Transabdominal Chorionic Villus Sampling Research Articles

The effect of chorionic villus sampling on the number of fetal cells isolated from maternal blood and on maternal serum alpha-fetoprotein levels

Fetal cells are present in the circulation of pregnant women and can be isolated using density gradient centrifugation and magnetic cell sorting. In the present study, maternal cell preparations were depleted for CD45- and CD14-positive cells and enriched for CD71-positive cells. The number of fetal nucleated cells was determined using fluorescence in situ hybridization for X and Y chromosomes. Analysis of maternal blood samples taken before and after transabdominal chorionic villus sampling (TA-CVS) showed an increase in the number of fetal cells in 10 out of 19 male pregnancies after the invasive procedure. This cellular transfusion was found to correlate with elevated maternal serum alpha-fetoprotein levels. TA-CVS-induced cellular transfusion may form a good in vivo system to optimize fetal cell isolation procedures and to study fetal cell dynamics and characteristics.

First trimester fetal heart rate: response to chorionic villus sampling in the chromosomally normal fetus.

The objective of this prospective study was to evaluate the fetal heart rate before and after the procedure and whether this had any effect on the risk of pregnancy loss following chorionic villus sampling (CVS) and chromosomally normal pregnancies. Four hundred and seventeen pregnancies were evaluated. The heart rate before the procedure was similar for both male and female fetuses. Significant procedure-related changes in fetal heart rate occurred only with male fetuses undergoing the transabdominal CVS technique. Fetal heart rate decelerations following CVS were more common than accelerations. Fetal heart rate changes following CVS were not able to predict the pregnancies ending in spontaneous abortion. Transabdominal CVS had a lower loss rate after the procedure, compared to the transcervical technique (p = 0.0001). Small-for-date fetuses had a higher loss rate after the procedure compared to normal-sized fetuses (p = 0.001).

Ketoacids attenuate glucose uptake in human trophoblasts isolated from first-trimester chorionic villi

OBJECTIVE: The objective of this study was to evaluate the hypothesis that ketoacids (acetoacetic acid and β-hydroxybutyrate) diminish glucose transport in trophoblasts cultured from first-trimester chorionic villi. STUDY DESIGN: First-trimester trophoblasts were obtained by transabdominal chorionic villus sampling for subsequent cytogenetic analysis. The cells were established as a continuous line exhibiting trophoblast characteristics. Trophoblasts were cultured in Ham's F12/Dulbecco's modified Eagle's medium (1:1) supplemented with 15% fetal bovine serum. Experiments were initiated by a 24-hour preincubation in serum-free Ham's F12/Dulbecco's modified Eagle's medium followed by incubation with ketoacids (acetoacetic acid and β-hydroxybutyrate, 0 to 10 mmol/L) in the presence or absence of insulin-like growth factor-I (100 ng/ml). The cells were challenged with 2-deoxy-[1,2- 3H] D-glucose (0.1 mmol/L) for 5 minutes and then cell-associated radioactivity was measured. Total ribonucleic acid was extracted from cells incubated with ketoacids in the presence or absence of insulin-like growth factor-I, and Northern blots were probed with a phosphorus 32 - labeled complementary deoxyribonucleic acid fragment encoding the rat GLUT 1. RESULTS: Ketoacids caused a dose-dependent inhibition of glucose transport. At 5 mmol/L acetoacetic acid there was a >50% reduction in the rate of glucose transport in both control and insulin-like growth factor-I - treated cells. The diminution in glucose uptake by trophoblasts was not due to cellular toxicity of the ketoacids because there was no significant difference in trypan blue exclusion or lactate dehydrogenase release between control and ketoacid-treated cells. Northern analysis revealed that the steady-state expression of GLUT1 messenger ribonucleic acid was diminished in ketone-treated cells, but this effect was overcome by coincubation of cultures with insulin or insulin-like growth factor-I. CONCLUSIONS: These results indicate that ketoacids can suppress the uptake of glucose into first-trimester human trophoblasts. Because ketoacidosis in pregnant women with diabetes mellitus is a frequent clinical consequence of poor metabolic control, it is possible that elevated levels of acetoacetic acid and β-hydroxybutyrate may impair the transport of glucose across the placental trophoblast and into the fetal circulation. (Am J Obstet Gynecol 1996;175:56-62.)

