Transcervical versus Transabdominal Approach
Transcervical versus Transabdominal Approach
Brambati et alreported the results of a randomized trial of transabdominal versus transcervical CVS by a singleoperator in 1194 patients. Over 110 cases deviated from the allocated procedure, and more than 80% of the deviationsoccurred in the transcervical arm of the trial. Moreover, the proportion of cases in which the operator chose to deviatefrom the allocated procedure increased in each of the 3 years of the study (4.6%, 9.7%, and 15.5%, respectively). Morechorionic tissue was obtained by the transcervical method, but the proportion of cases in which less than 10 mg wasobtained was similar in both groups. Bleeding was more common following transcervical CVS, whereas cramping wasmore common with the transabdominal approach. No significant difference was detected in the overall rate of fetal loss(transabdominal approach, 16.5%; transcervical, 15.5%). The transabdominal technique required a significantly smallerproportion of repeat needle insertions (3.3% versus 0.3%), although this did not seem to affect pregnancy outcome.
There were also no differences in birth weight, gestational age at delivery, or congenital malformations. The authorscommented that a limitation of this study was the operator's eventual preference for the transabdominal approach. Theyconclude that the two techniques seem equally safe and effective, and the choice to perform one particular techniquemay depend largely on the operator's preference.
Jackson et alconducted a randomized comparison of transcervical and transabdominal CVS at 7 to 12 weeks ofgestation. Of 3999 eligible patients, 94% in each arm of the study underwent the allocated procedure. Only one needleinsertion was required in 94% of transabdominal CVS cases, and one catheter pass was required in 90% of transcervicalCVS procedures. The rate of fetal loss, excluding elective terminations of pregnancy, was 3% in each group.
Jensen et alpublished their randomized comparison of routine amniocentesis, transabdominal CVS, andtranscervical CVS in 3706 low-risk patients. Patients were randomly assigned to one of the three procedures. Theproportion of patients for whom a cytogenetic diagnosis was successfully obtained at the first attempt was 99.7% foramniocentesis, 98.1% for transabdominal CVS, and 96.0% for transcervical CVS ( P < 0.0001). Total rates of fetal losswere 10.9% for transcervical CVS, 6.3% for transabdominal CVS, and 6.4% for amniocentesis, a statistically significantdifference. A large difference was noted between the transabdominal and transcervical CVS groups in the proportion ofpostprocedural losses of cytogenically normal pregnancies (3.7% for transabdominal and 7.7% for transcervical CVS).The authors conclude that although transabdominal CVS and amniocentesis carry similar risks of fetal loss, transcervicalCVS is associated with an overall higher rate of fetal loss, estimated to be in excess of 4.0%.(RefDiagnosis and Management of the Fetal Patient 1st edition)