We know now, that sport and physical activity are important, even essential at any stage of a human being’s life. Pregnancy does not break this rule. But why is it so important ? Wouldn’t it be, in the contrary, dangerouse both for mother and child ?
A lot of studies were conducted throughout many decades since the middle of the 20th century to finally conclude that pregnancy is recognized as a unique time for behavior modifications and is no longer considered a condition for confinement.
The most obvious pain induced by the gradual growth of the fetus during gestation is the development of lumbar lordosis, which contributes to the very high prevalence of low back pain in pregnant women. A training routine including exercises of core stabilization strengthens the back muscles and helps with weight bearing. Furthermore, a better core stabilization means stronger pelvic floor muscles, a very important muscle group during pregnancy.
Also, anatomical and physiological changes during pregnancy have the potential to affect the musculoskeletal system. The weight gain may significantly increase the forces across joints (hips and knees) and causes discomfort or worse, increases damages due to arthritis or previously unstable joints.
Pregnancy induces profound alterations in maternal haemodynamics (response of the body to physical activities, which adjust its blood flow in order to deliver properly the nutrients to stressed tissues and allow them to function), which appear to establish a circulatory reserve necessary to provide nutrients and oxygen to both mother and fetus at rest and during moderate physical activity. Such changes include an increase in blood volume, heart rate, and stroke volume as well as cardiac output, and a decrease in systemic vascular resistance. Furthermore, it is know that sedentary habits and low levels of cardio respiratory fitness are leading risk factors for subsequent development of cardiovascular disease (heart attack and failure, ischemic stroke, arrhythmia…).
About the mother
These are some of the numerous arguments that encourage The Centers for Disease Control and Prevention and the American College of Sports Medicine (CDC-ACSM) to recommend the accumulation of 30 minutes or more of moderate intensity (60–70% of maximal heart rate or 50–60% of maximal oxygen uptake) physical activity on most, and preferably every day of the week (we are speaking about pregnant women, but it is possible to apply the same recommendations to anyone not used to sport).
It was found that relatively low weights lifted through a dynamic range of motion for multiple repetitions appear to be a safe and effective type of resistance exercise during pregnancy.
However, there are precautions to keep in mind when beginning a sport or physical routine during pregnancy, and it must include the advice of a personal trainer and/or a physician, and a clinical evaluation of each pregnant woman should be conducted before an exercise program is recommended.
After the first trimester, the supine and prone position as well as motionless standing should be avoided because it results in relative obstruction of venous return and therefore decreased cardiac output.
There are several activities that create increased risks in pregnancy. During scuba diving, for example, the fetus is at increased risk of decompression sickness secondary to the inhability of the fetal pulmonary circulation to filter bubble formation. Swimming, however, has not been associated with adverse effects and is well tolerated. Thereupon, in studies of immersion exercise in pregnancy at 60% maximal oxygen consumption, swimming was found to be a safe activity, with advantageous effects on edema, thermal regulation, and buoyancy, thus minimizing the risk of joint injuries.
Others examples of sports to avoid are activities that increase the risk of falls, such as skiing, or those that may result in excessive joint stress, such as jogging and tennis. In addition, physical activity with a high risk of abdominal trauma should be considered undesirable. Furthermore, it would be prudent to limit repetitive isometric or heavy resistance weightlifting and any exercises that result in a large pressor effect (increased blood pressure) during pregnancy.
Because of the increased relaxation of ligaments during pregnancy, flexibility exercises should be individualized. Maintenance of normal joint range of motion, however, should not interfere with a moderate exercise routine in pregnant women.
The recommendations above should not preclude pregnant women from engaging in physical activity. Indeed, there are a lot of activities one could think were created for pregnancy, because they are so suitable for this particular condition.
The better example I can give you is yoga. Prenatal and postnatal yoga are practices purposely created for the gestational and lactation period.
Yoga is a constellation of slow dynamic and static movements, during which you focus on the breath while controlling the stretching and strengthening of skeletal muscles. Traditional goals of childbirth education have been to reduce pain and anxiety through relaxation techniques that have their roots in yoga. Observational studies and randomized trials have demonstrated an improvement in the quality of life by decreasing stress, anxiety, and sleep disturbances through yoga practice during pregnancy. The biological plausibility of the finding comes from the fact that during pregnancy, stressors activate the hypothalamic-pituitary-adrenal axis (HPA axis controls reaction to stress and regulates many body processes), and yogic relaxation techniques reduce sympathetic tone, decreasing the effects of these stressors.
Beside yoga there are many other physical activities that pregnant women could engage in, but what we want to know is how beneficial and healthy sport and leisure activities are.
The first argument is the decrease of symptoms of pregnancy such as somatic complaints, insomnia, anxiety, nausea, leg cramps, round ligament pain…. Several studies found that more active women reported experiencing fewer symptoms than less active women. Furthermore, the data showed clearly that women who exercised more in the 3 months before pregnancy felt better in the first trimester, and those who exercised more in the first and second trimesters felt better in the third trimester.
Physiologically, exercising during pregnancy could decrease the severity of pregnancy symptoms by increasing Beta-endorphin levels above the increase associated with pregnancy itself. The higher Beta-endorphin levels are during labor, the lower the perception of pain is going to be.
That leads us to the second argument: the benefit of pregnancy exercise during labor. It was shown that well-conditioned and highly trained women experience more vaginal deliveries, fewer obstetric interventions, with comfortable and shorter labor.
From a standpoint of internal health, women who reported vigorous activity before pregnancy and light-to-moderate or vigorous activity during pregnancy appeared to have a lower risk of both gestational diabetes mellitus and abnormal glucose tolerance compared with women reporting these activities in neither time period. So it shows us that even without a baby in the belly, we should always move ourselves, our body will always thank us.
About the baby
What does the fetus think about mumy’s training while he is growing inside her ? Well, for a long time it was thought that it could affect the child and that is probably why we care too much about the pregnancy condition and unconsciously try to put pregnant women in hermetic bubbles.
But a lot of studies showed otherwise. One of them, based on a physical program which included a total of three (Monday, Wednesday, Friday) 35 minute weekly sessions from the start of the second trimester (weeks 12–13) to the end of the third trimester (weeks 38–39). Thus, an average of 80 training sessions was originally planned for each participant in the event of no preterm delivery. The main finding of this study was that supervised, moderate exercise training performed over the second and third trimester of pregnancy does not negatively affect any of the main pregnancy outcomes and gestational age at the moment of delivery. Also the overall health status of the baby is unaffected.
The consequences of sport on the selective redistribution of blood flow during regular or prolonged exercise in pregnancy, according to some studies, does not interfere with the transplacental transport of oxygen, carbon dioxide, and nutrients. Given this concern, water exercise may be an excellent choice of exercise during pregnancy because, during immersion, a centripetal (which approaching the center) shift in blood volume occurs.
Exercise routines may be resumed only gradually after pregnancy and should be individualized. Physical activity can thus be resumed as soon as physically and medically safe. Nursing before exercise is recommended in order to avoid the potential problems associated with increased acidity of milk secondary to any build up of lactic acid. Finally, a return to physical activity after pregnancy has been associated with decreased postpartum depression, but only if the exercise is stress relieving and not stress provoking.
So, all the tools are here; between nutrition (macro & micro), harmful behavior to avoid, and physical activity to give the best chances for mother and child to enjoy a safe and healthy gestation and lactation period. With this knowledge, a little bit of curiosity and the advise of both physician and physical activity professional, future mothers should give birth to the “perfectly healthy” baby.
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