Comparison of transcervical and transabdominal chorionic villus sampling loss rates in nine thousand cases from a single center

OBJECTIVES: Our purposes were (1) to compare the safety of transabdominal and transcervical chorionic villus sampling with the use of a consistent technique at one center and (2) to determine whether the training of fellows can be accomplished without an increase in the loss rate. STUDY DESIGN: We performed a retrospective comparison of transabdominal and transcervical chorionic villus sampling loss rates from procedures performed by three principal operators between 1984 and 1992. The type of procedure was chosen by the operator at the time of the procedure on the basis of placental location. RESULTS: Procedures 1 through 2573 were performed solely by transcervical chorionic villus sampling and had an overall fetal loss rate 5.12%. With the addition of transabdominal chorionic villus sampling the overall fetal loss rate dropped to 3.07% p < 0.0001). Three and one half years after the start of transabdominal chorionic villus sampling (about 1300 transabdominal chorionic villus sampling procedures), the transabdominal chorionic villus sampling loss rate was significantly better than the transcervical loss rate ( p = 0.035), and the difference widened steadily after that. During the same time period seven fellows performed 716 procedures for a fetal loss rate among fellows of 2.72%. CONCLUSIONS: (1) Under optimal circumstances (one center, large numbers, few operators, consistent technique, operator choice of best approach), transabdominal chorionic villus sampling may be inherently safer than transcervical chorionic villus sampling. (2) The addition of transabdominal chorionic villus sampling decreases overall chorionic villus sampling loss rates. (3) Although the number of procedures performed by fellows is small, it appears that with close supervision by experienced operators successfull training of fellows can be accomplished without adverse effects on loss rates.

Fetal ductus venosus flow velocity waveforms and maternal serum AFP before and after first-trimester transabdominal chorionic villus sampling.

Doppler flow velocity waveform recording in the fetal ductus venosus and umbilical artery as well as maternal blood sampling for serum alpha-fetoprotein (MSAFP) was performed before and after transabdominal chorion villus sampling (TACVS) in 36 women of advanced maternal age (> or = 36 years). Gestational age ranged between 11 and 13 weeks. No chromosomal anomaly was detected. No statistically significant difference was observed in ductus venosus velocity parameters or in the umbilical artery pulsatility index (PI) before and after CVS in 35 women with a normal pregnancy outcome. One case resulted in fetal loss. Post-CVS median MSAFP levels at 12 weeks (25 kIU/l) and 13 weeks (35 kIU/l) were significantly higher than pre-CVS levels. In three cases, post-CVS MSAFP levels were higher than 600 kIU/l, correlating with feto-maternal transfusions of approximately 1.0-1.4 ml, i.e., of around 40 per cent of feto-placental blood volume. One of these cases displayed absence of fetal peripheral blood flow velocities and fetal bradycardia following TACVS, resulting in fetal loss 1 week later. The remaining two cases had a normal pregnancy outcome, but showed a more than 50 per cent reduction in ductus venosus velocity after TACVS, whereas umbilical artery PI remained unchanged. However, similar velocity changes were associated with only small feto-maternal transfusions. Umbilical artery PI values remained unchanged.

Prenatal diagnosis by transabdominal chorionic villus sampling in the second and third trimesters

Prenatal diagnosis by transabdominal chorionic villus sampling in the second and third trimesters

Early sonographically guided amniocenteses with filtration technique: follow-up on 249 procedures.

