Excerpt from: Go Ahead, Stop & Pee: Running During Pregnancy and Postpartum
By Kate Mihevc-Edwards PT, DDC, OCS and Blair Green, PT, DDC, OCS
Running during pregnancy is more common than ever. There is a whole new industry of running shirts with statements such as: "Running for two," "Yes, my doctor says itís okay to run," and "No, I did not swallow a pumpkin!" Research has proven that for most women, running during pregnancy is a good thing. What you need to understand as a pregnant runner or health care provider is that the body undergoes tremendous physical change during pregnancy. Underestimating what is happening in the body can cause frustration when running times get progressively slower, or when typical runs of three to five miles seem much more difficult. Understanding the changes that the body is undergoing will allow pregnant women to run more confidently. It will also help health care providers treat their clients more effectively. While some changes occur rapidly and early on in pregnancy, others develop gradually. Each trimester (13 weeks) of pregnancy is characterized by its own set of physiological changes. Some of these changes are visible, such as weight gain and postural adaptations. Others, including cardiovascular and hormonal changes, are not as obvious, but are equally significant. There is overwhelming support for exercise during pregnancy; however, understanding your bodyís changes will help you understand what is a normal response to exercise, and what may require more attention.
The Institute of Medicine updated its recommendation for weight gain in pregnancy in 2009. It recommends a weight gain of 25-35 pounds for singleton pregnancies. This may vary from person to person. Factors include pre-pregnancy weight, activity level, and fluid retention. It is recommended that women who are underweight gain up to 40 pounds during pregnancy, while those who are overweight not gain more than 15 pounds. Pregnancy weight may include the weight of the fetus, placenta, breast tissue, fat stores, and fluid. Research shows that continuing to exercise throughout pregnancy does not seem to affect gestational weight gain, dispelling a myth that exercise may harm the growth of the baby. Also, remember that it is not appropriate to use exercise during pregnancy as a means to minimize or prevent weight gain.
BONES, JOINTS, AND LIGAMENTS
The skeletal and ligamentous structures in the body support the growing fetus. They also help prepare the body for childbirth by becoming more "lax." As the baby grows, the motherís posture begins to change. The rib cage may become flared, and the natural arch in the spine, known as lordosis, may increase. Increasing lordosis may cause the pelvis to tilt anteriorly and tighten the hip flexor muscles. The thoracic spine may also become more rounded as breast size increases. Some women develop more of a swayback posture, with the hips and pelvis anterior to the shoulders, and a posterior pelvic tilt. Hormones, such as relaxin and progesterone, affect all of the bodyís connective tissue. In the bony skeleton, the pelvis widens, primarily at the joint in the front, the pubic symphysis. Joints may feel "looser" or easier to stretch than they felt prior to pregnancy. The arches of the feet may flatten. Another change in the joints is a reduction in synovial fluid. Synovial fluid is the lubrication for the joints (like oil in an engine). It is important to recognize this change because it may take longer to warm up joints while exercising.
The muscular system adapts to the changing bony framework of the skeleton. With changes in posture, the muscles may lengthen or shorten. Moreover, laxity in the ligaments may place more demand on the muscular system to provide support with movement. Muscles that typically become tight include lumbar paraspinals, psoas, iliacus, hip flexors, adductors (inner thigh), and pectoralis muscles (chest). Muscles that typically become lengthened include abdominals, hamstrings, glutes, and posterior shoulder muscles. A common occurrence in pregnancy is a stretching of the fascia (connective tissue) in the abdominal wall at the linea alba (midline). This is known as diastasis recti abdominis (DRA), and affects up to two-thirds of all pregnancies. Tissue laxity, coupled with a stretching abdomen, causes this to occur. It is not an emergency, and with appropriate attention and modifications, there is no reason a woman cannot exercise with DRA. Exercise modifications for DRA will be discussed later.
Cardiovascular changes begin in the first trimester. Like the ligaments, the blood vessels also become lax. Blood pressure initially decreases. This is known as "underfill." The biggest symptom of underfill is dizziness with position changes. During the second trimester, blood volume begins to increase and can increase up to 50 percent by the end of the second trimester. Blood pressure returns to normal postpartum. Varicose veins are a common occurrence in pregnancy. It is common to see varicose veins in the legs, as well as in the vulva. The risk of varicose veins increases in pregnancy because of laxity in the blood vessels. Compression garments may help minimize the varicosities and improve circulation. In the first trimester, there is also an increased demand for oxygen. Heart rate increases in response to this demand. If you monitor your heart rate while running, you may find that it is higher than normal, or increasing rapidly as you begin to exercise. It may be necessary to slow your pace, for the warm-up or for the entire run, especially as pregnancy advances. In the third trimester, blood pressure may begin to rise. It is important to monitor it as pregnancy advances, as hypertension (blood pressure greater than 140/90) is a sign of a medical emergency known as pre-eclampsia. Other signs of pre-eclampsia, or pregnancy-induced hypertension, include swelling in the legs and ankles, headaches, right-sided upper abdominal pain, blurred vision, and rapid weight gain (over one to two days). One phenomenon to consider with exercise is supine hypotension. This occurs around week 20 of pregnancy and can continue through delivery. It happens when the pregnant woman lies on her back. The weight of the fetus can compress the inferior vena cava, which is the main vein that returns blood to the heart. The result is a drop in blood pressure, which can leave the woman feeling dizzy or lightheaded, and in some extreme cases, can even cause the woman to pass out. The important thing to know about supine hypotension is that when it occurs, it does not harm the baby at all. Still, there is some evidence that at full term, lying supine may impede blood flow to the fetus31. It is also completely preventable by limiting the amount of time that the pregnant woman spends on her back while exercising. Many exercises and stretches can be modified to standing, side lying, or sitting to prevent supine hypotension.
