What Causes Protein in Urine During Pregnancy? And What It Means

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If your urine was tested at any point in your life, there would be some amount of protein in it—that’s normal for all of us. In pregnancy, the amount of protein in urine increases naturally, and in some cases, it increases to a point where your healthcare provider might be concerned.

It can be stressful and nerve-wracking if you find out that you have concerning amounts of protein in your urine, or if your healthcare provider needs to do follow-up testing to rule out other conditions connected to protein in the urine.

We reached out to experts to help us understand what it means when you have protein in your urine during pregnancy, when protein in urine may be a problem, and how conditions related to protein in urine during pregnancy are treated.

What Does Protein in Urine Mean?

In a non-pregnant individual, a normal amount of protein in urine would be about 150mg/day. But when you are pregnant, that number can increase to up to 300mg/day.

“Our bodies go through various changes during pregnancy,” says Jee Shim, MD, an OB/GYN at Long Island Jewish Forest Hills Hospital in New York. “One of the normal/expected changes is increased levels of protein in the urine.”

Whether or not your healthcare provider would be concerned with the amount of protein during pregnancy would depend on the amount, says Dr. Shim.

“If the levels are higher than 300mg/day, it will need further evaluation by your OB/GYN doctor,” she explains. “Less than 300 mg/day is considered normal.”

It also depends on where you are in your pregnancy. Elevated levels of protein in urine in early pregnancy may not be as much of a concern as higher levels later on in pregnancy.

“For the most part, having a small amount of protein in early pregnancy (before 20 weeks of pregnancy) is considered either normal or may be indicative of a minor infection in your urine,” says Amy Wetter, MD, OB/GYN at Northside Women’s Specialists, part of Pediatrix Medical Group.

Further investigation of the cause might be indicated in this case, says Dr. Wetter, but it’s not typically something that worries her. On the other hand, elevated protein in the urine after 20 weeks is usually more concerning.

“If the patient is over 20 weeks, my suspicion for preeclampsia is raised and the patient will need to have bloodwork to evaluate her platelets, kidney function, and liver function, and she will also need to collect her urine for 24 hours to see how much is being excreted during that time,” says Dr. Wetter.

Causes of Protein in Urine While Pregnant

Again, protein in urine in pregnancy has different causes depending on whether you're in early pregnancy or later on in pregnancy (greater than 20 weeks pregnant). 

Early Pregnancy

If you have elevated levels of protein in your urine in the first 20 weeks of pregnancy, one possible cause is kidney damage. “Protein levels in urine can increase if the kidneys are not working as they should be, so proteinuria may be a marker for renal disease,” explains Robyn Horsager-Boehrer, MD, chief of obstetrics and gynecology at UT Southwestern Medical Center.

Certain conditions may cause your kidneys to be strained. “Sometimes women have unknown underlying health conditions like hypertension, diabetes, lupus,or kidney disease, which can cause significant protein in the urine,” says Dr. Wetter.

Elevated protein in urine during early pregnancy can have less worrisome causes, too. A mild urinary tract infection or dehydration can cause elevated protein in your urine as well, says Dr. Wetter.

After 20 Weeks

After the midpoint in your pregnancy, the main concern with elevated protein in your urine is that it may indicate preeclampsia, a serious condition in pregnancy that can put both your and your baby at risk for complications.

“After 20 weeks of pregnancy, protein in the urine must be evaluated for the possibility of preeclampsia,” says Dr. Wetter. “Not everyone with proteinuria will have or even go on to develop preeclampsia, but this condition is the most important to diagnose as it can lead to very serious consequences for both mom and baby.”

It’s important to understand that elevated protein in the urine after 20 weeks isn’t evidence alone that you have preeclampsia. According to the American College of Obstetricians and Gynecologists (ACOG), elevated blood pressure—readings above 140/90 mm Hg at least twice—must be present for you to be diagnosed with preeclampsia.

Coupled with high blood pressure, having either elevated levels of protein in your urine or severe preeclampsia symptoms is what might constitute a diagnosis.

Risks of Protein in Urine While Pregnant

The risks of protein in urine during pregnancy depend on what is causing the elevated levels. Some of the causes are less serious than others, or easier to treat and resolve.

Most of the causes of protein in urine in early pregnancy do not have serious risks. “If protein is found in your urine before 20 weeks, it is less likely to be a concerning symptom,” says Maggie Bolton, CNM, ARNP, clinical director of Quilted Health. “However, it should still be evaluated.”

Increased protein in urine after 20 weeks is where there may be serious risks to you or your baby, especially if coupled with elevated blood pressure, and symptoms like blurred vision, swelling, and shortness of breath. In this case, you may have preeclampsia, and you will need to be monitored and treated.