Fetal and neonatal outcome is reported for 249 consecutive low-risk pregnancies in which early amniocentesis was carried out with filter technique, at a mean gestational age of 12.5 weeks, to improve the yield in cell cultures. Three pregnancies (1.2%) were terminated because of abnormal test results, four stillbirths (1.6%) occurred between weeks 33 and 38, and five pregnancies were lost spontaneously after sampling, corresponding to 2% of unintended fetal losses before 28 weeks of gestation. Of the live-born infants, 2.9% were delivered prematurely, all between weeks 32 and 37. Malformations and orthopedic postural deformities were not associated with leakage after amniocentesis and were found at expected rates. None of the cases was lost to follow-up. The increase in abortion rate caused by early amniocentesis with filter technique is likely to be within the same range as that seen after routine amniocentesis and transabdominal chorionic villus sampling, although the sample is too small for a proper risk evaluation.

Early amniocentesis.

Amniocentesis before 15 weeks has been introduced in many prenatal diagnosis centres. There are, however, major anatomical differences between the appearance of fetus at 15-16 weeks, when amniocentesis has normally been performed, and in the first and early second trimester. This is mainly because of the presence of extraembryonic coelome and the relatively small amount of amniotic fluid in early pregnancy. Several small cohort studies have indicated no increased fetal loss rate with early amniocentesis. Others have suggested an increased risk of respiratory distress among the newborn. The only randomized study published, however, found a significantly increased rate of fetal losses after early amniocentesis. This incomplete study indicates the urgency of further randomized studies of early amniocentesis. A randomized study comparing early amniocentesis with transabdominal chorionic villus sampling is being undertaken at our centre in Copenhagen using a filter method that reduces the volume of fluid needed for karyotyping.

First‐trimester ultrasound screening for fetal aneuploidies in women over 35 and under 35 years of age

In a prospective screening study, the utility of the thickness of first-trimester simple hygroma in sonographic screening for fetal chromosomal aberrations was examined. A total of 3380 women, 1280 of whom were 35 years or over, and 2100 of whom were under 35 years, were screened by ultrasound at 9-12 weeks of gestation. The thickness of fetal nuchal simple hygroma was measured. Women over 35 years of age underwent transabdominal chorionic villus sampling (CVS). In women under 35 years of age, CVS was offered only if the thickness of nuchal hygroma was at least 3 mm, or in cases of parental chromosomal abnormalities. A total of 46 chromosomal anomalies were detected, of which 43 (93.5%) showed simple hygroma. The incidence of first-trimester simple nuchal hygroma in pregnancies of women over 35 and under 35 years of age was 5.4% (69 cases) and 1.28% (27 cases), respectively, and the percentage of chromosomal abnormalities was 2.9% and 0.43%, respectively. The risks of trisomies and poor pregnancy outcome were increased at larger sizes of first-trimester simple hygroma. A sensitivity of 93.5% and a specificity of 98.4% of the method were found. Using a measurement of first-trimester simple hygroma of > or = 3 mm to identify pregnancies at risk for chromosomal anomalies at 9-12 weeks of pregnancy is a useful method for selection of women with high and low risk for aneuploidy.

Prenatal diagnosis by transabdominal chorionic villus sampling in the second and third trimesters

From October 1989 through December 1993, 124 pregnant women (114 in the second trimester and 10 in the third trimester) underwent transabdominal chorionic villus sampling (CVS) for prenatal molecular or cytogenetic diagnosis. The mean gestational age was 18.2 weeks. Indications for CVS comprised single gene disease (72%), fetal anomalies detected by ultrasound (17%), advanced maternal age (6%), and previous siblings with chromosomal aberration (5%). Among the 89 fetuses at risk for single gene disease, 20 were diagnosed as affected by DNA analysis. Among the 35 fetuses at risk for chromosomal anomaly, 4 had trisomy, 3 had a 45,XO karyotype and 2 had a structural chromosomal abnormality. The miscarriage rate was 1.8% (2/114) and the spontaneous preterm birth rate was 2.4% (3/124). No maternal or other fetal complications occurred. This study suggested that second- and third trimester CVS is a safe and useful method for prenatal diagnosis.