The demand for oxygen increases in pregnancy, with half of all oxygen inhaled going to the uterus. In addition, the shape of the diaphragm may change, due to its attachment to the rib cage, as well as the growing fetus leaving less room for this muscle to descend on inhalation. Respiratory rate may increase to accommodate these changes; however, the pulmonary system does a good job of adapting to maximize oxygen absorption with each breath31. Increasing warm-up time and lowering running pace can help minimize the risk of shortness of breath as pregnancy progresses.
A common side effect of pregnancy is increased urine output. While the size of the uterus may affect the frequency of urination, the amount of urine being excreted also increases. This is important to remember, as runners may notice having to stop more frequently for bathroom breaks while out on a run. Using the restroom "just in case" or holding urine too long may both lead to future risk of pelvic floor dysfunction, such as urinary incontinence. However, limiting fluid intake before or during runs is not advised, as this puts the woman at risk for dehydration. There is a greater need for fluids in general during pregnancy, and even more so with running, due to the loss of fluid through sweating.
Hormones, including estrogen and progesterone, rise during pregnancy to help support the growing fetus, as well as the placenta. Estrogen and progesterone are produced in the adrenals, but during pregnancy, are also produced by the placenta. These hormones, in addition to relaxin, prepare the body for childbirth by increasing laxity in connective tissues. The motherís body also begins to prepare for lactation, an event stimulated by estrogen.
During pregnancy, women demonstrate decreased step length and stride length, increased base of support, and increased double limb support time (time spent on both legs) during walking and running. These physiological changes continue for at least eight to 16 weeks postpartum.
BENEFITS OF EXERCISE DURING PREGNANCY
Physiological changes help prepare the body for pregnancy and delivery. It is equally important to prepare the mind for the changes that will occur during pregnancy, and for childbirth and motherhood in general. Multiple studies show that exercising for at least 30 minutes on most days of the week at a moderate intensity will produce many positive physical and psychological effects, including:
- Increased energy
- Improved mood
- Better sleep
- Decreased incidence of depression
- Increased social connections
- Reduced risk of gestational diabetes
- Lower weight gain during pregnancy
- Easier loss of post-pregnancy weight
Evidence shows that exercise during pregnancy helps preserve or slightly increase a womanís aerobic fitness without risk to the mother or to the developing fetus. By six to eight weeks postpartum, the uterus and vagina have returned to their pre-pregnancy size. It is around this time that women usually return to the OB/GYN for their postpartum check-up. If there are no complications from the delivery, they are typically given a green light to slowly resume their previous level of activity.
In the past, many doctors were hesitant to recommend exercise to pregnant women because little was known about the effects on mom and baby. However, research in the last 10 years overwhelmingly supports exercise during pregnancy. In 2017, the American College of Obstetrics and Gynecology (ACOG) updated its guidelines, not only supporting, but also recommending up to 150 minutes of exercise per week, at a moderate intensity, during pregnancy. The meaning of "moderate intensity" varies from woman to woman. Those who train year-round and who have built up endurance may be able to tolerate faster speeds and longer runs compared to women who do not run as often or at a competitive level. Regardless of level of fitness or running experience, it is important to include at least a 10-minute warm-up before advancing to your typical running pace. Due to the physiological changes of pregnancy, the body needs time to respond to the demands of running through a longer warm-up. Pregnancy weight gain will increase the amount of force that moves through the body due to the high-impact nature of running. With each step, the ground reaction force, the amount of force that travels from the ground up through the body, increases as well. Maintaining strength in the hips, low back, and core can help support the increased load. It may be necessary to decrease the running pace or distance to limit excessive load on joints as pregnancy progresses. Pregnancy is not a time to try something new, like significantly increasing distance or running a marathon for the first time. How much is too much? One conventional method to gauge the correct exercise intensity is known as the "talk test." While running, your heart rate will rise, but you should still be able to carry on a conversation with a friend. In addition, hydration is important. Drinking water before, during, and after exercise is recommended. In general, hydration needs are greater during pregnancy, and this is especially important with exercise, when body temperature rises, and fluid is lost. Just remember, you may need to plan a running route that has more bathroom stops than normal!
