Swelling during pregnancy occurs for many reasons, though it is primarily because maternal blood volume increases by 50%. This increase in blood volume increases total body fluid volume and can account for up to 25% of weight gain during pregnancy.
This “water-weight” is lost soon after delivery. However, this swelling during pregnancy can cause a lot of discomfort, especially during the hot summer months.
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Swelling during pregnancy can result in large amounts of fluid pooling in the lower extremities … literally liters! This fluid retention also causes swelling in many other parts of the body:
During the summer months, swelling during pregnancy can be severe. However, as will be discussed, if the swelling is not a result of pregnancy-related complications, there are ways you can keep this swelling to a minimum.
First, let’s discuss what pregnancy complications cause swelling:
The reason it is important to discuss abnormal causes of swelling is because these conditions must be evaluated and managed promptly by your prenatal care provider:
- Toxemia (preeclampsia, gestational hypertension) This is a common problem, particularly among young women having their first baby. If you have ankle swelling (particularly if accompanied by swelling in the hands and face), a thorough evaluation must be done to be certain your swelling is not related to toxemia.
- Phlebitis (vein inflammation) or blood clots: Though rare, these medical complications can also cause swelling in the ankles and legs. This form of swelling is often associated with redness, tenderness, pain etc. and must be evaluated immediately to be sure this problem is not the result of a vascular problem. The evaluation will include a physical exam, ultrasound and additional studies as deemed necessary. These vascular conditions must be diagnosed promptly and require treatment.
- Medical problems unrelated to pregnancy: Maternal medical problems …. kidney disease, etc. can also cause swelling. A thorough medical history and physical examination at your first prenatal visit is required to screen for these underlying medical problems.
*Assuming the above conditions (which are not all-inclusive) have been excluded by your prenatal care provider, the cause of your swelling is likely the result of “normal” physiologic changes associated with pregnancy.
What is considered “normal” swelling during pregnancy?
To answer this question it is important to have a basic understanding of the changes in maternal circulation during pregnancy. Having this information helps make sense of the suggestions that will be offered at the end of this article.
As a rule, compliance with medical advice is far better when there is a scientific explanation or reason for why health problems or symptoms occur.
“Normal” swelling during pregnancy occurs when the result of hydrostatic pressure within the blood vessels becomes greater than the osmotic pressure to keep fluid in your vessels.
As the fluid in your blood is allowed to leak or seep out of the vessels, it is sequestered in body tissues surrounding blood vessels. This is the swelling we observe and is the reason you may notice “pitting edema” when you press on your swollen ankles. This pitting resolves as the fluid redistributes.
Blood flow to the lower extremities is a high pressure system. Your arteries pump blood away from your heart. In additions, the forces of gravity push blood down when standing.
The low pressure venous system is unable to effectively oppose this arterial pressure and return blood back to the heart. Veins use valves and muscular contractions to pump blood up your legs and back to the heart.
This is why simply elevating your legs can alleviate swelling. By just elevating your legs at night you can literally have the swelling completely resolved by the next morning.
Why does swelling resolve overnight?
There two main facts that best explain why swelling during pregnancy diminishes overnight. The first is the physiology behind swelling and the second is the clinical observation:
- Physiology: The vascular pressure gradients that lead to the extravasation of fluid into the tissues is the physiology. This being said, the physiologic solution takes care of itself when you lie down to sleep at night. It is simply because your legs and kidneys are at the same level as your heart. Fluid in the tissues flows back into your blood vessels. Your blood returns with this fluid to your heart and is then sent to your kidneys where the fluid is filtered out of your body all night long.
- Clinical Observation: So know that the fluid is able to be mobilized back to your heart what is the clinical observation? Most new moms or pregnant women know the answer to this. Urinating frequently throughout the night. The increased perfusion to the kidneys allows the extra fluid to be filtered out, only to start the entire process over the next day when your feet hit the ground in. So elevate your legs whenever possible!
I am hopeful this explanation helps you to understand why swelling increases during the day and resolves at night. It is very important to remember that there are times when swelling occurs for other reasons that may be related to pregnancy complications.
It is not to say these complications do not have medical solutions, it is simply important that they are recognized and addressed to avoid worsening medical problems.
How to prevent swelling during pregnancy:
- Hydration: Though this suggestion may seem counter-intuitive, drinking water actually helps mobilize fluid out of the tissues. Drinking water helps flush out toxins and decreases water retention for a number of reasons. The fluid or edema, stored in tissues outside the bloodstream, as discussed, have to be mobilized back into the circulation. As noted above, this can literally be liters of fluid stored in your legs.
- Leg Elevation: Helps to promote blood flow to and from your lower extremities and ultimately to your kidneys to where excess fluid is removed (as previously discussed).
- Compression stockings: to prevent the pooling of blood in your legs. These stockings MUST be properly fitted. Compression stockings are fit by your provider or a medical supply company to apply the proper amount of compression. It is important that the amount of pressure is not too high as it can be constrictive and cause worse swelling. Though you can order compression stockings through our amazon affiliate links, you MUST discuss using compression stockings with your prenatal provider. If you have a problem with varicose veins this will likely be addressed by your provider as a preventive measure before swelling starts to occur.
- Moderate Exercise: (If cleared by your prenatal care provider) promotes circulation and can help prevent blood clots. If you are required to be on your feet from the moment you leave the house in the morning until you return at night, you can be almost assured you will observe a significant amount of ankle swelling during the morning until evening not only will you very likely observe pitting edema as previously discussed, you will also observe swelling around the constrictive band at the top of your socks. Many women find they cannot fit into your shoes during the third trimester due to swelling/fluid retention.
- Reduce Salt Intake: At least avoid salting your food. Most food is prepared with more than enough salt.
- Avoid Restrictive Clothing: This acts like a tourniquet, obstructing the flow of blood back to the heart. Fluid then leaks out of the circulation into the surrounding tissues.
- Avoid Prolonged Standing: Especially standing still as this only allows blood to pool in your lower extremities. By moving around your muscles contract and along with the valves in your veins will promote the return of blood to your heart to be perfused through your kidneys and removed.
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If you want to learn more about osmotic pressure with opposes hydrostatic pressure in blood vessels, it can help to further understand why edema occurs. Visit the following page for more information: OSMOTIC PRESSURE