Comparison of transcervical and transabdominal chorionic villus sampling in 9000 cases from a single center: [formula omitted]x, M. Wohlferd, J. Goldberg, M. Golbus x. Dept. Ob/Gyn, UCSF, San Francisco, CA

Comparison of transcervical and transabdominal chorionic villus sampling in 9000 cases from a single center: [formula omitted]x, M. Wohlferd, J. Goldberg, M. Golbus x. Dept. Ob/Gyn, UCSF, San Francisco, CA

Fetal therapy: ethical, legal and medical considerations

Our ability to detect fetal abnormalities has increased substantially over the last 2 decades. Radiology, occasionally still used for diagnosis of skeletal abnormalities, has been largely superseded by the safety, ease of application and flexibility of ultrasound scanning. An experienced sonographer with a sophisticated machine can delineate structural abnormalities which when categorised act as phenotypic markers of chromosomal aberration or malformation syndromes. Invasive procedures for prenatal diagnosis have also undergone rapid evolution. Amniocentesis for biochemical analysis of liquor amnii or cytoculture of amniocytes for karyotyping was followed by placentacentesis to obtain fetal blood to exclude haemoglobinopathies such as thalassaemia and sickle cell disease.’ Fetoscopy, which allowed direct visualisation of the mid-trimester fetus added precision to gain access to fetal blood or tissue.2 This sizeable instrument is 2.2-3 mm in diameter hence post procedural leakage of amniotic fluid and an associated fetal loss rate of approximately 5’K3 Once sophisticated sonography became available less traumatic access to pure fetal blood was obtained by needle placement to the umbilical cord, the hepatic vein and, less satisfactorily, the fetal heart.4 In the second trimester rapid (results available in 24-48 h) karyotyping by transabdominal chorion villus sampling can be performed.5*6 This same tissue can be collected for prenatal diagnosis in the first trimester.‘** Both the abdominal and transcervical routes are shown to be safe and acceptable techniques for villus sampling at this stage.’ This is currently

Transabdominal chorionic villus sampling and amniocentesis for prenatal diagnosis: 5 years' experience at a University Centre

The fetal loss rates and fetal congenital birth defects in 821 transabdominal (TA) chorionic villus sampling (CVS) and 771 amniocentesis (AC) cases were evaluated from a 5-year period (1987-1991) at the University Central Hospital of Turku. The parents were given the option of choosing between the two sampling procedures. CVS was performed, in most cases, at 11 weeks of gestation; and AC, at 15 weeks. The rate of total post-procedure loss was 6.7 per cent in the CVS group and 4.4 per cent in the AC group (p = 0.08). The rate of spontaneous abortions was 1.9 per cent in the CVS group and 1.0 per cent in the AC group (p = 0.10). The number of birth defects was low in both study groups. No limb reduction cases were observed. Mosaicism was noted in 14 CVS cases and in five AC cases. We conclude that TA-CVS is a safe and practical alternative to AC in prenatal fetal karyotyping.

Implications of maternal serum alpha-fetoprotein elevation caused by transabdominal and transcervical CVS.

Of 2882 women allocated to either transabdominal CVS (TA) or transcervical CVS (TC) at two large obstetric centres in Denmark, 2707 had blood samples drawn before and 30 min after CVS for maternal serum-alpha-fetoprotein (MSAFP) measurement. 2535 of these women had cytogenetically normal pregnancies and 2091 of them went on to have samples drawn at the 18-20 week follow-up. Post-procedure MSAFP values were correlated to the biopsy method used, with mean MSAFP values significantly higher after TA than TC, 33 and 15 kU/l, respectively (P < 0.001). Following TA procedures, 18 per cent of cases had feto-maternal transfusion higher than 0.1 ml; this occurred in only 5 per cent of TC cases. MSAFP levels were associated with spontaneous fetal loss in the TA group but not in the TC group. TC, however, was followed by more losses than TA. The post-CVS MSAFP value was positively correlated with the amount of villi aspirated. The difference in post-procedure elevation in MSAFP 30 min later (average 18 kU/l higher for TA than for TC) was not reflected in raised levels at the 18-20 week follow-up. Study medians at mid-trimester did not differ from reference group medians established from a group of singleton pregnancies with sonographically determined gestational age who did not experience invasive procedures and delivered normal infants. Our findings suggest that CVS does not compromise mid-trimester MSAFP for screening for neural tube defects (NTDs). Extremely high mid-trimester MSAFP values in the TC group could predict imminent loss.

