title: Adaptive responses of cardiac function to fetal postural change as gestational age increases.
abstract: OBJECTIVE
  The cardiovascular system maintains homeostasis through a series of adaptive responses to physiological requirements. However, little is known about the adaptation of fetal cardiac function to gravity, according to gestational age. In the present study, we aimed to evaluate the adaptive responses of cardiac function to postural changes, using Tei index measurements.
  
  
  METHODS
  Fetal echocardiography and Doppler examination were performed on 114 women with vertex singleton pregnancies at 19 to 40 weeks' gestation. Participants were placed in an upright seated position, and the Tei index for fetal left ventricular cardiac function was measured. The women were then moved into a supine position and the Tei index was re-measured.
  
  
  RESULTS
  The mean Tei index when measured in an upright seated position was significantly lower than that measured in a supine positioning for all fetuses (0.528±0.103 vs. 0.555±0.106,P=0.014, respectively). This difference was also noted in fetuses with a gestational age of 28-40 weeks (0.539±0.107 vs. 0.574±0.102,P=0.011, respectively). However, there was no difference in the Tei index between an upright seated and a supine position among fetuses with a gestational age of <28 weeks (0.505±0.091 vs. 0.516±0.103,P=0.571, respectively).
  
  
  CONCLUSIONS
  Postural changes from an upright seated to a supine position result in an increased Tei index after a gestational age of 28 weeks. This appears to reflect maturation in the adaptive responses of the fetal cardiovascular system to postural changes.
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Kim
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Choi
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Yang
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Boo Hae
authors.initials: BH
authors.lastname: Koo
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Ki Hoon
authors.initials: KH
authors.lastname: Ahn
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Geum Joon
authors.identifier: 0000-0001-6761-0944
authors.initials: GJ
authors.lastname: Cho
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Soon Cheol
authors.initials: SC
authors.lastname: Hong
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Min-Jeong
authors.initials: MJ
authors.lastname: Oh
authors.affiliation: Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
authors.forename: Hai-Joong
authors.initials: HJ
authors.lastname: Kim
keywords: Fetus; Gestational age; Postural change; Tei index