Early second trimester (13 to 20 weeks) transabdominal chorionic villus sampling (TA-CVS): a safe and alternative...

To assess feasibility, effectiveness and risk of prenatal diagnosis by TA-CVS at 13-14 and 15-20 weeks' gestation.

CVS was performed transabdominally by free-hand single needle insertion technique under continuous ultrasound visualization on 1844 pregnant women, aged 18 to 48, at 13 to 20 weeks' gestation, whose primary indication was chromosomal anomalies and single gene defects in 85% and 15% of cases, respectively Clinical follow-up of women undergoing TA-CVS at 13 to 20 weeks' was prospectively obtained; the population was split in two groups of 13-14 (series B) and 15-20 weeks' (series C) gestation. Statistical evaluation included a group of TA-CVS cases performed at 11-12 weeks (series A).

Sampling was feasible in 98.2%, 99.1% and 95.8% of cases of series A, B and C, respectively. Sampling was successful in all cases of the three series and a second insertion was required in 1.5%, 1.3% and 0.9%, respectively. A trend towards lower fetal loss rate is apparent (1.02%, 0.86%, and 0.46 in series A, B, and C, respectively), although differences were not statistically significant. No post-procedural complications were reported for series B and C, while spotting was present in 1.8% of cases for series A. Karyotyping was totally successful by short term culture and was also available by long term culture in 99% of cases for series A, B and C when the amount of chorionic tissue was more than 15 mg.

TA-CVS appears highly effective and safe and might be offered as a valuable alternative to early as well as mid-trimester amniocentesis.