Other signs that intensity is too high include:
- Chest pain
- Shortness of breath
- Lightheaded or dizzy feeling
- Calf pain
- Muscle weakness
- Bleeding from the vagina
- Leaking of fluid from the vagina
- Uterine contractions
If any of the above symptoms occur while running, stop immediately and call your doctor.
Pregnancy is a dynamic process, and changes can occur rapidly. Musculoskeletal aches and pains are common. Running may exacerbate this discomfort; however, many women continue to run even with pain or discomfort. Changes in biomechanics, posture, center of gravity, joint laxity, ligamentous laxity, and weight may all contribute to difficulty with continuing to run as pregnancy progresses. Companies have capitalized on the large population of pregnant runners by creating braces and other types of external support devices to help women continue running throughout pregnancy. We recommend consulting with a physical therapist before using any of these supportive products. Most of them are not harmful, but some may be more beneficial than others.
The most common type of support is a lumbar and/or pelvic belt or brace. These typically contain elastic and have a Velcro closure. They are designed to support the spine as pregnancy advances. A disadvantage to this type of support is that long-term use may discourage use of your own muscles to support your spine through reliance on the brace. However, for people who run longer distances, they may be helpful. Another alternative is support shorts, which may also offer compression. Standard shorts work well early in pregnancy, but may not be comfortable with a growing belly due to the compression. Some brands make a type of compression short with a cutout for the belly. These shorts may also aid in circulation, which can be compromised due to laxity of blood vessels and help with varicosities in the legs and pelvic region. As a general rule, any compression garment should not restrict blood flow, especially to the lower abdomen and pelvic region.
Proper footwear for exercise during pregnancy is essential. Women may need greater arch support and cushioning, as ligamentous laxity will affect the feet. In addition to new, supportive shoes, orthotic inserts can also provide additional support and cushioning. As with postural supports, we recommend consulting with a physical therapist before purchasing any shoes and/or orthotic inserts. This will ensure proper type and fit, minimizing the risk of injury.
As stated, exercise is recommended throughout pregnancy. It enhances mood, moderates the physical changes that can occur with pregnancy, and may aid with postpartum recovery. Certain conditions may require special clearance from a physician before you start to exercise, however, or may require you to modify or discontinue your exercise routine. The list below outlines the known precautions and contraindications. If you are experiencing any of these symptoms or conditions, please consult with your obstetrician before starting or continuing to exercise.
- Heart disease
- Lung disease
- Cervical insufficiency/cerclage
- Pregnant with multiples
- Risk of preterm labor
- Placenta previa after week
- Rupture of membranes
- Pre-eclampsia or high blood pressure
- Severe anemia
Being mindful of the changes that occur during pregnancy and the warning signs that you are over-exerting is key to being able to continue to run safely throughout pregnancy. It is okay to slow down your pace, run less frequently, or take more breaks to walk. Do what is comfortable for you. With the proper modifications, you should be able to find your groove out on the road, even if itís a little different than what you were doing before you became pregnant. Be smart, listen to your body, and stop if something does not seem right. Otherwise, enjoy the time you have to breathe, think, and prepare, or just lose yourself in thoughts that have nothing to do with baby or motherhood.
KATE MIHEVC-EDWARDS, PT, DPT, OCS is a Doctor of Physical Therapy with a focus on treating runners and triathletes, a board-certified orthopedic specialist, founder/CEO of Precision Performance & Physical Therapy. A former endurance athlete with thirteen marathons under her belt, Dr. Edwards is also the author of Racing Heart, which chronicles her experience with a genetic heart disease known as arrhythmogenic right ventricular cardiomyopathy (ARVC).
Dr. Edwards is adjunct faculty in the Physical Therapy program at Emory University where she teaches a course titled "The Endurance Athlete" and has been involved in running related research. She has been contributed her expertise to Runners World, Womenís Running and Triathlete magazine and recently published an article in The National Journal of Strength and Conditioning, "Considerations for the Postpartum Runner." She lives in Atlanta with her husband, Brian, son, Andy, and Wiemaraner Austin.
BLAIR GREEN, PT, DPT, OCS is a Doctor of Physical Therapy with a focus on pre/post-natal health and wellness, the founder/CEO of Catalyst Physical Therapy, and a board-certified orthopedic specialist. Known as the "go-to" expert in her field, Dr. Green is also a Polestar-trained Pilates instructor and a Certified Manual Trigger Point Therapist. She serves as an instructor in the Physical Therapy program at Emory University, and as a faculty member for several Physical Therapy continuing education companies.
Dr. Green has previously published a chapter in the textbook, Trigger Point Dry Needling: An Evidence and Clinical-Based Approach, 2nd ed., "Deep Dry Needling of the Hip and Pelvic Muscles." She is professionally involved in the American Physical Therapy Association (APTA) and the Section on Womenís Health. Dr. Green lives in Atlanta with her husband, Greg, and two children, Harrison and Leah.
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