Technical aspects of transcervical chorionic villus sampling.

Following the 1990 FDA approval of the Trophocan catheter for use in transcervical chorionic villus sampling (CVS), an increasing number of US physicians have begun offering the procedure. To obtain privileges to perform CVS, some states such as California have enacted legislation requiring the performance of a certain number of CVS procedures in pregnancies in which the patient has already chosen first-trimester abortion. This practice is not universally feasible for legal, logistic, or financial reasons. We describe our approach to training in a busy reproductive genetics service. The physician initially trains by performing amniocentesis to optimize skills in ultrasound-directed needle guidance and placement. During this initial period, he or she also assists in performing transabdominal CVS procedures. The initial transcervical CVS cases should be performed in those situations requiring minimal catheter manipulation, or in those individuals undergoing CVS in the setting of spontaneous abortion. Cases of increasing difficulty should only be performed as skill and familiarity increase. For a physician already skilled and experienced in ultrasound-guided invasive procedures, sequential periods of observation at a busy center allows him or her to become familiar with the common pitfalls in performing transcervical CVS, and thus avoid them. Using this approach, we have performed over 5,000 CVS procedures and trained 6 reproductive genetics fellows in transcervical CVS.

Transabdominal chorionic villus sampling in the second and third trimesters of pregnancy: chromosome quality, reporting time, and feto-maternal bleeding.

Transabdominal chorionic villus sampling (TA-CVS) was performed in 210 pregnancies from 13 to 38 weeks using a double-needle technique. The sampling success was comparable to first-trimester TA-CVS and the diagnostic success rate was 98.2 per cent for the short-term technique and 99.3 per cent for cultured villi. Two fetuses could not be karyotyped. We found the chromosome quality to be similar to that in the first trimester, comparing the number of G-bands and other chromosome attributes. There were no unintended losses in a group (n = 142) with no sonographic abnormality, except for one death in utero at 38 weeks, 20 weeks after sampling. Chromosomal aberrations were seen in 19 per cent of cases with abnormal sonograms (n = 58). One cases of a discordant karyotype was found (false-negative prediction of Down's syndrome by the short-term preparation). There were no cases of fetal demise due to feto-maternal bleeding. It is suggested that double-needle TA-CVS in advanced pregnancies combines the advantages of rapid karyotyping of chromosomes of good quality and low risk for the fetus, and seems to be easier to practise and is probably safer than cordocentesis.

Terminal transverse limb defects and early chorionic villus sampling: Evaluation of 4,300 cases with completed follow‐up

Data from 4,300 consecutive cases following prenatal diagnosis by transcervical (TC) CVS (n = 1,570) and transabdominal (TA) CVS (n = 2,370) were evaluated. In the follow-up study only infants examined by a physician were included. Gestational age varied between 8.5 and 11.6 weeks (mean 10.3 weeks) for TC-CVS and between 9.3 and 20 weeks (mean 12.3 weeks) for TA-CVS 98% of TC-CVS was performed at 9-10 weeks, 80.7% of TA-CVS procedures were carried out at 12-15 weeks. Selective termination took place in 97 cases of TC-CVS (6.1%) and in 72 cases of TA-CVS (2.6%). Another 8 women had a termination for psychosocial reasons, resulting in 4,123 (1,469 TC, 2,654 TA) continuing pregnancies. The overall fetal loss rate < 28 weeks was 5.4% (n = 80) for TC-CVS and 2.6% (n = 70) for TA-CVS. The overall incidence of congenital abnormalities after birth was 0.9%. Two terminal transversal limb defects were detected in the TC-CVS group (0.14%) against one (0.04%) in the TA-CVS group.

