Safety and fetal outcome of early and midtrimester amniocentesis

A Proof-of-Concept Case Study for Personalized Noninvasive Prenatal Diagnosis: Can We Put It to Work?

This commentary highlights the article by van den Oever et al that describes a new method of prenatal diagnosis of single-mutation disorders.

Early second trimester (13 to 20 weeks) transabdominal chorionic villus sampling (TA-CVS): a safe and alternative method for both high and low risk populations

OBJECTIVE

To assess feasibility, effectiveness and risk of prenatal diagnosis by TA-CVS at 13-14 and 15-20 weeks' gestation.

METHODS

CVS was performed transabdominally by free-hand single needle insertion technique under continuous ultrasound visualization on 1844 pregnant women, aged 18 to 48, at 13 to 20 weeks' gestation, whose primary indication was chromosomal anomalies and single gene defects in 85% and 15% of cases, respectively Clinical follow-up of women undergoing TA-CVS at 13 to 20 weeks' was prospectively obtained; the population was split in two groups of 13-14 (series B) and 15-20 weeks' (series C) gestation. Statistical evaluation included a group of TA-CVS cases performed at 11-12 weeks (series A).

RESULTS

Sampling was feasible in 98.2%, 99.1% and 95.8% of cases of series A, B and C, respectively. Sampling was successful in all cases of the three series and a second insertion was required in 1.5%, 1.3% and 0.9%, respectively. A trend towards lower fetal loss rate is apparent (1.02%, 0.86%, and 0.46 in series A, B, and C, respectively), although differences were not statistically significant. No post-procedural complications were reported for series B and C, while spotting was present in 1.8% of cases for series A. Karyotyping was totally successful by short term culture and was also available by long term culture in 99% of cases for series A, B and C when the amount of chorionic tissue was more than 15 mg.

CONCLUSION

TA-CVS appears highly effective and safe and might be offered as a valuable alternative to early as well as mid-trimester amniocentesis.

Clinical proceduress in prenatal diagnosis

The prenatal diagnosis of fetal genetic disease has become a routine part of obstetric care. Pregnancies at risk are identified by a number of factors, including maternal age, positive serum screening, a history of a previous affected child, a parental chromosome rearrangement or an ultrasound-identified anomaly. Invasive diagnostic testing can be performed in the first trimester by chorionic villus sampling or in the second trimester by amniocentesis. Both procedures are safe, with an equivalent 0.5% risk of procedure-induced pregnancy loss. When performed prior to the routine sampling window of 15 weeks, amniocentesis may increase the risk of talipes equinovarus, the highest risk being encountered prior to 13 weeks' gestation. When chorionic villus sampling is performed prior to 9 weeks' gestation, there may be an increased risk of limb reduction defects. The laboratory analysis of both procedures is reliable. Chorionic villus sampling has a 1-2% incidence of confined placental mosaicism, requiring additional evaluation in some cases.