Myth 1: “Exercise will overheat the baby.”
Reality: A healthy woman can exercise without overheating. It is best to wear loose-fitting clothing and stay hydrated to keep the body cool. Avoiding hot baths or saunas is also wise because the heat can raise the body’s core temperature. While there is some risk to the fetus when exposed to extreme heat during pregnancy, simply because the mother feels hot does not mean the baby is in danger. An increase in thermoregulation occurs during pregnancy, which allows excess heat to be pulled away from the fetus, offering protection. A study examined this myth and concluded there is no reason for women to avoid land or water exercise (Ravanelli et al., 2018).
Myth 2: “Exercise will tangle the umbilical cord.”
Reality: No evidence exists that exercise increases the risk of a tangled umbilical cord. A nuchal cord (umbilical cord around the neck) can be dangerous. However, it is usually not and is not linked to physical activity.
Myth 3: “The heart rate cannot rise above 140 beats per minute.”
Reality: When ACOG released recommendations in the 1980s, little research was available on prenatal exercise. In the mid-90s, ACOG revised its heart rate (HR) recommendation to the rate of perceived exertion (RPE) scale. Since HR naturally increases and fluctuates during pregnancy, it is an ineffective measure of exertion. However, the myth that a pregnant woman should not raise her HR above 140 bpm is still widely accepted as fact.
Women are encouraged to listen to their bodies and avoid getting too high on the RPE scale. For example, on a scale of 1-10 (“1” being easy and “10” being exhausting), it is safe to exercise at a 6-7 but could potentially become dangerous if sustained at a 9-10. The HR is likely in a safe zone if the expectant mother can talk without becoming breathless or faint.
Myth 4: “Working out will cause a miscarriage.”
Reality: There is no evidence suggesting that exercise leads to miscarriage. At the same time, there are many proven benefits of exercise for mothers and babies. The first trimester of pregnancy has a higher risk of miscarriage, which is unrelated to exercise. Physical activity is proven to relieve stress, and there is a link between psychological stress and miscarriage (Qu et al., 2017).
Myth 5: “Do not lift more than 25 lbs.”
Reality: This is the kind of conservative, generalized recommendation commonly given to pregnant women. However, this recommendation needs to be more specific. Women’s bodies and fitness backgrounds differ, so broad rules are rarely accurate.
Myth 6: “Avoid exercises like squats and lunges because of the increased pressure on the pelvic floor.”
Reality: If squats and lunges feel comfortable, and there are no other contraindications, they are safe for pregnancy. They are effective exercises to burn calories, strengthen lower body and core muscles, improve balance, and prepare for labor. As a precaution, it may be wise to squat with a sturdy chair placed underneath the hips or lunge close to a wall for help with balance. Engage the inner thighs, core, and pelvic floor muscles during the movement for added benefit and support.
Myth 7: “Do not do pushups, plank, crunch, or other core exercises because of the strain on the abdominals, which can cause them to separate.”
Reality: Most abdominal exercises are considered safe when performed correctly. Diastasis recti (separation of the rectus abdominis along the linea alba) is common in pregnancy from hormonal shifts and the weakening and overstretching of the abs. Many women mistakenly avoid core exercises as a precaution while pregnant and postpartum. However, safe, modified core exercises can decrease the risk of diastasis recti, while abstaining from ab exercises may lead to muscle atrophy and weakened core muscles. Research shows that gentle core exercises performed consistently during and soon after pregnancy, including abdominal planks, bracing, and curl-ups can decrease abdominal separation and should not be avoided as previously thought. More research is needed to fully understand the best methods. However, preventing diastasis through physical activity, weight management, and core strength is a safe strategy.
Myth 8: “Pregnant women should not lie on their backs.”
Reality: After the first trimester, lying flat on a hard surface for an extended period should be avoided. It can cause symptoms like dizziness, nausea, shortness of breath, increased pulse and decreased blood pressure because of added pressure on an enlarged vein called the vena cava, which returns blood to the heart. However, simply sitting up or rolling onto the left side can ease symptoms and prevent possible harm. Lying slightly inclined or on a stability ball are comfortable alternatives. As long as an exercise feels comfortable, it is likely safe to continue.