Risk assessment of amniocentesis between 11 and 15 weeks: Comparison to later amniocentesis controls

Abstract

We studied 693 consecutive early amniocenteses (prior to 15 weeks) and found a spontaneous abortion rate to 28 weeks' gestation of 1.5 per cent. A control group of women having standard amniocentesis (15-20 weeks) experienced a 0.6 per cent fetal loss in the same period. There were no other apparent differences between the two groups. Early amniocentesis results are generally available 4-6 weeks before standard amniocentesis and 1-3 weeks after chorionic villus sampling (CVS). Alpha-fetoprotein (AFP) can be accurately assayed in 11- to 15-week amniotic fluid samples but additional studies are necessary to determine the accuracy of neural tube defect (NTD) detection. Including the present study, over 5800 early amniocenteses have been reported and the results suggest that this is a relatively safe prenatal diagnostic test and an alternative to CVS and later amniocentesis.

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.…”

The Early Amniocentesis Study: A Randomized Clinical Trial of Early Amniocentesis and Midtrimester Amniocentesis

“…Crandall et al [12] found no significant difference in congenital malformations detected at birth in patients having amniocentesis at less than 15 weeks compared to the controls at 15-20 weeks. The incidence of anomalies was 1.8 and 2.2%, respectively.…”

On the Complication Risk of Early Amniocentesis versus Standard Amniocentesis

“…The abortion rate up to week 28 of gestation found after first trimester CVS ranges between 5.6% [13], 4.9% [14], 3.4% [15] and 2.9% [16]. The EAC abortion rates in our study of 2.82% for week 11-12 up to week 28 and 1.82% for week 13-14 up to week 28 are lower or in the same range as the data reported from normal pregnancies without an invasive procedure or after CVS.…”