409: Timing of intrauterine fetal demise (IUFD) following laser surgery for twin-twin transfusion syndrome (TTTS)

409 Timing of intrauterine fetal demise (IUFD) following laser surgery for twin-twin transfusion syndrome (TTTS) Brendan Grubbs, Lisa Korst, Arlyn Llanes, Marc Incerpi, Joseph Ouzounian, Ramen Chmait Keck School of Medicine, University of Southern California, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Los Angeles, CA OBJECTIVE: The purpose of this study was to describe the timing of post-operative IUFD following fetoscopic selective laser photocoagulation of communicating vessels (SLPCV) for TTTS, to allow for modification of counseling during the post-operative period. STUDY DESIGN: The study population included all SLPCV cases from 2006-2012. The minimum criterion for surgery was Quintero Stage 1 TTTS. Patients were observed for at least 24 hours, and discharged to their primary obstetrician when stable, with instructions for weekly evaluations over 4 weeks and then monthly follow-up. Outcomes were obtained from the primary obstetrician. IUFD rates following each milestone were calculated based on a denominator of patients meeting that milestone with both twins alive. RESULTS: Of 321 cases performed during the study period, 4 were excluded from analysis due to subsequent elective termination of pregnancy, for a final population of 317. Overall, there were 53 gestations with donor IUFD (16.7%), 24 with recipient IUFD (7.6%); of these, 12 had dual IUFD (3.8%). IUFD rates after each milestone are demonstrated in the Table. CONCLUSION: Following SLPCV for TTTS, at all milestones, IUFD predominantly involved the donor only. For all three IUFD scenarios, after 24 hours, the rate tended to decrease with time following surgery. This information can be used to modify patient counseling following SLPCV for TTTS. 410 Prospective risk of fetal death in gastroschisis Brian Shaffer, Amy Doss, Keenan Yanit, Yvonne Cheng, Alison Cahill, Jonathan Snowden, Aaron Caughey Oregon Health & Science University, Obstetrics & Gynecology, Portland, OR, University of California San Francisco, Obstetrics, Gynecology, & Reproductive Sciences, San Francisco, CA, Washington University, Obstetrics & Gynecology, St. Louis, MO OBJECTIVE: To evaluate the ongoing risk of intrauterine fetal demise (IUFD) in fetuses with gastroschisis compared to non-anomalous fetuses. STUDY DESIGN: A retrospective cohort study of all births in the United States in 2005-2006, as recorded in the National Center for Health Statistics natality database. We calculated the risk of IUFD in pregnancies with fetuses with gastroschisis as well as those categorized as non-anomalous. We utilized the number of at-risk fetuses as the denominator. We compared IUFD rates with the chi-square test and controlled for potential confounders with multivariable logistic regression analysis. RESULTS: The risk of IUFD in fetuses with gastroschisis was 4.5% overall as compared to 0.6% in the non-anomalous fetuses (p 0.001). In a multivariable analysis controlling for gestational age and other potential confounders, the adjusted odds ratio for IUFD in fetuses with gastroschisis was 5.94 (95% CI: 3.39-10.4). After 32 weeks, when examined by week of gestation, the risk of IUFD/ongoing pregnancy was greater at each week of gestation in fetuses with gastroschisis. (Table, Figure). CONCLUSION: The risk of IUFD for fetuses with gastroschisis is consistently greater than in non-anomalous fetuses. These data may be useful in decision making for timing of delivery for fetuses with gastroschisis.