title: [Transfer of single embryo as a method to reduce twins pregnancy rate in in-vitro fertilization treatment].
abstract: BACKGROUND
  The high success rate in IVF treatments is followed by a high rate of multiple pregnancies. Over 30% of IVF pregnancies are multiples and carrying higher risk to the neonates compared with singleton pregnancy. Twin pregnancy is less dangerous then high order multiple pregnancy but it has a significantly higher risk factor compared with singleton pregnancy. Therefore, it is crucial to find methods to reduce twin pregnancy rate. The goal of this review is to present the peril of twin pregnancy and to evaluate the alternative of selective single embryo transfer (SET) in order to reduce the rate of multiple pregnancies in IVF.
  
  
  METHODS
  Survey of the literature on SET.
  
  
  RESULTS
  Patients with high pregnancy rate bear higher risk for multiple pregnancy. In these cases transfer of single high quality embryo can result in a pregnancy rate of over 30% without the risk of multiple pregnancies. Selective SET may lead to a significant decrease in multiple pregnancies rate with only a slight drop in the general pregnancy rate.
  
  
  CONCLUSIONS
  Selective SET in patients with elevated chance to conceive may result in good pregnancy rate without the risk of multiple pregnancy.
authors.affiliation: In-vitro Fertilization Unit, Department of Obstetrics and Gynecology, University Hospital Hadassah-Har-Hatzofim, Jerusalem.
authors.forename: Amir
authors.initials: A
authors.lastname: Ravhon
authors.forename: Arye
authors.initials: A
authors.lastname: Hurwitz
mesh_terms: D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D011247:Pregnancy; D018607:Pregnancy Reduction, Multifetal; D011272:Pregnancy, Multiple