Selective termination in dichorionic twins discordant for congenital defect Eugenia Antolı ´n Alvarado *, Ricardo Pe ´ rez Ferna ´ ndez Pacheco, Francisco Ga ´ mez Alderete, Jua ´n Antonio de Leo ´n Luı ´s, A ´ ngel Aguaro ´n de la Cruz, Luı ´s Ortiz Quintana Department of Obstetrics and Gynecology, Fetal Medicine Unit, Hospital General Universitario Gregorio Maran ˜o ´n, Universidad Complutense de Madrid, Madrid, Spain 1. Introduction Over the past three decades, advanced maternal age and improvement in assisted reproductive techniques have resulted in an exponential increase of twin pregnancies. Overall, the risk of congenital defects is higher in twins than in singletons. In dizygotic (DZ) twins, the incidence of structural anomalies is similar to that of singletons, while in monozygotic (MZ) pregnancies the risk is two to three times higher [1]. In both MZ and DZ twins, in nearly 85% of cases the malformation is confined to one fetus and the co- twin is normal. With regard to chromosomal abnormalities, DZ twins are supposed to have twice the risk per pregnancy, as the risk for each fetus is independent, but some conflicting results exist [2,3]. In MZ pregnancies, both fetuses should be genetically identical and the risk of chromosomal defect similar to singletons, but cases of heterokaryotypia have been reported. Genetic counseling in twins is difficult [4,5]. Screening strategies using biochemical, ultrasonographic or combined tests have limitations [6–9]. So, before twins are screened, and especially before a prenatal invasive test, parents should be informed about the possible implications of discordant results and the available options [1–3,6,9–11], which include expectant management, termination of the whole pregnancy (TOP) or selective termination (ST). Selective termination of the affected fetus is uniformly accepted in severe congenital defects, but still controversial when lethal anomalies exist [1,12]. The main variable in selecting the technique of ST is chorionicity. In dichorionic (DC) twins, intracardiac injection of KCl in the affected fetus until asystole asystolia is safe for the normal co-twin, as vascular communications do not exist. In monochorionic (MC) pregnancies, the risk of passage of KCl into the circulation of the normal co-twin through placental anasto- mosis precludes this technique [13]. In this paper, we report the perinatal outcome of ST in DC twins discordant for congenital defect, performed at the Hospital General Universitario Gregorio Maran ˜on by means of intracardiac injection of KCl in the affected fetus. 2. Material and methods A total of 28 ST in DC twins discordant for congenital defect performed from May 2008 to February 2011 at the Hospital General Universitario Gregorio Maran ˜on were analyzed. Parents European Journal of Obstetrics & Gynecology and Reproductive Biology 161 (2012) 8–11 A R T I C L E I N F O Article history: Received 23 March 2011 Received in revised form 20 September 2011 Accepted 13 November 2011 Keywords: Selective termination Dichorionic twins Discordant congenital defect A B S T R A C T Objective: To evaluate the perinatal outcome of selective termination in dichorionic twins discordant for congenital defect, performed at the Hospital General Universitario Gregorio Maran ˜ on. Study design: Twenty-eight dichorionic twins with an anomalous fetus were included from May 2008 to February 2011. Intracardiac KCl (1–2 ml; 15 mEq/ml) under ultrasonographic guidance was used in all procedures. Congenital defect, gestational age at the procedure, incidence and perinatal outcome were retrieved. Results: Selective termination was performed in 14 (50%) cases of structural defects with normal karyotype and in 14 (50%) cases of chromosomal abnormality, 13 of them (92.8%) trisomy 21. Median gestational age at the procedure was 17.8 weeks (range 14.5–24; SD 2.3), and 12 (42.8%) were performed before 18 weeks. The presenting fetus was terminated in 11 cases (39.3%). Selective termination was followed by the subsequent delivery of a viable infant in 27 out of 28 cases (96.4%). Fetal loss before 24 weeks occurred in 1 case (3.6%). Median gestational age at delivery was 38 weeks (range 24.1–40.1; SD 3.8). Twenty-four (88.9%) were delivered >34 weeks and 1 (3.7%) before 28 weeks. Conclusion: Selective termination in dichorionic twins discordant for congenital defect is a safe procedure with low risk of unintended fetal loss. This option is a reasonable alternative to expectant management or termination of the whole pregnancy. ß 2011 Elsevier Ireland Ltd. All rights reserved. * Corresponding author at: Departamento de Obstetricia y Ginecologı ´a, Hospital General Universitario Gregorio Maran ˜o ´ n, O’Donnell 48-50, 28009 Madrid, Spain. Tel.: +34 91 529 02 18. E-mail addresses: eantolin.hgugm@salud.madrid.org, eugenia-antolin@terra.es (E.A. Alvarado). Contents lists available at SciVerse ScienceDirect European Journal of Obstetrics & Gynecology and Reproductive Biology jou r nal h o mep ag e: w ww .elsevier .co m /loc ate/ejo g rb 0301-2115/$ – see front matter ß 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejogrb.2011.11.024