title: Acute feTal behavioral Response to prenatal Yoga: a single, blinded, randomized controlled trial (TRY yoga).
abstract: BACKGROUND
  In 2012, yoga was practiced by 20 million Americans, of whom 82% were women. A recent literature review on prenatal yoga noted a reduction in some pregnancy complications (ie, preterm birth, lumbar pain, and growth restriction) in those who practiced yoga; to date, there is no evidence on fetal response after yoga.
  
  
  OBJECTIVE
  We aimed to characterize the acute changes in maternal and fetal response to prenatal yoga exercises using common standardized tests to assess the well-being of the maternal-fetal unit.
  
  
  METHODS
  We conducted a single, blinded, randomized controlled trial. Uncomplicated pregnancies between 28 0/7 and 36 6/7 weeks with a nonanomalous singleton fetus of women who did not smoke, use narcotics, or have prior experience with yoga were included. A computer-generated simple randomization sequence with a 1:1 allocation ratio was used to randomize participants into the yoga or control group. Women in the yoga group participated in a 1-time, 1 hour yoga class with a certified instructor who taught a predetermined yoga sequence. In the control group, each participant attended a 1-time, 1 hour PowerPoint presentation by an obstetrician on American Congress of Obstetricians and Gynecologists recommendations for exercise, nutrition, and obesity in pregnancy. All participants underwent pre- and postintervention testing, which consisted of umbilical and uterine artery Doppler ultrasound, nonstress testing, a biophysical profile, maternal blood pressure, and maternal heart rate. A board-certified maternal-fetal medicine specialist, at a different tertiary center, interpreted all nonstress tests and biophysical profile data and was blinded to group assignment and pre- or postintervention testing. The primary outcome was a change in umbilical artery Doppler systolic to diastolic ratio. Sample size calculations indicated 19 women per group would be sufficient to detect this difference in Doppler indices (alpha, 0.05; power, 80%). Data were analyzed using a repeated-measures analysis of variance, a χ(2), and a Fisher exact test. A value of P < .05 was considered significant.
  
  
  RESULTS
  Of the 52 women randomized, 46 (88%) completed the study. There was no clinically significant change in umbilical artery systolic to diastolic ratio (P = .34), pulsatility index (P = .53), or resistance index (P = .66) between the 2 groups before and after the intervention. Fetal and maternal heart rate, maternal blood pressure, and uterine artery Dopplers remained unchanged over time. When umbilical artery indices were individually compared with gestational age references, there was no difference between those who improved or worsened between the groups.
  
  
  CONCLUSIONS
  There was no significant change in fetal blood flow acutely after performing yoga for the first time in pregnancy. Yoga can be recommended for low-risk women to begin during pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Truman Medical Center, Kansas City, MO. Electronic address: babbarsh@umkc.edu.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Babbar
authors.affiliation: Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA.
authors.forename: James B
authors.initials: JB
authors.lastname: Hill
authors.affiliation: Department of Bioinformatics, University of Missouri Kansas City, Kansas City, MO.
authors.forename: Karen B
authors.initials: KB
authors.lastname: Williams
authors.affiliation: Department of Obstetrics and Gynecology, Truman Medical Center, Kansas City, MO.
authors.forename: Maria
authors.initials: M
authors.lastname: Pinon
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Health Science Center-Houston, Houston, TX.
authors.forename: Suneet P
authors.initials: SP
authors.lastname: Chauhan
authors.affiliation: Department of Obstetrics and Gynecology, Truman Medical Center, Kansas City, MO.
authors.forename: Dev
authors.initials: D
authors.lastname: Maulik
mesh_terms: D000328:Adult; D001794:Blood Pressure; D005260:Female; D005333:Fetus / Q000502:physiology*; D006340:Heart Rate, Fetal; D006801:Humans; D009068:Movement; D011247:Pregnancy; D011295:Prenatal Care; D011673:Pulsatile Flow; D016037:Single-Blind Method; D018608:Ultrasonography, Doppler; D014469:Umbilical Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D055988:Uterine Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D014655:Vascular Resistance; D015013:Yoga; D055815:Young Adult
keywords: fetal behavior; fetal response; prenatal yoga; yoga pregnancy