Amy L Harris1, Caitlin R Sacha, Kristen M Basnet, Kaitlyn E James, Taylor S Freret, Anjali J Kaimal, John Yeh, Irene Souter, Drucilla J Roberts, Thomas L Toth. 1. Massachusetts General Hospital Fertility Center and Harvard Medical School, Boston, Massachusetts; the Department of Women's Health, Wright Patterson Air Force Base, Wright Patterson AFB, and the Department of Obstetrics & Gynecology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio; the Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts; CellNetix Pathology and Laboratories and Swedish Medical Center, Seattle, Washington; and the Deborah Kelly Center for Outcomes Research, the Division of Maternal Fetal Medicine, Department of Obstetrics & Gynecology, and the Department of Obstetrics & Gynecology, Massachusetts General Hospital, Boston, Reproductive Endocrinology/Infertility, Department of Obstetrics & Gynecology, UMass Memorial Medical Center, Worcester, Boston IVF, Waltham, and the Department of Obstetrics & Gynecology, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
Abstract
OBJECTIVE: To characterize the obstetric outcomes and placental pathology in live births arising from vanishing twin pregnancies compared with nonreduced in vitro fertilization (IVF) pregnancies. METHODS: This is a retrospective cohort study of live births resulting from fresh embryo transfers after IVF cycles with autologous oocytes from 2004 through 2017 at a large academic fertility center. Clinical information and pathology reports were reviewed. Placental diagnoses were coded using established nosology by expert placental pathologists. Analysis of variance, Kruskal-Wallis, Pearson's χ, and Fisher exact tests were used, as appropriate, to compare pathology categories between pregnancy outcomes. Mixed effects logistic regression models were generated to reveal the association between pregnancy outcome and placenta pathology, controlling for pregnancies arising in the same woman and various suspected confounders. RESULTS: Of 905 fresh autologous IVF cycles with placental pathology available for review, we identified 73 vanishing twin pregnancies (8.1%), 556 singleton pregnancies (61.4%), and 276 twin pregnancies (30.5%). Vanishing twin syndrome was not associated with preterm delivery, route of delivery, growth restriction or other obstetric outcomes as compared with IVF singleton pregnancies. However, vanishing twin syndrome pregnancies showed distinctive placental pathologies including an increased rate of small placentas (less than the 10th percentile by weight), with more anatomical abnormalities than IVF singleton pregnancies (odds ratio 1.73, 95% CI 0.94-3.19; adjusted odds ratio 2.15, 95% CI 1.08-4.28). The frequency of placental vascular and inflammatory pathologies associated with IVF vanishing twin syndrome pregnancies were similar to that of IVF singleton pregnancies. Loss of a twin after 8 weeks of gestation was not associated with greater risks of placental pathologies. CONCLUSION: In vitro fertilization pregnancies affected by vanishing twin syndrome did not have significant differences in obstetric or perinatal outcomes as compared with twin or singleton gestations. However, early twin loss was potentially associated with differences in placental development associated with a higher rate of small placentas and other anatomic pathologies.
OBJECTIVE: To characterize the obstetric outcomes and placental pathology in live births arising from vanishing twin pregnancies compared with nonreduced in vitro fertilization (IVF) pregnancies. METHODS: This is a retrospective cohort study of live births resulting from fresh embryo transfers after IVF cycles with autologous oocytes from 2004 through 2017 at a large academic fertility center. Clinical information and pathology reports were reviewed. Placental diagnoses were coded using established nosology by expert placental pathologists. Analysis of variance, Kruskal-Wallis, Pearson's χ, and Fisher exact tests were used, as appropriate, to compare pathology categories between pregnancy outcomes. Mixed effects logistic regression models were generated to reveal the association between pregnancy outcome and placenta pathology, controlling for pregnancies arising in the same woman and various suspected confounders. RESULTS: Of 905 fresh autologous IVF cycles with placental pathology available for review, we identified 73 vanishing twin pregnancies (8.1%), 556 singleton pregnancies (61.4%), and 276 twin pregnancies (30.5%). Vanishing twin syndrome was not associated with preterm delivery, route of delivery, growth restriction or other obstetric outcomes as compared with IVF singleton pregnancies. However, vanishing twin syndrome pregnancies showed distinctive placental pathologies including an increased rate of small placentas (less than the 10th percentile by weight), with more anatomical abnormalities than IVF singleton pregnancies (odds ratio 1.73, 95% CI 0.94-3.19; adjusted odds ratio 2.15, 95% CI 1.08-4.28). The frequency of placental vascular and inflammatory pathologies associated with IVF vanishing twin syndrome pregnancies were similar to that of IVF singleton pregnancies. Loss of a twin after 8 weeks of gestation was not associated with greater risks of placental pathologies. CONCLUSION: In vitro fertilization pregnancies affected by vanishing twin syndrome did not have significant differences in obstetric or perinatal outcomes as compared with twin or singleton gestations. However, early twin loss was potentially associated with differences in placental development associated with a higher rate of small placentas and other anatomic pathologies.