COMPARISON OF TRANSCERVICAL AND TRANSABDOMINAL CHORIONIC VILLUS SAMPLING LOSS RATES IN 9000 CASES FROM A SINGLE-CENTER

OBJECTIVES: Our purposes were (1) to compare the safety of transabdomi nal and transcervical chorionic villus sampling with the use of a cons istent technique at one center and (2) to determine whether the traini ng of fellows can be accomplished without an increase in the loss rate . STUDY DESIGN: We performed a retrospective comparison of transabdomi nal and transcervical chorionic villus sampling loss rates from proced ures performed by three principal operators between 1984 and 1992. The type of procedure was chosen by the operator at the time of the proce dure 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 of 5.12%. With the addition of tra nsabdominal chorionic villus sampling the overall fetal loss rate drop ped to 3.07% (p < 0.0001). Three and one half years after the start of transabdominal chorionic villus sampling (about 1300 transabdominal c horionic villus sampling procedures), the transabdominal chorionic vil lus 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 f or a fetal loss rate among fellows of 2.72%. CONCLUSIONS: (1) Cinder o ptimal circumstances (one center, large numbers, few operators, consis tent technique, operator choice of best approach), transabdominal chor ionic villus sampling may be inherently safer than transcervical chori onic villus sampling. (2) The addition of transabdominal chorionic vil lus 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 successf ul training of fellows can be accomplished without adverse effects on loss rates.