title: Strenuous exercise during pregnancy: is there a limit?
abstract: OBJECTIVE
  The purpose of this study was to evaluate fetal responses to strenuous exercise in physically active and inactive women.
  
  
  METHODS
  Forty-five healthy women (15 who were nonexercisers, 15 who were regularly active, 15 who were highly active) underwent a peak treadmill test at 28 weeks' gestation to 32 weeks 6 days' gestation. Fetal well-being (umbilical artery Doppler indices, fetal heart tracing/rate, biophysical profile [BPP]) was evaluated before and after exercise. Uterine artery Doppler scans were also obtained.
  
  
  RESULTS
  Umbilical and uterine artery Doppler indices were similar among activity groups and did not change with exercise (P > .05). BPP and fetal heart tracings were reassuring in all groups. However, subgroup analyses showed transient fetal heart rate decelerations after exercise and elevated umbilical and uterine artery Doppler indices in 5 highly active women. After this, BPP and fetal heart tracings were reassuring.
  
  
  CONCLUSIONS
  Overall fetal well-being is reassuring after short-duration, strenuous exercise in both active and inactive pregnant women. A subset of highly active women experienced transient fetal heart rate decelerations and Doppler changes immediately after exercise. Athletes may push beyond a threshold intensity at which fetal well-being may be compromised. However, potential impact on neonatal outcomes is unknown.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Linda M
authors.initials: LM
authors.lastname: Szymanski
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Satin
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005333:Fetus / Q000502:physiology*; D006340:Heart Rate, Fetal; D006801:Humans; D011247:Pregnancy; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging / Q000502:physiology; D055988:Uterine Artery / Q000648:ultrastructure