Acute Maternal and Fetal Effects of Exercise in Pregnancy
Condition: Blood Pressure; Heart Rate and Rhythm Disorders; Hypoglycemia; Lactate; Nitrate; Cholesterol (Total and HDL); Abnormality in Fetal Heart Rate or Rhythm, Unspecified as to Episode of Care
MeSH terms: Hypoglycemia
Study type: Interventional

Summary: 
      This will be an open randomized clinical trial involving pregnant women between 35 and 37
      weeks randomized to two modalities of exercise: treadmill or stationary bike. The study
      hypothesis is that exercise on a stationary cycle causes less maternal and fetal effects in
      relation to treadmill exercise.We will study the acute effects of exercise for both the
      mother and the fetus, monitoring the parameters before, during and after exercise for 20
      minutes. The exercise intensity will be moderate, remaining between 60% and 80% of maximum
      heart rate. Women will be monitored with a recording equipment of ABPM (ambulatory blood
      pressure monitorization) and continuous cardiotocography and blood will be collected to
      measure blood glucose, total cholesterol and HDL, nitrate and lactate before, during and
      after exercise. The analysis variables are: maternal heart rate and blood pressure, fetal
      heart rate, number of fetal movements, transient accelerations, decelerations, short-term
      variability, episodes of high variability, uterine tone, glucose, lactate, nitrate, total
      cholesterol and HDL.The analysis will be based on intention to treat, according to the
      recommendations of the CONSORT (2010).
    

Detailed description: 
      Background: Exercise has been encouraged during pregnancy in order to reduce undesirable
      outcomes such as pre-eclampsia, excessive weight gain and diabetes. Despite widespread among
      pregnant women and obstetricians, little is known about the acute effects for both mother and
      fetus at the time of exercise, with most existing research controlling only the pre-and
      post-exercise.

      Objective: To study the acute effects of two moderate modalities of exercise on the pregnant
      woman and fetus.

      Methods: This will be an open randomized controlled trial to be conducted in Campina Grande,
      Brazil, from December 2011 to December 2012. The pregnant women with gestational age between
      35 and 37 weeks will be randomized into two groups of moderate-intensity exercise: treadmill
      and stationary bicycle. Pregnant women and fetuses will be monitored for 60 minutes divided
      in three steps of 20 minutes each: baseline assessment, monitoring during exercise and
      recovery period. Women will be monitored using a recording equipment of ABPM (ambulatory
      blood pressure monitorization) and fetal heart rate will be monitored through computerized
      cardiotocography. Blood will be collected to measure blood glucose, total cholesterol and
      HDL, nitrate and lactate before, during and after exercise. The intensity of exercise will be
      maintained between 60% and 80% of maximum heart rate by Karvonen formula, in addition to the
      subjective perception of exertion on the modified Borg scale (moderate intensity). During the
      monitoring period (in the three moments mentioned above) blood will be collected for the
      measurement of glucose, total cholesterol and HDL, nitrate and lactate. The analysis
      variables are: maternal heart rate and blood pressure, fetal heart rate, number of fetal
      movements, transient accelerations, decelerations, short-term variability, episodes of high
      variability, uterine tone, glucose, lactate, nitrate, total cholesterol and HDL

      Statistical Analysis: Statistical analysis will be performed using Epi Info 3.5.3 and Medcalc
      11.6.6.0 or higher versions available at the time. The analysis will be based on intention to
      treat, according to the recommendations of the CONSORT (2010). For comparison of levels of
      glucose, lactate, cholesterol, nitrate, maternal blood pressure, maternal and fetal heart
      rate, fetal movements, transient accelerations, decelerations, changes in short-term episodes
      of high variation, and uterine tone in the two groups a parametric test will be used
      (Student's t) if these variables have normal distribution, otherwise they will be evaluated
      using the nonparametric test of Mann-Whitney. To determine the association between mode of
      exercise and frequency of fetal bradycardia the chi-square test of association (Pearson) will
      be used at a 5% significance level. The risk ratio (RR) will be calculated as a measure of
      relative risk, as well as its 95% confidence interval. If a significant difference in the
      rate of bradycardia will be demonstrated between the groups, the NNH (Number Need Harm) will
      be calculated.

      Ethical issues: The research project was approved by Institutional Review Board under the
      number CAAE 0195.0.133.000-11 All the participants will be informed about the objectives of
      the research and only will be included if they agree voluntarily to participate and sign an
      informed consent term. There are no conflicts of interest.
    

Intervention name(s): Physical exercise
Intervention type(s): Other
Intervention description(s): Two modalities of exercise will be compared: treading mill and stationary bicycle. Pregnant women enrolled in the study will perform exercise during 20 minutes and will be monitored 20 minutes before, during and 20 minutes after exercise.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Keywords: Physical exercise; Pregnancy; Fetal well being