Vanishing twin is associated with less favorable obstetric outcome compared to singleton pregnancies in women undergoing IVF-ET

Abstract

COMPARED TO SINGLETON PREGNANCIES IN WOMEN UNDERGOING IVF-ET SONYA ABDEL-RAZEQ, MOHAMED MITWALLY, LAURA DETTI, MICHAEL SULLIVAN, KENT CRICKARD, MICHAEL DIAMOND, University at Buffalo, Gynecology and Obstetrics, Buffalo, New York, Wayne State University, Obstetrics and Gynecology, Bloomfield Hills, Michigan, Wayne State University, Department of Obstetrics and Gynecology, Detroit, Michigan, Wayne State University, Obstetrics/Gynecology, Detroit, Michigan OBJECTIVE: There is evidence that infertility treatment, including in vitro fertilization and embryo transfer (IVF-ET), is associated with less favorable obstetric outcome, specifically, higher pregnancy loss, preterm labor and low birth weight (BW). Vanishing-twin is a phenomenon in which one or more of implanted embryos fail to continue. We studied outcome of singleton pregnancies after vanishing-twin compared to pregnancies that started as singletons. STUDY DESIGN: Retrospective analysis of 61 consecutive live-births from singleton pregnancies in women undergoing IVF-ET. Five pregnancies started as twins and ended as singletons due to vanishing-twin; 56 pregnancies started as singletons. Vanishing-twin was diagnosed by ultrasound at 6-wks (2 gestational sacs with 2 heartbeats) followed by another ultrasound showing loss of one of the twins at 8 to 12 wks. Gestational age (GA) was calculated from ET day until delivery. BW was calculated as percentage from BW expected according to GA (expected BW was calculated from control population similar to Western New York region matching patients who underwent IVF-ET). RESULTS: Vanishing-twin pregnancies were associated with significantly lower BW and shorter GA. There was no significant difference regarding age, gravity, infertility factor and duration, ovarian stimulation protocol, or in vitro conditions (oocyte insemination, day and number of embryos transferred, fertilization or implantation rate). CONCLUSION: Pregnancies associated with vanishing-twin after IVF-ET are associated with higher risk for low BW and short GA.