Amniocentesis and chorionic villus sampling for prenatal diagnosis

Abstract

Background A major disadvantage of second trimester amniocentesis is that the results are available relatively late in pregnancy (after 16 weeks’ gestation). Chorionic villus sampling (CVS) and early amniocentesis can be done in the first trimester of pregnancy and offer an earlier alternative. Objectives To assess comparative safety and accuracy of second trimester amniocentesis, early amniocentesis, transcervical and transabdominal CVS. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (January 2008). Selection criteria All randomised trials comparing amniocentesis and CVS by either transabdominal or transcervical route. Data collection and analysis Two review authors independently assessed eligibility and trial quality and performed data extraction. Main results We included a total of 16 randomised studies. One study in a low-risk population (N = 4606) with a background pregnancy loss of around 2% found that a second trimester amniocentesis will increase total pregnancy loss by another 1%. This difference did not reach statistical significance and the confidence intervals (CI) around this excess risk were relatively large (risk ratio (RR) 1.41; 95% CI 0.99 to 2.00). In the same study, compared with no intervention, the increase in spontaneous miscarriages following second trimester amniocentesis was statistically significant (2.1% versus 1.3%; RR 1.60; 95% CI 1.02 to 2.52). Early amniocentesis is not a safe early alternative to second trimester amniocentesis because of increased pregnancy loss (7.6% versus 5.9%; RR 1.29; 95% CI 1.03 to 1.61) and higher incidence of talipes compared to CVS (RR 4.61; 95% CI 1.82 to 11.66). Compared with a second trimester amniocentesis, transcervical CVS carries a higher risk of pregnancy loss, although the results are quite heterogeneous. One study compared transabdominal CVS with second trimester amniocentesis and found no significant difference in the total pregnancy loss between the two procedures. Transcervical CVS is more technically demanding than transabdominal CVS, with more failures to obtain sample and more multiple insertions. However, the results related to comparative pregnancy loss between transabdominal and transcervical CVS are inconclusive, with significant heterogeneity between studies. Authors’ conclusions Second trimester amniocentesis is safer than early amniocentesis or transcervical CVS, and is the procedure of choice for second trimester testing. Transabdominal CVS should be regarded as the procedure of first choice when testing is done before 15 weeks’ gestation. Diagnostic accuracy of different methods could not be assessed adequately because of incomplete karyotype data in most studies.

Amniocentesis is a safe and effective prenatal diagnostic tool: a clinical study in Eastern India

“…5 This study, a gold standard study in the field of fetal medicine, provides the best estimate of an excess pregnancy loss in low-risk women caused by amniocentesis. 16 This study reported the amniocentesis procedure related risk of miscarriage in the study group was an additional 1% over the control group. Concerns were raised about the unexpectedly low background loss rate in the nonamniocentesis group in this study.…”

Analysis of results of genetic amniocentesis in a private center

“…Como es una prueba invasiva, la misma no está exenta de peligros y conlleva un riesgo de perdida fetal de aproximadamente el 0,5% cuando se realiza en el segundo trimestre, después de la fusión de la membrana amniótica con el corion (40). El riesgo de aborto asociado a la amniocentesis se calcula en 0,25 -0,50% (¡Error!…”

Next generation sequencing of SNPs for non-invasive prenatal diagnosis: challenges and feasibility as illustrated by an application to β-thalassaemia

“…1 Currently, fetal genetic material for prenatal diagnosis is sampled by invasive procedures, which are associated with a significant risk of induced abortion. 2,3 The discovery that during pregnancy there is a median of 10% of cell-free fetal DNA in the maternal circulation opened up new avenues in the diagnostics of fetal genetics. [4][5][6] However, this poses a technical challenge as fetal DNA represents a minor population in maternal plasma, exacerbated by the fragmentation of fetal DNA.…”