This pregnancy went on as a singleton pregnancy, and ended in live birth of a healthy fetus at a gestational age of 33 weeks. It was first described in 1978 by Alberg, who performed intracardiac puncture of the fetal heart of a fetus affected by Hurler's syndrome ( Alberg et al., 1978). Pregnancy reduction from twin to singleton is not as commonly accepted as reduction of triplets and higher orders multiples is. Other reasons for fetal reduction in women with a dichorionic twin pregnancy could be to reduce obstetric risks associated with a multiple pregnancy or electively for social indications. In this situation, selective feticide of fetuses with major or lethal abnormalities might be considered. Consequently, more women are faced with the circumstances of a twin pregnancy with one abnormal fetus. Due to the rapid and ongoing advancements in prenatal diagnosis and screening ( Avni et al., 2007 Benn et al., 2013), structural and chromosomal abnormalities are diagnosed more often, and at earlier gestation.

In the USA, multiple pregnancies account for 15–20% of all preterm births, consequently increasing the perinatal morbidity and mortality rates ( Goldenberg et al., 2008) and associated costs.Ĭompared with women with a singleton pregnancy, women with a twin pregnancy have a doubled chance of carrying one fetus with a chromosomal or structural abnormality ( Evans et al., 1999). Although the number of women with a twin pregnancy is currently declining, mainly due to a policy of single embryo transfer in in vitro fertilization (IVF), the incidence of twin pregnancies remains high ( Martin et al., 2013 PRN, 2014). The global incidence of multiple pregnancies has increased both due to the introduction of artificial reproductive technologies and due to increasing maternal age. Twin pregnancy, fetal reduction, congenital abnormality, pregnancy outcome Introduction

Lost twins at 13 weeks