{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T05:38:14Z","timestamp":1791437894114,"version":"4.3.3"},"reference-count":32,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2012,7,13]],"date-time":"2012-07-13T00:00:00Z","timestamp":1342137600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Ultrasound in Obstet &amp; Gyne"],"published-print":{"date-parts":[[2012,8]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Objective<\/jats:title><jats:p>To review the available evidence regarding pregnancy loss following first\u2010trimester chorionic villus sampling (CVS) and mid\u2010trimester genetic amniocentesis in twins.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>We searched the MEDLINE database from January 1990 to May 2011 for randomized and cohort studies reporting on the risk of pregnancy loss after first\u2010trimester CVS performed between 9 and 14 weeks and after genetic amniocentesis performed between 14 and 22 weeks. Where appropriate, we calculated pooled proportions and relative risks with 95% CI.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>No randomized studies were found. For CVS, nine studies fulfilled the inclusion criteria. The overall pregnancy\u2010loss rate was 3.84% (95% CI, 2.48\u20135.47; <jats:italic>n<\/jats:italic> = 4). The rate of pregnancy loss before 20 weeks was 2.75% (95% CI, 1.28\u20134.75; <jats:italic>n<\/jats:italic> = 3) and before 28 weeks was 3.44% (95% CI, 1.67\u20135.81; <jats:italic>n<\/jats:italic> = 3). For amniocentesis, the overall pregnancy\u2010loss rate was 3.07% (95% CI, 1.83\u20134.61; <jats:italic>n<\/jats:italic> = 4). The rate of pregnancy loss before 20 weeks was 2.25% (95% CI, 1.23\u20133.57; <jats:italic>n<\/jats:italic> = 2), before 24 weeks was 2.54% (95% CI, 1.43\u20133.96; <jats:italic>n<\/jats:italic> = 9) and before 28 weeks was 1.70% (95% CI, 0.37\u20133.97; <jats:italic>n<\/jats:italic> = 5). Pooled data from four case\u2013control studies showed a higher risk (2.59% vs. 1.53%) of pregnancy loss before 24 weeks following amniocentesis (relative risk = 1.81; 95% CI, 1.02\u20133.19). There were no statistically significant differences in reported pregnancy loss between transabdominal and transcervical approaches, use of a single\u2010needle system vs. a double\u2010needle system and single uterine entry vs. double uterine entry in the CVS group. Similarly, in the amniocentesis group, there was no statistically significant difference in fetal loss between the single uterine entry vs. the double uterine entry.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>In the absence of randomized studies, it is not possible to estimate accurately the excess risk following invasive procedures in twins. Currently available data show similar overall pregnancy\u2010loss rates for both amniocentesis and CVS with the excess risk of around 1% above the background risk. Copyright \u00a9 2012 ISUOG. Published by John Wiley &amp; Sons, Ltd.<\/jats:p><\/jats:sec>","DOI":"10.1002\/uog.10152","type":"journal-article","created":{"date-parts":[[2011,11,28]],"date-time":"2011-11-28T18:23:47Z","timestamp":1322504627000},"page":"128-134","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":113,"title":["Pregnancy loss after chorionic villus sampling and genetic amniocentesis in twin pregnancies: a systematic review"],"prefix":"10.1002","volume":"40","author":[{"given":"K.","family":"Agarwal","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Z.","family":"Alfirevic","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2012,7,13]]},"reference":[{"key":"e_1_2_5_2_2","first-page":"CD003252","article-title":"Amniocentesis and chorionic villus sampling for prenatal diagnosis","author":"Alfirevic Z","year":"2003","journal-title":"Cochrane Database Syst Rev"},{"key":"e_1_2_5_3_2","doi-asserted-by":"publisher","DOI":"10.1097\/01.AOG.0000278820.54029.e3"},{"key":"e_1_2_5_4_2","volume-title":"Green\u2010top guideline No. 8","year":"2010"},{"key":"e_1_2_5_5_2","unstructured":"Screening for fetal chromosomal abnormalities. 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