title: Impact of single embryo transfer policy on perinatal outcomes in fresh and frozen cycles-analysis of the Japanese Assisted Reproduction Technology registry between 2007 and 2012.
abstract: OBJECTIVE
  To investigate whether the introduction of single embryo transfer (SET) policy in Japan has improved perinatal outcomes.
  
  
  METHODS
  A retrospective cohort study.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  A total of 140,718 live births and 510 stillbirths (after 22 weeks of gestation) conceived by assisted reproductive technology in Japan between 2007 and 2012 were reviewed.
  
  
  METHODS
  None.
  
  
  METHODS
  Preterm birth (PTB), low birth weight (LBW), very low birth weight (VLBW), small for gestational age (SGA), large for gestational age (LGA), perinatal mortality, and other pregnancy complications.
  
  
  RESULTS
  The rate of SET increased significantly from 52.2% in 2007 to 82.6% in 2012, while the rate of multiple pregnancy decreased significantly from 10.7% to 4.1% over the same period. The rates of PTB, LBW, and SGA decreased significantly, while that of LGA increased. Perinatal mortality decreased from 0.70% to 0.40% in fresh cycles, while that of frozen cycles did not change. Double ET or more was associated with a significantly increased risk for multiple pregnancy, placenta accreta, preterm premature rupture of membrane, cesarean section (CS), PTB, LBW, SGA, and early neonatal death compared with SET. Compared with before the SET policy was launched, the risks of multiple pregnancy, CS, early PTB before 32 weeks, LBW, VLBW, and SGA were significantly decreased after the policy was launched, with significant interactions of fresh/frozen status.
  
  
  CONCLUSIONS
  The results suggest that the SET policy improved perinatal outcomes in Japan. The impact of SET policy was different in fresh and frozen cycles for several perinatal outcomes.
authors.affiliation: Division of Reproductive Medicine, Center of Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan. Electronic address: kazumitakeshima@gmail.com.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Takeshima
authors.affiliation: Division of Reproductive Medicine, Center of Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan; SORA no MORI clinic, Okinawa, Japan.
authors.forename: Seung Chik
authors.initials: SC
authors.lastname: Jwa
authors.affiliation: Division of Reproductive Medicine, Center of Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Saito
authors.affiliation: SORA no MORI clinic, Okinawa, Japan.
authors.forename: Aritoshi
authors.initials: A
authors.lastname: Nakaza
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, University of Tokushima, Tokushima, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kuwahara
authors.affiliation: Department of Obstetrics and Gynecology, Saitama Medical University, Saitama, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Ishihara
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, University of Tokushima, Tokushima, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Irahara
authors.affiliation: Department of Obstetrics and Gynecology, Yokohama City University Graduate School of Medicine, Hukuura, Kanazawa-ku, Yokohama City, Kanagawa, Japan.
authors.forename: Fumiki
authors.initials: F
authors.lastname: Hirahara
authors.affiliation: Yoshimura Bioteic Literacy Institute, Tokyo, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Yoshimura
authors.affiliation: SORA no MORI clinic, Okinawa, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sakumoto
mesh_terms: D000328:Adult; D015925:Cryopreservation; D046149:Embryo Culture Techniques; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro / Q000009:adverse effects / Q000401:mortality; D006801:Humans; D007231:Infant, Newborn; D007246:Infertility / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D007564:Japan; D050498:Live Birth; D008297:Male; D054238:Perinatal Mortality; D011050:Policy Making; D011247:Pregnancy; D011248:Pregnancy Complications / Q000401:mortality / Q000517:prevention & control*; D018873:Pregnancy Rate; D015397:Program Evaluation; D012042:Registries; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D056826:Single Embryo Transfer / Q000009:adverse effects / Q000401:mortality; D013997:Time Factors; D016896:Treatment Outcome
keywords: Assisted reproductive technology; low birth weight; perinatal outcome; preterm delivery; single embryo transfer