First trimester amniocentesis between the seventh and 13th weeks: Evaluation of the earliest possible genetic diagnosis

Abstract

Amniocentesis performed at the 12th week and later gives reliable results. The procedure can be performed using regimens developed for mid-trimester amniotic fluid (AF) cells. Extension to the 10th-11th week is, in principle, feasible. However, the high cytogenetic failure rate is a difficulty and despite a high clone count, the culture time is prolonged. The problem of the relatively high loss of AF could be overcome by cell filtration techniques and replacement of the fluid. Because of the short turnover rate of the AF, this may be unnecessary or replacement with an isotonic solution may be sufficient. (Pseudo)mosaicism appears to occur more frequently in early than in late amniocentesis. As yet, data are too sparse to allow a comparison with chorionic villus sampling. There are no reliable follow-up data from which to estimate the abortion rate and the number of embryonic malformations.

Early Amniocentesis at 10–12 Weeks' Gestation

“…This is in line with what most authors have indicated for amniocentesis before the 13th week (Hanson et al, 1992;Rebello et al, 1991;Farran et al, 1993;Schulman et al, 1994;Kerber and Held, 1993), but contradicts the results of Kennerknecht et al (1992), who considered this amount of fluid too small. Hanson et al (1992) reported that the volume of amniotic fluid removed does not appear to influence an adverse pregnancy outcome.…”

“…(1991) reported a 30 per cent culture failure. In the I1 weeks group, our results do not differ from the 78-91 per cent reported by Kennerknecht et al (1992) and Jorgensen et al (1992), and in the 10 weeks group, our 66 per cent culture success rate is also in the range of 55-94.7 per cent described by other authors (Nicolaides et al, 1994;Kennerknecht et al, 1992;Jorgensen et al, 1992).…”

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

“…An increased culture failure rate in 'early' amniotic fluids compared with those obtained later in pregnancy has been reported by several authors (Cederholm and Axelsson, 1997;Daniel et al, 1998;Kennerknecht et al, 1992;Nicolaides et al, 1996) while others have reported no difference (Fatemi et al, 1988;Crandall et al, 1994;Eiben et al, 1997). It is difficult to compare these studies with CEMAT because in some a relatively small proportion of fluids was obtained earlier than 13 weeks' gestation and in other cases the total number of fluids cultured was relatively small.…”

Evaluation of amniotic fluid cell filtration: An experimental approach to early amniocentesis

“…A bypass connected by two three-way taps easily allows AF cell filtration either during aspiration or during reinjection into the amniotic sac Penso and Frigoletto, 1990;Rebello et al, 1991;Djalali et al, 1992;Jorgensen et al, 1992;Kennerknecht et al, 1992b). Down to the 13th and most probably to the 12th week, the standard procedure known from 2 16th week amniocentesis is possible (Djalali er al., 1992;Kennerknecht et al, 1992b). However, with respect to eventual interruption after an abnormal finding, the time point for the less invasive evacuation and dilatation technique (i.e., 5 14th week) might be passed.…”