Early amniocentesis: a cytogenetic evaluation.

Abstract

We investigated the use of amniocentesis performed at eight to 14 weeks' gestation as a possible alternative to chorionic villus sampling. Patients, methods, and results Samples of amniotic fluid were taken from 40 gestation, and the mean time to the cells being harvested was 12 6 days. In contrast only 17 (68%) of the 25 samples taken at eight to 11 weeks yielded a result. One sample taken at 13 weeks' gestation yielded a female karyotype, whereas the fetal parts revealed a male karyotype; the sample was subsequently identified as maternal urine. The mean volume of amniotic fluid obtained was 13 9 ml (range 1-40 ml). CommentAll 15 samples taken at 12-14 weeks' gestation yielded a result. The mean time to cells being harvested in this group (12-6 days) compared favourably with the current mean of 11 days for the samples obtained routinely at [16][17][18][19] weeks that are processed by our laboratory. Culture of all the 5 ml aliquots obtained at 12-14 weeks was successful. Thus a 10 ml sample would provide two cultures, which are necessary for the interpretation of equivocal results and in case of microbial infection.In one case, a urine sample was obtained at 13 weeks' gestation from an obese patient in whom imaging was poor. In a clinical environment sampling would not have been attempted, and this patient would have been recalled later.Our results show that amniocentesis from as early as 12 weeks' gestation can provide sufficient material for cytogenetic diagnosis and could be offered as an alternative to current methods of prenatal diagnosis. Furthermore, the procedure could be carried out by doctors already familiar with the technique, using existing resources. Patients must, however, be advised that the risks of this procedure are unknown. Preliminary reports from the United States suggest that early amniocentesis is safer than chorionic villus sampling.24 Further evaluation, preferably by means of a randomised trial, is urgently needed. We are continuing our investigation of amniocentesis before 12 weeks with the aim of bringing the procedure forward into the first trimester of pregnancy.We acknowledge contributions to the study from Mr N Fisk, Mr P Reginald, Mr M Michel, and Mrs R Rebello.

Amniocentesis before 14 completed weeks as an alternative to transabdominal chorionic villus sampling: a controlled trial with infant follow‐up

“…Since 1987, several uncontrolled series of early amniocentesis have been published (Miller et al, 1987;Godmilow et al, 1988;Cuoco et al, 1989;Evans et al, 1988Evans et al, , 1989Lituania et al, 1989;Richkind and Aleck, 1989;Rooney et al, 1989;Stripparo et al, 1989;Blache et al, 1990;Elejalde et al, 1990;Klapp et al, 1990;Lindner et al, 1990;Nevin et al, 1990;Penso et al, 1990;Stripparo et al, 1990;Thayer et al, 1990;Grujic et al, 1991;Hackett et al, 1991;Rebello et al, 1991;Assel et al, 1992;Bombard and Rigdon, 1992;Djalali et al, 1992;Hanson et al, 1992;Henry and Miller, 1992;Jorgensen et al, 1992;Gabriel et al, 1993;Huter et al, 1993;Kerber and Held, 1993;Eiben et al, 1994). When combined, these studies relate to results of EA in well over 10 000 women.…”

Early Filtration Amniocentesis for Further Investigation of Mosaicism Diagnosed by Chorionic Villus Sampling

“…A comparison of different studies of early amniocentesis has so far not revealed major differences in spontaneous fetal losses when compared with later gestations (Sundberg et al, 1995b). But culture failure rates are increased in the early weeks (Elajalde et al, 1990;Byrne et al, 1991;Thayer et al, 1990;Rooney et al, 1989;Nicolaides et al, 1996), which makes this approach less acceptable as a follow-up procedure.…”

“…However, several studies have reported higher culture failure rates when sampling amniotic fluid prior to week 14, which makes early amniocentesis with the conventional technique a less attractive approach as a follow-up procedure (Elejalde et al, 1990;Byrne et al, 1991;Thayer et al, 1990;Rooney et al, 1989). This is probably due to a lower cell concentration in the amniotic fluid during these earlier weeks (Elejalde et al, 1990).…”

Early Amniocentesis at 10–12 Weeks' Gestation

“…Most authors agree that with amniocentesis from the 13th week onwards, enough material can be obtained, and it is a safe procedure and gives reasonably good results (Rebello et aI., 1991;Djalali et al, 1992). It is a clear alternative to CVS as a prenatal diagnosis procedure, but it is still a controversial issue with respect to previous gestations (Rebello et al, 1991;Rooney et al, 1989;Jorgensen et al, 1993).…”

“…For 10-12 weeks it has been estimated in 8-21 days Eiben et al, 1994;Jorgensen et al, 1992;Hanson et al, 1992;Kerber and Held, 1993;Rebello et al, 1991;Mediano et al, 1992;Rooney et al, 1989).…”