title: Uterine contractions might increase heart preload in the recipient fetus in early-onset twin-twin transfusion syndrome: an ultrasound assessment.
abstract: OBJECTIVE
  Uterine contractions (UC) in twin pregnancy are often experienced, yet the effects of UC in twin-twin transfusion syndrome (TTTS) remain to be clarified. The recipient heart preload condition and the effects of UC were evaluated and the final objective was to clarify the effects of tocolysis.
  
  
  METHODS
  Firstly, the preload indexes (PLIs) and cardiothoracic area ratios (CTARs) were analyzed on both fetuses of 10 TTTS cases, aged from 14 to 28 gestational weeks in stage III/IV cases for evaluating the preload condition. Then, the PLIs in the presence and absence of UC in the recipient fetuses were determined to evaluate the difference.
  
  
  RESULTS
  The PLIs of the recipient and the donor fetuses were 0.78 +/- 0.34 (n = 163) and 0.35 +/- 0.13 (n = 71) respectively. The CTARs were 30.2 +/- 6.1 (n = 62) and 23.4 +/- 5.4 (n = 62) respectively. The PLIs in the absence and presence of UC in the recipient fetuses were 0.69 +/- 0.29 and 0.99 +/- 0.38 (n = 35). All above comparisons showed highly significant differences (p < 0.0001).
  
  
  CONCLUSIONS
  The recipient fetuses have signs of cardiac dilatation and a high-preload condition. UC transiently further raises high-preload conditions of the recipient fetus. Thus, tocolysis may be necessary for management in cases of early-onset severe TTTS.
authors.affiliation: Department of Obstetrics and Gynecology, Gifu University School of Medicine, Tsukasamachi-40, Gifu City 500-8705, Japan. y-taka@cc.gifu-u.ac.jp
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Shigenori
authors.initials: S
authors.lastname: Iwagaki
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawabata
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Tamaya
mesh_terms: D004108:Dilatation, Pathologic / Q000000981:diagnostic imaging / Q000196:embryology; D005260:Female; D005318:Fetal Heart / Q000473:pathology / Q000503:physiopathology*; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy; D006321:Heart / Q000196:embryology; D006801:Humans; D011247:Pregnancy; D013909:Thorax / Q000000981:diagnostic imaging / Q000196:embryology; D015145:Tocolysis; D016216:Ultrasonography, Prenatal; D014590:Uterine Contraction / Q000502:physiology*