Objective: This trial compared two instruments for transcervical chorionic villus sampling (CVS).
Design: Randomised controlled trial.
Setting: Regional university prenatal diagnosis and treatment centre.
Population: Two hundred women were randomised at 10(+0)-12(+6) weeks of gestation to transcervical CVS using cannula aspiration (CA) or biopsy forceps (BF).
Methods: Women undergoing indicated CVS signed informed consent. Randomisation after decision to perform transcervical CVS.
Primary outcome: the rise in maternal serum alpha-fetoprotein (alpha-FP).
Secondary outcomes: (i) placental trauma (fetomaternal haemorrhage [FMH]); (ii) laboratory, procedure, and cytogenetic results and pregnancy outcomes; (iii) patient and operator satisfaction; and (iv) economic analyses. Analyses were performed by intention to treat.
Results: The -FP rise did not differ between groups; there was no other evidence of placental trauma. BF were better tolerated by women, provided culturable tissue, after fewer instrument passes, with greater ease and in less time. BF were associated with cost savings.
Conclusions: Unlike -FP, other markers of FMH were unaltered, questioning the reliability of alpha-FP as an indicator of FMH. Compared with CA, transcervical BF caused comparable placental trauma, appeared to be similarly effective and safe and were preferred by operators and patients.