Urinary tract infections, high blood pressure (preeclampsia), and kidney problems are common causes of protein in your urine when you’re pregnant. They all require medical attention and typically respond well to prompt treatment.

You may wonder why your doctor asks you to pee in a cup at each of your prenatal visits. Your urine is actually a pretty useful tool when it comes to understanding your overall health.

For example, a single urine sample can tell your healthcare provider if you’re dehydrated or have an infection. It can also show markers for more serious health issues, like diabetes.

Protein in the urine (proteinuria) may be a sign of anything from stress to fever to preeclampsia, which is a condition present in an estimated 4 percent of pregnancies in the United States.

Preeclampsia can pose some serious risks for both you and baby. Here’s more about how your urine may help diagnose these issues and how they’re treated.

Your kidneys are hard at work during pregnancy (and all the time, really). They filter the waste products in your blood all while keeping things, like proteins, that your body needs to thrive. After being filtered, the waste is released into your urine.

If protein makes its way to the urine, that’s usually because something isn’t functioning quite right in the kidneys.

Outside of pregnancy, protein in the urine may be temporarily elevated due to:

  • emotional or physical stress (strenuous exercise, for example)
  • dehydration
  • fever
  • exposure to extreme temperatures

But there are other situations where protein in the urine may be a sign of something more.

Before 20 weeks of pregnancy, proteinuria is sometimes referred to as chronic proteinuria.

It may be due to underlying issues with the kidneys or other health conditions that aren’t necessarily related to your pregnancy, like heart disease. Infections (urinary tract infection, for instance) may also elevate the protein levels in your urine and require medical attention.

After 20 weeks, on the other hand, doctors look more closely at protein as a possible indicator of preeclampsia. This condition is marked by high blood pressure and may cause damage to organs, particularly the liver and kidneys.

HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count) is a similar, yet more severe form of preeclampsia that may develop along with preeclampsia or all on its own.

Without treatment, both conditions may lead to serious complications for both you and baby.

First, it’s important to understand that you do excrete more protein in your pee during pregnancy than when you aren’t pregnant. Double the amount, actually — increasing from up to 150 milligrams/day (mg/d) pre-pregnancy to up to 300 mg/d during pregnancy.

The reason for this jump? Increased blood volume, which taxes the kidneys more than normal. So pregnancy itself is a risk factor for protein in the urine.

You may also be at a higher risk if you have any chronic conditions before your pregnancy or if you have a family history of conditions that impact the liver and kidneys.

Otherwise, risk factors for preeclampsia include things like a history (personal or family) of preeclampsia with previous pregnancies, this being your first pregnancy, and being over age 35.

Other risk factors:

Research shows that non-Hispanic Black women are more likely to go into pregnancy with chronic hypertension, which is itself a risk factor for preeclampsia. However, this may be due to inequities in healthcare rather than any factors associated with race itself.

A reading of more than 300 mg/d of protein in your urine is considered high. Beyond that, you may or may not have any symptoms of protein in your urine. You may not even realize anything is off until your next prenatal appointment when your urine is tested.

Otherwise, symptoms may be similar to those of kidney disease:

  • swelling in the ankles, wrists, or eyes
  • burning sensation while urinating
  • increased urination (although this is common in pregnancy in general)
  • back pain (also often a normal part of pregnancy)
  • foamy or brown/bloody urine

What accompanying symptoms are particularly worrisome?

There are additional signs you’ll want to watch that indicate the cause of protein in your urine may be more serious.

Symptoms of preeclampsia include:

  • headaches, particularly severe headaches
  • blurry vision or other vision issues (loss of vision, light sensitivity)
  • pain in your abdomen (on the right side, under your ribs)
  • nausea/vomiting
  • shortness of breath
  • lowered urine output

And while it’s normal to gain weight during pregnancy, be sure to alert your doctor if you experience sudden weight gain. A gain of more than a few pounds in a week or significant swelling in the hands or face are other potential warning signs.

The initial test of your urine at your doctor’s office is called a dipstick test. A strip is inserted into your urine and chemical patches react by changing color depending on the amount of protein detected. The range of results goes from + to ++++ or low (+1) to high (+4).

If your result is above normal, your doctor may give you a 24-hour urine protein test to monitor your levels more closely over a longer period. Your urine is collected throughout a day’s time and is analyzed. Morning urine is usually excluded from the test. A high result is considered abnormal and a possible sign of kidney or other health issues.

If only trace amounts are observed, your doctor may or may not order further testing. Or your doctor may use other signs and symptoms to move forward.

Trace amounts of protein can enter the urine if they’re too small to be filtered by the kidneys. In most cases, though, the protein molecules are usually too large to be filtered out.

