title: The individual fetal weight/estimated placental weight ratios in monochorionic twins with selective intrauterine growth restriction.
abstract: OBJECTIVE
  To evaluate the individual fetal weight/estimated placental weight ratios (F/P ratio) of the two fetuses in monochorionic (MC) twins with selective intrauterine growth restriction (IUGR).
  
  
  METHODS
  MC twin with selective IUGR was defined as an estimated fetal weight below the 10th percentile in one twin of MC pregnancy. The estimated individual placental weight was obtained by cutting the placenta along the vascular equator into two territories. A total of 15 MC twins with selective IUGR and 18 MC twins without selective IUGR were included in this study.
  
  
  RESULTS
  The individual F/P ratio in the IUGR twin is significantly higher than that in the appropriate for gestational age (AGA) one in MC twin with selective IUGR (6.4 vs 4.0 respectively, p < 0.001). In MC twin without IUGR, the F/P ratios are not significantly different between the two fetuses (5.4 vs 5.1, respectively).
  
  
  CONCLUSIONS
  The high F/P ratio in the IUGR twin in MC with selective IUGR may be due to the placental reserve phenomenon, so that a smaller placental territory may suffice to perfuse the IUGR twin. In other words, in MC twin gestations with an IUGR twin, the fetal weights are not proportional to the placental masses.
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 5, Fu-Shin Street, Kweishan, Taoyuan 333, Taiwan, ROC. j12054@cgmh.org.tw
authors.forename: Yao-Lung
authors.initials: YL
authors.lastname: Chang
authors.forename: Shuenn-Dyh
authors.initials: SD
authors.lastname: Chang
authors.forename: An-Shine
authors.initials: AS
authors.lastname: Chao
authors.forename: Peter C C
authors.initials: PC
authors.lastname: Hsieh
authors.forename: Chao-Nin
authors.initials: CN
authors.lastname: Wang
authors.forename: Ling-Hong
authors.initials: LH
authors.lastname: Tseng
mesh_terms: D002823:Chorion; D005260:Female; D005317:Fetal Growth Retardation / Q000175:diagnosis*; D020567:Fetal Weight; D005865:Gestational Age; D006801:Humans; D010920:Placenta / Q000503:physiopathology*; D011247:Pregnancy; D011446:Prospective Studies; D014430:Twins, Monozygotic