A guide to learning about your bodily changes during pregnancy – Cardiorespiratory system!
Congratulations You’re Pregnant! Your body already has been and is going to continue to change so much in the next 9+ months!
We wanted to write a series of blogs to provide you with an overview of the bodily changes you will experience during pregnancy and list some helpful tips on managing your expectations in the coming months.
Here is a short breakdown of the upcoming changes to look forward to! Remember to check out the other pregnancy and pelvic health blogs.
Disclaimer: Each person and pregnancy is going to be unique! This is intended to be a brief summary to give a general picture of the physiologic changes associated with uncomplicated pregnancy. This is not meant to be an all-encompassing list or medical advice of any kind.
At any time, if you have any medical concerns or specific questions, please ask your healthcare provider.
CARDIORESPIRATORY SYSTEM: This system consists of your heart, arteries, veins, and blood, which is responsible for transporting oxygen, nutrients, and much more to you and the baby. Here is a link to a short video to review the cardiopulmonary system if you would like more information.
- Heart:
- To keep up with the demand for nutrients and oxygen, the heart muscle can enlarge, heart rate can increase as much as 20%, blood volume can increase by 30-50%, and total amount of blood pumped out of the heart (cardiac output) can increase by 50%.
- Blood pressure can also be affected! This is due to increased relaxation of the muscles in the arteries and veins. The blood pressure can drop when lying down, and can cause lightheadedness and/or fainting when changing positions. Also, though this is rare (only occurring in 10% of women) hypotension syndrome can occur in a laying down on your back. If you are experiencing any symptoms, like faintness, lightheadedness, dizziness, nausea, agitation, and even fainting, please consult your healthcare provider.
- Blood changes:
- Red blood cells mass can even increase 20-30%. This happens in conjunction with an increase in blood plasma volume. And although red blood cells mass is increasing, the overall blood plasma increases much faster, leaving less iron present, physiologic anemia is possible. If you are experiencing any symptoms of anemia, like lightheadedness or fatigue, please consult your healthcare provider to see if iron supplementation is appropriate.
- It is important to note that a blood component called plasma fibrinogen, a clotting factor, can also increase up to 50%. This is meant to help reduce blood loss during delivery, but it can increase your risk for developing clots during your pregnancy.
- Symptoms of a blood clot are; pain, redness, or swelling in a leg, such as a calf area, increased pain with walking, skin is warm to the touch, or veins that appear larger on legs than usual. If you are experiencing these symptoms, please consult your healthcare provider.
- These cardiovascular changes can also affect you and the baby during exercise! While there are guidelines for safe exercise, each person is unique and each pregnancy has its own set of circumstances. The type, intensity of exercise, and a person’s prior level of exercise are all factors one should take into account when it comes to exercising during pregnancy. Here is a form that you can fill out, Get Active Questionnaire for Pregnancy, to determine if continuing with exercise is appropriate or if you need to consult your medical provider. Please consult your physician if you have any concerns. Also, here are some suggestions for safely adapting exercise throughout pregnancy.
- Exercise intensity can be measured/limited with the “talk test”, keeping the ability to keep a conversation throughout your workout. Read our review of the recent pregnancy guidelines here. Please consult your medical provider for further guidance with exercise throughout your pregnancy.
- Discontinuing contact sports or activities at your second trimester.
- Respiratory System:
- Overall, lung volume can increase up 30-50%, with oxygen consumption increased by 20%.
- Due to an increase in estrogen systemically, the mucous membrane of the upper respiratory tract becomes more vascular, which can cause nasal and sinus stuffiness, nosebleeds, and even vocal changes.
- Due to the growing baby and physical or postural changes, particularly in the later second and third trimester, it can become difficult to breathe! To accommodate the growing baby, the diaphragm (main breathing muscle under the ribs) can lift up to 4 cm and the lower ribs tend to flare. Rib pain and even difficulty breathing deep due to increased congestion of abdominal organs and uterus is very common.
What you may look like?
- You may see some darkening and/or enlarging of your veins due to the increased blood flow. This is very normal to happen throughout your abdomen and legs. This may go away after delivery, but do not worry if some of these changes are permanent.
- Most of these cardiorespiratory changes are not visible from the outside, so be encouraged to speak up to your healthcare provider if you are experiencing any of these changes.
What you may feel?
- With these cardiovascular changes, you may feel more lightheaded or shortness of breath during or even after physical activity/exertion. There are no specifics given to a pregnant person surrounding exercise, as every person is unique, and the health of the mother and baby are most important.
- You may experience lightheadedness or shortness of breath with everyday and/or exercise activities. With any daily or exercise activities, make sure to adjust intensity and allow for breaks when needed. This is typically what healthcare providers mean when they say, “Listen to your body.” Slowing down is necessary at times.
- If you are experiencing rib pain, talk to your healthcare provider, as physical therapy or other interventions may help with this.
- If you are experiencing any of the symptoms of a blood clot, listed above, call or visit your healthcare provider as soon as possible.
- Physical activity is shown to be VERY safe and VERY effective for improving many health aspects of the pregnancy journey, both for the mother and the baby, however, each pregnancy is different. Please consult your healthcare provider with any questions, but physical activity should be encouraged in most cases. It is more detrimental not to exercise during pregnancy, however, if there is a medical condition or status that does not allow this, give patience and trust that rest may be needed and better for both you and your baby at this time.
- If you were an avid exerciser prior to pregnancy, you also may feel like you can’t push quite to the same intensity or level as prior to pregnancy. These changes may make you feel discouraged, however, the immense change and demand on your body is undeniable. These demands may mean temporary change and shift in mindset so health is prioritized for both mom and baby.
Resources
Since these musculoskeletal and cardiovascular physiologic changes can and will impact exercise, it’s important to start or continue with exercise safely. The Get Active Questionnaire For Pregnancy is a form you can fill out to see if exercise is safe for you to continue or start during pregnancy. Your provider can best determine which level you can begin to exercise at and may use this form to get you started. So good luck exercising!
References
- The American College of Obstetricians and Gynecologists. (2016). Your pregnancy and childbirth: Month to month. Revised 6th Edition.
- BruceBlaus, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
- Davenport, M. H., Neil-Sztramko, S., Lett, B., Duggan, M., Mottola, M. F., Ruchat, S. M., Adamo, K. B., Andrews, K., Artal, R., Beamish, N., Chari, R., Forte, M., Lane, K. N., May, L., Maclaren, K., & Zahavich, A. (2022). Development of the Get Active Questionnaire for Pregnancy: breaking down barriers to prenatal exercise. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme, 47(7), 787–803. https://doi.org/10.1139/apnm-2021-0655
- The user name listed is qimono. It also states “Free for commercial use No attribution required”., CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
- https://vancouver.ca/files/cov/par-q-plus-form-for-pregnancy-before-exercising.pdf via Active Living During Pregnancy: Physical Activity Guidelines for Mother and Baby © 1999. Available from the Canadian Society for Exercise Physiology, www.csep.ca