Complete follow-up in assessing fetal losses after chorion villus sampling

Limb anomalies following chorionic villus sampling: a registry based case-control study

Using data from the Italian Multicentric Birth Defect Registry a case-control study was performed to verify if chorionic villus sampling (CVS) was associated with transverse limb defects (TLD), with or without features of oro-mandibular-limb hypogenesis complex (OMLHC), in the exposed offspring. The results show that the risk of TLD and OMLHC is increased following CVS, and is particularly high for CVS performed early in pregnancy, i.e., under 70 days of gestational age. These results, together with a review of other epidemiologic studies, biological data and clinical reports, strongly suggest a causative role of CVS as a risk factor for TLD and indicate that at this stage CVS before 70 days of gestational age should be discouraged as an option for prenatal diagnosis and that all patients wishing to undergo CVS should be informed about the possible risk of the procedure.

Importance of complete follow-up of spontaneous fetal loss after amniocentesis and chorion villus sampling

Women who are the most difficult to trace after amniocentesis or chorion villus sampling are often those who have had an adverse pregnancy outcome. To calculate total fetal loss figures for use in prenatal counselling we have followed in a multicentre study 100% of women who had undergone these procedures. Early spontaneous loss (within three weeks of the procedure) and total spontaneous loss were much lower after amniocentesis (0.2% and 1.3%, respectively) than after chorion villus sampling (1.2% and 2.9%). Four spontaneous fetal losses among the 20 pregnancies that were the most difficult to follow-up increased the loss rate by 0.5% for chorion villus sampling. Risk of early fetal loss after chorion villus sampling was related to experience of the operator (relative risk [RR] 4.3, p = 0.003), and total fetal loss was lower in pregnancies tested at 10 weeks' or more gestational age compared with those tested before 10 weeks' (RR 0.4, p = 0.01). A table showing the frequency of each of the seven possible outcomes after amniocentesis and chorion villus sampling is useful in counselling those considering one or other test.

Transabdominal chorion villus sampling: a safe and reliable procedure

A complete follow-up of the first 578 patients undergoing transabdominal chorion villus sampling (TACVS) in our combined practices was undertaken to determine the pregnancy loss rate. Factors contributing to losses and the problems incurred in achieving a clinically relevant result were also examined. It was found that increasing experience led to fewer procedural difficulties but that there persisted a higher problem rate in those women with a retroverted uterus. In 98.1% of patients an adequate volume of tissue was obtained and in 95.5% a clinically relevant result was achieved. This second figure rose to 96.3% in the latter part of the study. There was a total fetal loss rate of 2%, with only 0.5% (3 patients) having a missed abortion within 4 weeks of the procedure. It is concluded that TACVS is a reliable procedure with a high level of safety.