Tehran University Medical Journal

Background: Chorionic villus sampling refers to a procedure in which small samples of placenta are obtained for prenatal genetic diagnosis, generally in the first trimester of pregnancy in 11 weeks till 13 weeks+6 days. This procedure provides prenatal diagnosis in pregnancy. Amniocentesis is a technique for windrowing amniotic fluid from the uterine cavity using a needle via a trans abdominal approach. Amniocentesis and chorionic villus sampling are invasive prenatal procedure. Their complications are fetal loss vaginal bleeding, rupture of membrane chorioamnionitis and limb reduction. There are some probable predictors of fetal loss after chorionic villus sampling and amniocentesis including maternal age, gestational age, number of needle insertion, previous miscarriage, and placental location. The aim of this study was to compare procedure related complications of amniocentesis and chorionic villus sampling in a tertiary referral hospital in Iran.

Methods: This retrospective cohort study was done in pregnant women who were high risk in genetic screening tests. The pregnancy outcome of women who underwent amniocenthesis and chorionic villus sampling was assessed in Yas Women General Hospital (Mirza Kuchak Khan), Tehran, Iran, from 2001 to 2011. Group one, pregnant women who underwent amniocentesis, was compared with group two, pregnant women that underwent chorionic villus sampling. The statistical analyses were performed with SPSSv.20 using a significant level of α<0.05.

Results: There were no significant differences between the two groups in procedure related fetal loss before 24th weeks of pregnancy (1.1% in chorionic villus sampling group versus 0.6% in amniocentesis group, P=0.318). A significant relationship between the number of needle insertion in the chorionic villus sampling group and fetal loss before 24th weeks of pregnancy was seen P<0.028. There were no significant differences between the two groups in the occurrence of vaginal bleeding, rupture of membrane, pre-term birth, placenta location, low birth weight and very low birth weight. The risk of chorioamnionitis was higher in chorionic villus sampling group (P=0.019). No significant difference was observed between the liquid and bloody amniotic fluid and pregnancy complications.

Conclusion: There was no significant difference between the procedure related complications of amniocentesis and chorionic villus sampling.