Why cell culture is successful after early amniocentesis

The current interest in early amniocentesis as a possible alternative to chorion villus sampling has driven many centres to attempt cell culture from first trimester amniotic fluid. This study examines the cellular content of 125 amniotic fluid specimens collected between 8 and 18 weeks of gestation and shows that there is a higher proportion of viable cells at the time of early amniocentesis than at traditional amniocentesis. Although there is a small increase in viable cell number from 8 to 18 weeks of gestation, this is not as dramatic as the exponential rise in total cell number seen over the same period. The similar concentration of viable cells in early pregnancy to that in the second trimester is sufficient to explain the unexpected culture success after early amniocentesis.