title: The influence of assisted reproductive technology on growth discordance in dichorionic twin pregnancies.
abstract: OBJECTIVE
  We examined the relation between first-trimester crown-rump length (CRL) discordance and birth weight discordance in dichorionic twin pregnancies conceived by assisted reproductive technology (ART).
  
  
  METHODS
  We examined 101 nulliparous dichorionic twin pregnancies producing male-male or female-female infants conceived spontaneously (n = 38) or following in vitro fertilization and embryo transfer (n = 63).
  
  
  RESULTS
  There were no significant differences in CRL disparity or birth weight discordance between spontaneous and ART-conceived dichorionic twin pregnancies. There was a positive correlation between CRL disparity and birth weight discordance in ART-conceived twin pregnancies (r(2) = 0.22, p = 0.02), while there was no such correlation in spontaneous pregnancies (r(2) = 0.02, p = 0.40).
  
  
  CONCLUSIONS
  In ART-conceived dichorionic twin pregnancies, CRL disparity may be associated with birth weight discordance.
authors.affiliation: Department of Obstetrics and Gynecology, Japanese Red Cross Katsushika Maternity Hospital, Katsushika-ku, Tokyo, Japan. czg83542@mopera.ne.jp <czg83542@mopera.ne.jp>
authors.forename: Shunji
authors.initials: S
authors.lastname: Suzuki
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Murata
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000502:physiology; D018568:Crown-Rump Length; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D006801:Humans; D008297:Male; D011247:Pregnancy; D027724:Reproductive Techniques, Assisted / Q000009:adverse effects; D014427:Twins / Q000502:physiology*