Protein in the urine alone doesn’t mean you have preeclampsia. In fact, you can have preeclampsia and not have any protein in your urine. Doctors must look at various signs and symptoms to make an accurate diagnosis.

Again, preeclampsia usually occurs in the second half of pregnancy, after week 20. It can rarely occur earlier or occasionally in the postpartum period.

Signs and symptoms include:

  • low platelet count
  • issues with liver function
  • other signs of kidney problems
  • abdominal pain
  • pulmonary edema (fluid in the lungs)
  • new headaches
  • new vision issues

Doctors consider a blood pressure reading higher than 140/90 mm Hg to be high during pregnancy. But — again — a high reading doesn’t always mean you have preeclampsia. Your doctor will look at the trend in your numbers compared to your baseline to help with diagnosis.

Testing might include:

  • Blood tests to evaluate your liver function, kidney function, and the number of platelets in your blood.
  • 24-hour urine collection to observe protein in your urine throughout an entire day.
  • Ultrasound to monitor your baby’s development and the amount of amniotic fluid in your uterus.
  • Nonstress tests or biophysical profiles to evaluate your baby’s health status. These can reveal baby’s heart rate with relation to their movements and their breathing and muscle tone.

Trace amounts of protein may not be an issue and can be monitored by your healthcare provider. For higher amounts, treatment will depend on the cause.

In earlier pregnancy, when causes may be due to underlying chronic health conditions, you’ll work with your doctor to find the appropriate treatment that’s safe for both you and your baby.

Infections, like UTIs, can be safely treated with antibiotics. Other complications may need more monitoring. This may mean seeing specialists outside of your OB-GYN.

Preeclampsia is treated in a variety of ways. Your treatment will depend on how far along you are, how severe your condition is, and how you and baby are faring. The most effective treatment for preeclampsia is delivery, though that may not be possible if you’re not far enough along.

Other treatments:

  • Frequent monitoring. Your doctor will likely have you come in for testing more regularly to monitor changes in your health or your baby’s health.
  • Blood pressure medications. Antihypertensives may be used to lower blood pressure when it’s particularly high. There are options that are safe during pregnancy.
  • Bed rest. Doctors used to regularly prescribe bed rest to those with preeclampsia. Opinions are mixed on how effective this is, though. Generally, bed rest is no longer recommended due to an increased risk of blood clots and other social and economic factors.

Again, for cases of severe preeclampsia, delivery may be the only option. If early delivery is needed, your doctor may give you an injection (or two, 24 hours apart) of corticosteroids to help mature your baby’s lungs.

If you have HELLP syndrome, your doctor may prescribe corticosteroids to help with your liver and platelet function. This can help you stay pregnant longer to let your baby develop and may even help develop your baby’s lungs if early delivery is necessary.

Without treatment for preeclampsia, you may have an increased risk of complications like placental abruption, severe bleeding, stroke, or seizures. In some cases, preeclampsia can be fatal. So, it’s important to work closely with your healthcare provider if you show any of the signs.

Since protein in the urine in early pregnancy is associated with preexisting conditions, some of which are genetic, you can’t necessarily do anything for prevention. There’s no current evidence to suggest anything clear-cut that will prevent preeclampsia.

However, it’s always a good idea to take certain preventative measures before becoming pregnant, especially if you have preexisting conditions. Check in with your doctor about what a healthy weight is for you, try to maintain a diet with plenty of lean protein and vegetables, and make sure your blood pressure is well managed.

And if you’re already pregnant, doctors do suggest a couple of methods to potentially lower your risk of developing preeclampsia:

  • Taking low-dose aspirin if you have a history of preeclampsia, pregnancy with multiples, chronic high blood pressure, or other health issues, like kidney disease or diabetes. The recommended dosage is 81 milligrams starting at week 12 in pregnancy. However, since aspirin is available over-the-counter, we do need to add: Don’t do this without your doctor’s guidance.
  • Taking calcium supplements if you have a calcium deficiency may also prevent preeclampsia. However, it’s rare in developed countries to have a deficiency severe enough for this method to provide a notable benefit.

Remember: If this is your first pregnancy, you’re at a higher risk of developing preeclampsia. And you may be more likely to experience this complication if you had it in a previous pregnancy.

Speak with you doctor to see if there are prevention methods that may be appropriate for you given your health history and risk factors.

No matter where you are in your pregnancy, it’s best to go to all your prenatal appointments. Early detection is key for treating the conditions associated with protein in the urine.

Be open and honest with your doctor about your concerns and with any symptoms you’re experiencing. It can be a stressful time, but your doctor is there to help you navigate your way to a healthy pregnancy.