials in ongoing pregnancies. From chorionic villi material cytogenetic and biochemical studies as well as DNA analyses can be performed. Different methods of chromosome analysis are being investigated at the University of California San Francisco and elsewhere to determine the most efficient and reliable techniques. Larger studies will be needed to establish the efficacy and the safety of the chorionic villi sampling procedure for the mother and the developing fetus. Although CVS is preferable to amniocentesis for psychological and medical reasons (earlier elective termination of a fetus with a genetic disorder), many questions remain to be answered in carefully controlled studies.     

Pain with Amniocentesis and Transabdominal CVS

Fifty consecutive patients undergoing transabdominal chorionic villus sampling (CVS) and 52 undergoing amniocentesis completed a questionnaire following the procedure to determine the amount of pain they experienced. Mild pain, discomfort only or no pain was reported by 96% undergoing amniocentesis and 90% with CVS. Moderate or severe pain was reported after completion of the CVS by 8% and following amniocentesis by 2%. Both procedures were well tolerated.     

Prenatal diagnosis of trisomy 20 by chorionic villus sampling (CVS): a case report with long-term outcome.

A case of prenatally diagnosed non-mosaic trisomy 20 in cells cultured from a chorionic villus sample (CVS)is presented. The term placental karyotype was also non-mosaic trisomy 20. The karyotype of the newborn was 46,XY/47,XY,+20 in foreskin cultures and in a second skin culture; blood lymphocyte culture was 46,XY. Aside from diffuse, hypopigmentary swirls along the lines of Blaschko observed on his extremities and trunk, referred to as hypomelanosis of Ito, the patient is clinically normal at 8 3/4 years of age. In addition, he is one of the oldest reported cases of mosaic trisomy 20 confirmed after birth for which the clinical outcome has been monitored. This case demonstrates that these trisomy 20 findings are compatible with normal psychomotor development and phenotype.     

Risk factors associated with transcervical CVS losses.

Factors found to be associated with pregnancy loss after transcervical CVS were race (higher for non-white), history of spontaneous abortion, unplanned pregnancy, history of spotting or bleeding during the pregnancy prior to CVS, and placental position (higher for fundal or lateral locations). Whether the increase in loss risk is due to the factor, per se, or the factor plus the CVS cannot be determined due to the lack of appropriate control data.     

Translocation trisomy 21 in CVS not found in embryoblast: three different cell lines in CVS, amnion- and placental culture

Chorionic villus samples from a healthy pregnant female were obtained for first-trimester prenatal diagnosis. A translocation trisomy 21 was diagnosed. A consecutive amniocentesis revealed a normal male karyotype. At term a healthy boy was born. Cytogenetic analysis from cord blood showed a regular karyotype of 46,XY, whereas in term placenta a pathological karyotype of 47,XY, +mar was found.     

Fetal limb constriction: a possible complication of CVS

A case of fetal loss due to infection after first-trimester chorionic villus sampling is described. The fetus was born at 18 3/7 weeks and showed an annular constriction of one of the arms as seen in the amniotic band sequence. Induction of congenital defects might be one of the complications of chorionic villus sampling.     

Non-concordance of CVS and liver glycine cleavage enzyme in three families with non-ketotic hyperglycinaemia (NKH) leading to false negative prenatal diagnoses

We report three false negative prenatal diagnostic results, using direct measurement of glycine cleavage enzyme activity in uncultured chorionic villus tissue from 290 pregnancies at risk for non-ketotic hyperglycinaemia (NKH). Testing was done by two centres: Vancouver, Canada and Lyon, France. One false negative result had activity near the lower limit of the normal range but two samples gave completely normal results well within the control range. All three pregnancies continued and the three children were born affected with NKH. Because of the first result, we now counsel that there is a grey zone of uninterpretable activity where affected and normal enzyme values overlap. Because of the other two results we now counsel that there is an approximately 1% chance of a pregnancy with a normal CVS activity resulting in an affected child. The clinical and biochemical findings in the three families are discussed.