Chorionic Villus Sampling: Transabdominal Versus Transcervical Approach in More Than 4000 Cases

To address the evolving trends in the choice of transabdominal or transcervical chorionic villus sampling (CVS) at a teaching hospital and to evaluate the influence of gestational age on the approach chosen.We analyzed our CVS data base, which contained information from 1986-1991. The proportions of transabdominal and transcervical CVS were tabulated for each year. In addition, the distribution of the CVS approaches over the various gestational ages was examined.During the study period, 4290 CVS procedures were performed. The rate of the transabdominal technique was stable at about 15% per year except for the first 2 years, when essentially all procedures were transcervical. Use of transabdominal CVS increased with advancing gestational age, from 3.6% at less than 10 weeks' gestation to 97.6% at greater than 14 weeks (chi 2 = 120, P less than .001; r = 0.791).The choice between the transabdominal and transcervical approach to CVS largely reflects the route emphasized during the physician's training. When choice is based strictly on technical limitations due to placental position, the overall transabdominal CVS rate is approximately 15%. A shift from transcervical to transabdominal CVS occurs with increasing gestational age as the placenta gains bulk and moves away from the cervix. After 14 weeks' gestation, most procedures are performed transabdominally.

Early transabdominal chorionic villus sampling in couples at high genetic risk

The purpose of the study was to evaluate the feasibility and safety of transabdominal chorionic villus sampling before 9 weeks' gestation. Two hundred pregnancies at risk for beta-thalassemia (n = 198) or Duchenne muscular dystrophy (n = 2) underwent transabdominal CVS at 6 through 8 weeks. Sampling success and fetal loss are expressed in percentages. Sampling was successful in all cases (100%). Forty-eight fetuses were affected by beta-thalassemia and one by Duchenne muscular dystrophy. The percentage of fetal loss, expressed as a proportion of continuing pregnancies, was 4.0%. All women (n = 144) have been delivered, and no misdiagnoses have occurred. We observed one anencephalus and one mild limb defect consisting of absence of distal phalanges of index and little fingers of both hands and distal phalanges of both little toes. Transabdominal CVS before 9 weeks is a reliable and relatively safe method for prenatal diagnosis in patients at high risk for genetic diseases. However, further studies are necessary to assess the risk to the fetus.

Randomised comparison of amniocentesis and transabdominal and transcervical chorionic villus sampling

We have compared three methods of prenatal diagnosis in two large obstetric centres in Denmark. Women were randomly assigned transabdominal (TA) chorionic villus sampling (CVS), transcervical (TC) CVS, or second-trimester amniocentesis (AC); women at high genetic risk were randomised between the two CVS groups only. Analysis of 45 epidemiological variables showed the three procedure groups to be similar at enrolment. All women were followed up until completion of pregnancy. Among 3079 women at low genetic risk total fetal loss rates were 10·9% for TC CVS, 6·3% for TACVS, and 6·4% for AC (p<0·001). More women had bleeding after the procedure in the CVS groups (p<0·001), whereas more amniotic fluid leakage (p<0·001) was reported after AC. No uterine infections occurred in any group. No case of oromandibular-limb abnormality was seen in the CVS groups, but 1 child in the AC group had aplasia of the right hand. The two CVS approaches were compared among 2882 women at low and high genetic risk who were found to have cytogenetically normal fetuses. Rates of unintentional loss after the procedure were 7·7% for TC CVS and 3·7% for TA CVS (p<0·001; 95% Cl of difference 2·3-5·8%). At baseline ultrasound scanning after establishment of optimum sampling conditions, more TC than TA procedures (p<0·001) were judged not to be feasible. We found that TA CVS allows better access to the placental site than TC sampling, is an easier skill to acquire, and has the potential that more villi can be aspirated when needed. The risk of fetal loss is similar after TA CVS and AC. However, losses after AC are at a later stage and are therefore more distressing. TA procedures remain the first choice for prenatal diagnosis. Since, in our hands, TC sampling carries a greater risk to the fetus, we have abandoned TC CVS in our two study centres.