title: Blastocyst culture is associated with an elevated incidence of monozygotic twinning after single embryo transfer.
abstract: In a 7-year (2002-2008) retrospective study of a large IVF program based on minimal ovarian stimulation and single ET (47,841 single ETs), monozygotic twinning occurred in 1.01% of 14,956 clinical pregnancies. Blastocyst culture was associated with a significantly increased monozygotic twinning risk (adjusted odds ratio, 2.04; 95% confidence interval, 1.29-4.48), whereas embryo freezing, type of stimulation protocol used, intracytoplasmic sperm injection fertilization, or zona removal did not influence its incidence.
authors.affiliation: Kato Ladies Clinic, Tokyo, Japan. s-kawachiya@towako-kato.com
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kawachiya
authors.forename: Daniel
authors.initials: D
authors.lastname: Bodri
authors.forename: Naoko
authors.initials: N
authors.lastname: Shimada
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kato
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takehara
authors.forename: Osamu
authors.initials: O
authors.lastname: Kato
mesh_terms: D000328:Adult; D001724:Birth Weight; D001755:Blastocyst / Q000166:cytology*; D002478:Cells, Cultured; D015331:Cohort Studies; D046149:Embryo Culture Techniques; D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008423:Maternal Age; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data*; D047928:Premature Birth / Q000453:epidemiology; D012189:Retrospective Studies; D056826:Single Embryo Transfer / Q000706:statistics & numerical data*; D038522:Twinning, Monozygotic / Q000502:physiology; D014430:Twins, Monozygotic