Transcervical chorionic villus sampling beyond 12 weeks of gestation

The aim of this study was to evaluate the feasibility of transcervical chorionic villus sampling (CVS) after 12 completed weeks of pregnancy. The transcervical route for CVS, using thin biopsy forceps, was accomplished in 335 procedures in the study group, between 12 + 1 and 15 + 0 weeks. Cases were subdivided into two subgroups, the late (13 + 0 to 15 + 0 weeks) and intermediate (12 + 1 and 12 + 6 weeks) subgroups, and the results were compared with a previous series of 1202 early (8 + 0-12 + 0 weeks) transcervical CVS. A successful diagnosis was made in 97.3% of the cases. No differences were found in diagnostic success between the study subgroups, in comparison to the early transcervical CVS series. However, success rates in the study group increased from 90% in the first 60 procedures to 98.9% in the remaining cases (p < 0.001). Amniocentesis was eventually performed in nine cases (2.7%). All cases were rescanned 2 weeks after the procedure, and fetal demise was detected in five cases (1.5%). The spontaneous fetal loss rate up to 28 weeks was 3.1% (2.7% for intermediate and 4.0% for late subgroups). No cases of transverse limb reduction defects were observed. The results of our study suggest that the transcervical route for CVS beyond the 12th week of pregnancy has a satisfactory diagnostic success rate, and an acceptable pregnancy loss rate.