“Preeclampsia is a progressive disorder which can affect many body systems,” Bolton describes. “It is caused by the placenta and the pregnant person’s vascular system and in most cases, it resolves quickly after the birth. Your provider will want to monitor you very closely, and may even recommend induction depending on the severity of the condition.”

Symptoms of Protein in Urine While Pregnant

Unless you are dealing with a urinary tract infection, most of the time that you have protein in your urine during pregnancy, you will not have many obvious symptoms. However, if you are experiencing preeclampsia, you may have some noticeable symptoms, along with an elevated amount of protein in your urine.

Early signs of preeclampsia may include retaining more water than usual, increased blood pressure, along with protein in your urine. You may notice rapid weight gain along with swelling. Other signs of preeclampsia may progress to headaches, blurry vision, stomach pain concentrated on your right side, dark spots in your vision, and shortness of breath.

How Protein in Urine Is Detected

You will usually get a urine test at your first prenatal visit. This is usually a “dipstick,” where you pee in a cup, and your urine is analyzed by using testing strips that can detect specific indicators.

If your healthcare provider is concerned about your protein levels, or if you have other symptoms, such as symptoms of preeclampsia, a more thorough urine test may be ordered.

“If your blood pressure starts to rise or you develop concerning symptoms (right upper quadrant, severe headaches that don’t go away with medication, or changes in your vision) in later pregnancy, your provider will recommend testing your urine for protein,” says Bolton.

The “gold standard” for testing urine in pregnancy is a “urine protein to creatinine ratio,” Bolton explains. This requires a urine sample that will get sent to the lab. Other possible tests include “albumin to creatinine ratio” and the “the 24-hour urine collection” test.

Treating Protein in Urine While Pregnant

Treatment for urine in pregnancy will depend on what the cause is, and where you are in your pregnancy.

In early pregnancy, protein in urine often indicated a UTI or other kidney issue. Usually, this can be treated simply.

“If I have a patient with a small amount of protein in their urine and that patient is otherwise healthy with no chronic medical problems, my first step is to reassure them, encourage them to drink plenty of water if dehydration is suspected, and then also send a urine culture to evaluate further,” says Dr. Wetter.

If you have other conditions that are causing protein in your urine, such as high blood pressure, diabetes, or kidney disease, you will need to get a thorough history taken as well as a physical examination, says Dr. Wetter. Special attention will need to be paid to your weight, as well as your blood pressure, she says.

If you are later in your pregnancy and it’s determined that you have preeclampsia, you will need to be treated promptly and thoroughly for this, so that your health, as well as the health of your baby, is protected.

If you are more than 37 weeks pregnant and are diagnosed with preeclampsia, induction and delivery of the baby will likely be recommended. If you are less than 37 weeks, you will probably be put on bed rest, and you may be given medication like magnesium sulfate to prevent seizures. The health of you and your baby will be closely monitored until you give birth.

Preventing Protein in Urine in Pregnancy

Most cases of protein in urine during pregnancy can’t be prevented. Conditions such as preeclampsia are often inherited disorders. Underlying conditions that may cause protein in urine to increase, such as diabetes, lupus, and hypertension, may also be genetic or have complex medical and autoimmune causes.

There is some evidence that you can lower your risk of developing preeclampsia by controlling your blood sugar and blood pressure, exercising regularly, decreasing salt and caffeine intake, and making sure to get enough sleep.

There are some indications that taking a baby aspirin daily can decrease your risk of developing preeclampsia by 15%. You should talk to your healthcare provider before taking baby aspirin.

When to Seek Medical Attention

If you suspect that something is off, it's important to talk with your healthcare provider sooner rather than later. “There are many signs and symptoms to be aware of if you have protein in your urine during pregnancy,” says Dr. Wetter. “Most of these signs and symptoms are associated with preeclampsia as this diagnosis is generally what we are most concerned about developing.”

Signs of preeclampsia to look for include elevated blood pressure detected at home or at your healthcare provider’s office, sudden weight gain, swelling in your extremities or face, nausea or vomiting, vision changes, upper right adnominal pain, and severe headaches.

“Many times, patients have related to me that they just started feeling off without a specific symptom, therefore I implore women to listen to their bodies and if they feel something is wrong, to call their healthcare provider,” Dr. Wetter advises.

A Word from Verywell

If you get the results of a urine test and your protein levels are elevated, it’s understandable that you may feel worried. First, remember that pregnant individuals often have higher levels of protein in their urine and that usually only levels over 300mg/day are cause for concern.

If your levels are elevated after 20 weeks, the greatest concern is preeclampsia, but elevated protein levels alone do not mean you have preeclampsia. It’s important that you stay in touch with your healthcare provider, as they will want to conduct diagnostic tests to understand what is going on.

Remember that even if you develop preeclampsia, your medical team will do their due diligence to ensure the best outcome for you and your baby.

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6 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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