Chorionic Villus Sampling and Marked Membrane Separation

Background/ The major concern about the invasive prenatal diagnostic tests is the frequency of procedure induced pregnancy loss. Chorionic Villus Sampling (CVS) is the invasive test of choice in the first trimester after the 10th gestational week. Our experience suggests marked chorioamniotic separation is an uncommon finding after the 10th gestational week. This study assesses the rate of marked membrane separation in a 10 to 14-week gestational period and its effect on post CVS fetal loss.Patients and Forty-one patients (5.2%) were selected among 782 patients as cases with marked membrane separation (mean maternal age, 26.9 years). CVS procedures were performed with a 20-gauge Chiba needle attached to a 20-ml syringe under ultrasound guidance. Follow-up was performed by phone call and clinical visits until 24 weeks of gestation. For the control group, the follow-up was performed for only 2 weeks. Early fetal loss in the first two weeks of post procedural period, and late fetal loss from 2 weeks after procedure till the 24th gestational week were considered as CVS complications. We detected 2.4% early fetal losses after the procedure. Fourteen cases voluntarily underwent therapeutic abortion due to beta-thalassemia or hemophilia. One fetus with microcephaly was spontaneously aborted in the 21st gestational week. Twenty-five neonates were delivered alive at term and one prematurely at the 32nd week. Marked membrane separation had no significant effect on early post CVS fetal loss rate. The procedure does not have a major impact on the early post CVS fetal loss in patients with marked membrane separation.