Fetal Loss Rate after Midtrimester Amniocentesis in Twin Pregnancies

Seo, Back Kyoung; Chung, Jin Hoon; Yang, Jae Hyug; Shin, Joong Sik; Kim, Moon Young; Ryu, Hyun Mee; Kim, Min Ji; Lee, Hyun Jung; Yu, Young; Choi, June Seek; Kim, Min Hyoung; Cho, Yeon Kyung; Choi, Kyu Hong

Abstract

OBJECTIVE
To assess the fetal loss rate among dichorionic twin gestations undergoing genetic amniocentesis compared with singletons undergoing the procedure and untested twins.
METHODS
From January 2002 through December 2004, total 132 pregnant women with dichorionic twin gestation with mid-trimester amniocentesis at Hospital were included in this study. In control group, 595 women with untested dichorionic twins during the same period and 402 women with singleton pregnancies with amniocentesis performed by the same physician at the same date of study group were selected. Excluded were fetuses with known structural anomalies, cases in which amniocentesis was done in only one fetus, and cases of which pregnancies were terminated due to fetal chromosomal abnormalities. Fetal loss was defined as the loss of both fetuses and subdivided into two categories: within 4 weeks after amniocentesis and before 28 gestational weeks.
RESULTS
Up to 4 weeks after the procedure, one case (0.75%) in the tested twin group, two cases in post-procedure singleton group (0.49%, P=.729), and eight cases in the untested twin control group (1.34%, P=.581) were aborted spontaneously. Up to 28 gestational weeks, four fetal losses occurred in post-amniocentesis twins (3.03%), sixteen cases in untested twins (2.69%, P=.83), and two cases in the singleton pregnancies with amniocentesis (0.49%, P=.017).
CONCLUSION
The risk of fetal loss in twin underwent mid-trimester amniocentesis appears to be higher than that of tested singletons in this study. However, there was no significant difference in the fetal loss rates between amniocentesis twin group and untested twin group.