title: First-trimester fetal growth discordance and development of preeclampsia in dichorionic twin pregnancies.
abstract: OBJECTIVE
  To investigate the relation between first-trimester fetal growth discrepancy, as assessed by crown-rump length (CRL) at 11+0 to 13+6 weeks of gestation, and subsequent development of preeclampsia (PE) in dichorionic diamniotic (DCDA) twin pregnancies. The association between inter-twin CRL and birth weight (BW) discrepancy was also investigated.
  
  
  METHODS
  This was a retrospective, case-control study of DCDA twin pregnancies. Inter-twin CRL discrepancy was calculated as 100×(larger CRL-smaller CRL)/larger CRL. BW discordance was calculated as 100×(larger BW-smaller BW)/larger BW.
  
  
  RESULTS
  The study included 299 DCDA pregnancies that remained normotensive and 35 that subsequently developed PE. There was no significant difference in the inter-twin CRL discrepancy between pregnancies complicated by PE and those that were not [3.2%, interquartile range (IQR): 0.5-4.5% vs. 3.3%, IQR: 1.4-5.5%; P=0.17]. There was a positive correlation between inter-twin CRL and BW discrepancy but only in pregnancies that remained normotensive (P<0.001). In women that subsequently developed PE, there was no association between inter-twin CRL and BW discordance (P=0.54).
  
  
  CONCLUSIONS
  In unselected DCDA twins, first-trimester CRL discrepancy is not different between pregnancies that subsequently develop PE and those that remain normotensive. Furthermore, in pregnancies that are complicated by PE, the association between inter-twin CRL and BW discrepancy appears to be lost.
authors.forename: Tanya
authors.initials: T
authors.lastname: Maric
authors.forename: Natasha
authors.initials: N
authors.lastname: Singh
authors.forename: Keith
authors.initials: K
authors.lastname: Duncan
authors.forename: Guy J
authors.initials: GJ
authors.lastname: Thorpe-Beeston
authors.forename: Makrina D
authors.initials: MD
authors.lastname: Savvidou
mesh_terms: D000328:Adult; D001724:Birth Weight; D016022:Case-Control Studies; D018568:Crown-Rump Length; D005260:Female; D047109:Fetal Development; D006801:Humans; D016015:Logistic Models; D011225:Pre-Eclampsia / Q000175:diagnosis / Q000209:etiology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D059285:Pregnancy, Twin; D012189:Retrospective Studies; D014429:Twins, Dizygotic; D016216:Ultrasonography, Prenatal