Chorionic Villus Sampling

Chorionic villus sampling in the first trimester of pregnancy has the potential to become a major tool in the prenatal diagnosis and therapy of genetic disorders. Villus samples can be used for cytogenetic and biochemical studies as well as DNA analysis. However, little is known about the effects of chorionic villus sampling on a continuing pregnancy, or the long-term effects on the subsequently delivered infants. Despite these limitations, chorionic villus sampling appears to be a major breakthrough in prenatal diagnosis.     

Transabdominal Chorionic Villus Sampling

The first 100 patients undergoing first trimester transabdominal chorionic villus sampling (placental biopsy) in our hospital are reviewed. At the time of follow up 24 patients had delivered, 68 pregnancies were at 24 weeks or more and progressing normally, 7 pregnancies were terminated and there was only 1 spontaneous miscarriage. The advantages of the transabdominal approach are discussed.     

Developmental Origin of Chorionic Villus Cultures From Spontaneous Abortion and Chorionic Villus Sampling

ObjectiveChorionic villus cultures from spontaneous abortions and chorionic villus sampling (CVS) are routinely used for clinical cytogenetic analysis. Although these cultures are assumed to represent the chorionic villus mesenchymal core, and therefore the inner cell mass (ICM) of the blastocyst, immunochemical studies using a true trophoblast-specific marker to definitively rule out trophoblast contamination have not been done. Therefore, we used cytokeratin-7 (CK7), a trophoblast-specific marker, to assess the developmental origin of these chorionic villus cultures.MethodsWe assessed chorionic villus cultures from CVS and spontaneous abortions for CK7 immunostaining (n = 20).ResultsCultures from both CVS and spontaneous abortions showed little or no CK7 staining (≤ 1%).ConclusionChorionic villus cultures from CVS and spontaneous abortions exhibit little or no trophoblast contamination. They are therefore representative of the villus mesenchymal core and ultimately originate from the ICM of the blastocyst.     

Chorionic Villus Sampling in cytogenetic analysis--disadvantages and advantages

Chorionic villus sampling is used in prenatal diagnosis, enabling to detect fetal genetic abnormalities. Its advantages include the possibility of performing the procedure during the first trimester of pregnancy relatively fast result, risk of miscarriage comparable to that in case of amniocentesis. The disadvantages of this method are: difficult cytogenetic analysis, the possibility of contamination with maternal cells and the risk of mosaicism. There should always be a valid indication to perform the CVS procedure.     

Development of a High-Fidelity Simulator for Teaching Chorionic Villus Sampling

Objective

The objective of this study was to develop a synthetic high-fidelity simulator for teaching chorionic villus sampling.

经宫颈绒毛取材用于地中海贫血产前诊断883例分析

目的:对有可能生育地中海贫血(地贫)高危胎儿的孕妇,在早孕期经宫颈绒毛活检(TC-CVS)用于地贫产前诊断,评价,TC-CVS在产前诊断中的应用价值.方法:对883例孕9～11周行地贫产前诊断的孕妇进行经宫颈绒毛活检,抽取绒毛行地贫基因分析产前诊断.随访观察孕妇的取材成功率、流产率、感染率.结果:取材成功率95.36%,自然流产率4.3%,宫内感染率1.13%.地贫基因分析共检出重型地贫儿143例,HbH病26例,α和β地贫杂合子共373例.结论:经宫颈绒毛活栓是一项安全可行的介入性产前诊断方法,用于早孕期地中海贫血产前诊断,可有效地检出重型地贫儿及各种地贫杂合子.     

Chorionic Villus Sampling: Cytogenetic Experience in Preliminary Investigations and in 50 Diagnostic Cases

The results of preliminary cytogenetic investigations of chorionic villus sampling (CVS) and its diagnostic application in 50 cases are reported. Preliminary investigations included the effect of short delays between biopsy and processing, levels of mitotic activity related to variations in processing, the incidence of tetraploidy, correlation of the karyotype of the chorionic villi with that of the fetus, and the results of banding studies. A protocol was then designed for application to diagnostic CVS. The 50 diagnostic cases included 4 with male karyotypes which were terminated due to a family history of an X-linked disorder, 1 trisomy 21, 1 trisomy 18, the finding of 1 aberrant cell out of 50 in an otherwise normal analysis, a 45, XY, t (13;21) karyotype, 2 fragile X negative karyotypes and in one case the presence of mosaicism was detected in chorionic villi and subsequently not confirmed at amniocentesis. The karyotype on the chorionic villi was 46XY/47XY +3.     

Completed Follow-up of 1,000 Consecutive Transcervical Chorionic Villus Samplings Performed by a Single Operator

Completed follow-up data on 1,000 patients undergoing transcervical chorionic villus sampling (CVS) performed by a single operator at the Royal Hospital for Women is presented. Prior to the introduction of CVS, approximately 750 amniocenteses were performed annually in this unit. Over the past 5 years the total number of patients having CVS or amniocentesis has increased by 1/3 and almost 1/2 of procedures are now done by CVS. We have persisted with the transcervical route believing that once the learning curve is past, this route compares favourably with the transabdominal method in loss rate and perinatal outcome. We feel the transcervical approach is better tolerated by our patients and that less procedural difficulties are encountered. With increasing operator experience the total fetal loss rate to 20 weeks' gestation in our series declined to 2.1% and late complications were no more frequent than expected. In 98.4% of patients, sufficient villi were obtained for analysis. Culture failure was extremely uncommon, occurring only twice in our series. In 1.5% of patients, a follow-up amniocentesis was required, which compares favourably with other published series. It appears that many units abandoned the transcervical route before loss rates were stabilized. In units where transcervical CVS is still performed the transabdominal route is also utilized. The reverse is not true. The authors feel that both procedures have a role in modern antenatal diagnosis.     

Incidence and birth weight characteristics of twins born to mothers aged 40 years or more compared with 35-39 years old mothers: a population study

OBJECTIVE: To compare the incidence of twin births and their birth weight characteristics in mothers aged > or = 40 years with those of mothers aged 35-39 years. METHODS: We used a population-based cohort of Israeli twins delivered between 1993-98 to compare birth weight characteristics of 510 and 2102 twin pairs delivered to mothers aged > or = 40 years (cases) and 35-39 years (controls), respectively. RESULTS: The incidence of twin mothers aged 40 years or more increased 50% during the study period, ten times more than mothers aged 35-39. There were significantly more nulliparas (P < .001, OR 1.54, 95% CI 1.2, 1.9) and more para > or = 4 (P < .004, OR 1.38, 95% CI 1.1, 1.7) among older mothers. Irrespective of parity, there were no significant differences between mean twin birth weight, total twin birth weight < 3000 g, 3000-4999 g, and > or = 5000 g, and frequencies of very low birth weight neonates. CONCLUSIONS: Twin birth at the age of > or = 40 years is significantly more likely among either nulliparas or para > or = 4. Birth weight characteristics of twins delivered to mothers aged > or = 40 years are not different from those delivered to 35-39 years old mothers.