Genetic diagnosis by chorionic villus sampling before 8 gestational weeks: Efficiency, reliability, and risks on 317 completed pregnancies

Abstract

Transabdominal chorionic villus sampling (TA-CVS) was attempted in 328 high-risk pregnancies at 6-7 weeks of gestation. Sampling was feasible in 97.7 per cent of cases; chorionic tissue specimens of more than 10 mg were obtained in 94.4 per cent of cases at the first needle insertion and in 100 per cent after a second attempt. Fetal karyotyping succeeded in 99.4 per cent of cases, while no diagnostic failures were reported in enzymatic and DNA analyses. Fetal loss rate in the first 4 weeks after CVS was significantly higher than in the later CVS series (7.2 vs. 2.5 per cent), but 50 per cent of losses were observed within 2 weeks in cases of inviable aneuploidies. A high incidence of severe limb abnormalities (1.6 per cent) was detected in pregnancies intended to continue, confirming the aetiological role of early CVS. Unclear visualization of the placental limits and poor control of the needle path are thought to be the main reasons for the vascular disruption of the chorionic plate, and thereby hypoxic embryo tissue damage. A better selection of cases, together with high-resolution vaginal ultrasound visualization, and analytical techniques requiring a minimal amount of tissue should avoid any teratogenic effect of early CVS.

Increased Incidence of Preeclampsia in Pregnancies Complicated by Fetal Malformation

“…The possible role of impaired perfusion in the development of a malformation is supported by the fol lowing consideration. Although the safety of chorionic vil lous sampling (CVS) in the hands of expert clinicians is not questioned, its association with an increased inci dence of malformation is still a matter of controversy [11][12][13][14][16][17][18], A recent large collaborative study denied any correlation with limb reduction defects [17], though it leaves open the question of cases performed before the 9th week. Indeed an incidence of severe limb abnormalities as high as 1.6% following CVS before the 8th week has been reported [11], These defects have been interpreted as a result of fetal hemorrhage due to vascular disruption, or the release of vasoactive peptides and other damage to the uteroplacental circulation.…”

“…Although the safety of chorionic vil lous sampling (CVS) in the hands of expert clinicians is not questioned, its association with an increased inci dence of malformation is still a matter of controversy [11][12][13][14][16][17][18], A recent large collaborative study denied any correlation with limb reduction defects [17], though it leaves open the question of cases performed before the 9th week. Indeed an incidence of severe limb abnormalities as high as 1.6% following CVS before the 8th week has been reported [11], These defects have been interpreted as a result of fetal hemorrhage due to vascular disruption, or the release of vasoactive peptides and other damage to the uteroplacental circulation. Accordingly ecchymotic le sions in the human fetus during CVS have been directly observed by means of embryoscopy [19], Moreover tem porary clamping of uterine vessels in pregnant rats results in a dramatic increase in the diameter of the vessels in the nose, limbs, tail and genital tubercle, with hemorrhage, necrosis and consequent reabsorption of the preexisting structures [20].…”

Intrauterine Diagnosis of Genodermatoses

“…However, earlier reports suggested a higher rate of limb defects with lower gestational age [19,20], an association that was later refuted [21]. Nevertheless, most centers prefer to delay CVS until after the 10th week of gestation [17].…”

Detection of short tandem repeats at 5 loci and amelogenin with cell-free fetal DNA as a specimen in the development of prenatal paternity diagnostic tests

“…Amniocentesis carries a 1 in 300 to 1 in 500 risk of miscarriage and very limited risk of other complications (Seeds 2004;Elchalal et al 2004). Chorionic villus sampling carries a similar risk of miscarriage and a 1 in 3000 risk of fetal limb reduction defects, especially when performed within the first 10 weeks of gestation (Brambati et al 1992). Due to this risk, a non-invasive method of carrying out prenatal paternity tests has been developed.…”