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.

Patient's Choice between a Non-Invasive Prenatal Test and Invasive Prenatal Diagnosis Based on Test Accuracy

“…The procedure-related miscarriage in women with a positive screening test at three public hospitals in our locality providing universal screening was 0.7% (∼1 in 150) and similar to the 1% quoted to patients in our study. The 1% quoted to study participants was thus similar to what we empirically observed, but was still higher than the 1 in 200-300 quoted in professional guidelines [15,19]. …”

Patient's Choice between a Non-Invasive Prenatal Test and Invasive Prenatal Diagnosis Based on Test Accuracy

“…The procedure-related miscarriage in women with a positive screening test at three public hospitals in our locality providing universal screening was 0.7% (∼1 in 150) and similar to the 1% quoted to patients in our study. The 1% quoted to study participants was thus similar to what we empirically observed, but was still higher than the 1 in 200-300 quoted in professional guidelines [15,19]. …”

Acute Perinatal Infection and the Evidenced-Based Risk of Intrauterine Diagnostic Testing: A Structured Review

“…The total fetal risk related to amniocentesis in infected cohorts is estimated at 1.5%. This infected fetal loss rate is consistent with the noninfected "procedure only" fetal loss risk range of 0.11-0.35% added to the "background spontaneous" fetal loss risk of 0.7% for a total estimated risk of 1% [9][10][11][12][13][14][15][16][17][18][19]. The two most recent SRs/MAs have the "noninfected" procedure amniocentesis risk estimated at 0.30-0.35% [9,10].…”

Screening for chromosomal abnormalities using combined test in the first trimester of pregnancy

“…No miscarriages were reported. Complication rate in this study was lower than predicted, compared to a 0.5% to 1% abortion rate which was previously reported by other investigators [ 25 ].…”

Patient's Choice between a Non-Invasive Prenatal Test and Invasive Prenatal Diagnosis Based on Test Accuracy

“…The procedure-related miscarriage in women with a positive screening test at three public hospitals in our locality providing universal screening was 0.7% (∼1 in 150) and similar to the 1% quoted to patients in our study. The 1% quoted to study participants was thus similar to what we empirically observed, but was still higher than the 1 in 200-300 quoted in professional guidelines [15,19]. …”

Acute Perinatal Infection and the Evidenced-Based Risk of Intrauterine Diagnostic Testing: A Structured Review

“…The total fetal risk related to amniocentesis in infected cohorts is estimated at 1.5%. This infected fetal loss rate is consistent with the noninfected "procedure only" fetal loss risk range of 0.11-0.35% added to the "background spontaneous" fetal loss risk of 0.7% for a total estimated risk of 1% [9][10][11][12][13][14][15][16][17][18][19]. The two most recent SRs/MAs have the "noninfected" procedure amniocentesis risk estimated at 0.30-0.35% [9,10].…”

Screening for chromosomal abnormalities using combined test in the first trimester of pregnancy

“…No miscarriages were reported. Complication rate in this study was lower than predicted, compared to a 0.5% to 1% abortion rate which was previously reported by other investigators [ 25 ].…”

Patient's Choice between a Non-Invasive Prenatal Test and Invasive Prenatal Diagnosis Based on Test Accuracy

“…The procedure-related miscarriage in women with a positive screening test at three public hospitals in our locality providing universal screening was 0.7% (∼1 in 150) and similar to the 1% quoted to patients in our study. The 1% quoted to study participants was thus similar to what we empirically observed, but was still higher than the 1 in 200-300 quoted in professional guidelines [15,19]. …”

Acute Perinatal Infection and the Evidenced-Based Risk of Intrauterine Diagnostic Testing: A Structured Review

“…The total fetal risk related to amniocentesis in infected cohorts is estimated at 1.5%. This infected fetal loss rate is consistent with the noninfected "procedure only" fetal loss risk range of 0.11-0.35% added to the "background spontaneous" fetal loss risk of 0.7% for a total estimated risk of 1% [9][10][11][12][13][14][15][16][17][18][19]. The two most recent SRs/MAs have the "noninfected" procedure amniocentesis risk estimated at 0.30-0.35% [9,10].…”

Screening for chromosomal abnormalities using combined test in the first trimester of pregnancy

“…No miscarriages were reported. Complication rate in this study was lower than predicted, compared to a 0.5% to 1% abortion rate which was previously reported by other investigators [ 25 ].…”