First trimester prenatal diagnosis: chorion villus sampling or amniocentesis

Cytogenetic aspects of the Canadian early and mid-trimester amniotic fluid trial (CEMAT)

“…It may be misleading to compare these mosaicism rates with those found in other laboratories at a later gestation because of potential differences related to the type of media used and other laboratory specific culture conditions. Neilson and Gosden (1991) suggested that since more than 70 per cent of cells in amniotic fluid up to 15 weeks are derived not from the fetus but from the membranes and trophoblast, there is a substantial possibility that confined placental abnormalities may be much more of a problem with first trimester than second trimester amniocentesis. Kerber and Held (1993) reported increased pseudomosaicism (levels I and II) in 10-14 week fluids compared with 16-18 week fluids, but not when compared with 15 week fluids.…”

The rise and fall of early amniocentesis

“…About seven years ago, the subject of early amniocentesis was addressed in a Commentary by Nielson and Gosden in this Journal 1 . The article was written at a time of decline in the fortunes of chorionic villus sampling as the definitive first trimester prenatal diagnostic test.…”

“…Laboratory techniques were also improving such that cytogenetic results from amni‐otic fluid less than 14 weeks of gestation was a possibility. Nielson and Gosden's commentary ended with the statement that ‘a large multi‐centre randomised controlled trial is now required to compare first trimester amniocentesis and chorionic villus sampling 1 . Furthermore, they stated that this should be not only an assessment of short term safety and accuracy but also long term follow up to identify any complications in children born.…”

First trimester prenatal diagnosis

“…We read with great interest the commentary by Neilson & Gosden (1991) concerning chorion villus sampling (CVS) or amniocentesis for prenatal diagnosis, which echoed the concerns of the MRC Working Party on the Evaluation of Chorion Villus Sampling (1991), that early amniocentesis should only be available within the confines of a randomized trial. We fully concur with this opinion and that is why we have been conducting a randomized trial of early amniocentesis and chorion villus sampling at 10–13 weeks gestation, sinceJanuary 1990.…”