Protein in Urine During Pregnancy: 3 Major Causes

The fact that our kidneys filter the blood is well understood. They have microscopic blood arteries called glomeruli, which function to reabsorb blood protein and eliminate waste in the urine. However, the protein may seep into your urine if your kidneys are not functioning properly. Proteinuria 1is the medical term for this excessive protein in the urine. Proteinuria is also said to occur when your body produces an excessive amount of protein depending on how much protein is taken during meals.

Chronic proteinuria is the term used to describe protein in your urine throughout the first 20 weeks of pregnancy. However, doctors become more interested in protein in urine during pregnancy, especially after 20 weeks of pregnancy. Because it could be a sign of preeclampsia, a dangerous medical condition. Preeclampsia is mostly recognised by the presence of protein in urine during pregnancy.

Protein in the urine (proteinuria) could indicate anything from pre-eclampsia 2to stress to fever. Commonly, there are no early signs of kidney disease. One of the initial symptoms could be protein in your urine. During a normal checkup, your doctor may detect proteinuria on a urine test.

1. Causes of Protein in Urine During Pregnancy

During pregnancy, your kidneys are working hard. All the while, they keep things like proteins that your body needs to survive, filtering the waste items in your blood. The waste is filtered and then released into your urine. Protein in urine during pregnancy typically indicates a problem with the kidneys’ ability to operate properly.

Outside of pregnancy, protein levels in the urine could momentarily increase because of the following :

  • The stress of either the mind or body (strenuous exercise, for example)
  • Fever
  • Exposure to high temperatures
  • Dehydration

Protein in your urine, however, may also be a symptom of something else in other circumstances.

It might be caused by underlying renal problems or other medical illnesses, such as heart disease, that aren’t necessarily connected to your pregnancy. Your urine’s protein levels may also increase due to infections (such as a urinary tract infection, for example), necessitating medical attention.

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Image by lisa runnels from Pixabay/Copyright 2014

On the other hand, after 20 weeks, medical professionals pay closer attention to protein as a potential sign of preeclampsia. High blood pressure is a defining feature of this illness, which has the potential to harm many organs, especially the liver and kidneys.

Similar to preeclampsia but more severe, HELLP syndrome (hemolysis, increased liver enzymes, and low platelet count) can appear either concurrently with preeclampsia or independently.

Both illnesses have the potential to cause major issues for you and your baby’s health if left untreated.

2. Normal Urine Protein Levels

While the excretion of urine protein is 150 mg/d in healthy women who are not pregnant, it can reach 300 mg/d during a healthy pregnancy. This is related to an increase in blood volume and glomerular filtration rate. But in hypertensive pregnancy, protein in urine during pregnancy greater than 500 mg/d is crucial for diagnosing preeclampsia.

3. Kidney Disease

Any ailment that impairs your kidneys’ ability to function is referred to as a kidney disease resulting in kidney dysfunction. Blood filtration and blood pressure control are important functions of our kidneys.

While it is possible for kidney function to diminish quickly, kidney disease typically takes place over several years. Because of this, renal illness seldom manifests itself during pregnancy. The majority of the time, it is only the discovery of a pre-existing condition or a symptom of another pregnancy-related condition.

3.1) Symptoms of Kidney Disease

Kidney disease has minimal symptoms, especially in the first stages. It will progress if it is not identified and treated at the earliest.

Advanced kidney disease symptoms include:

  • Ankle swells.
  • Swollen eyes.
  • Vomiting or the feeling that you are about to vomit
  • Fatigue and insufficient energy
  • Reduced ability to taste.
  • Reduced appetite
  • Respiration difficulty.
  • Pee with foam or froth. Due to the presence of protein in the urine
  • Leg pains.
  • Bad sleep.
  • Reduced urine production
  • Chronic itchiness.
  • High blood pressure

Chronic kidney disease is a permanent condition. The diminished function of the kidneys, however, may frequently result from another underlying medical condition.

If you have kidney disease, your doctor will seek to identify the root reason for your decreased kidney function and treat it to help your kidneys perform more effectively once again.

Dietary modifications can also aid to improve kidney function and halting additional harm. Dialysis is required if kidney disease results in total renal failure. Patients with kidney failure are typically advised to completely avoid becoming pregnant because it is a risky condition. Fortunately, it would be incredibly unlikely for this to happen during pregnancy.

4. Urinary Tract Infection (UTI)

An infection of the urinary system with bacteria is known as a UTI3. Infection of the bladder is another name for it.

If the infection is not treated, it may spread to the kidneys, resulting in early labour and low birth weight and thereby hindering the baby’s development. Eight glasses of water a day, completely emptying your bladder after peeing, abstaining from douching, blotting with toilet paper rather than wiping after urinating, and wearing cotton underwear that you replace every day can all help in preventing a minor infection which may lead to UTI.

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Photo by CDC on Unsplash/Copyright 2021

Increased uterine pressure on the bladder and urinary system puts pregnant women at a higher risk for UTIs. This pressure might result in an obstruction that prevents the bladder from completely emptying, leading to infection. Pregnancy hormones alter the urinary tract, which facilitates bacterial spread and illness. The diagnosis of UTI can be made by collecting a urine sample and analyzing it by urine culture.

4.1) Symptoms of a UTI

  • Discomfort while urinating, such as pain or burning.
  • Feeling that your bladder is partially empty.
  • Urine with blood in it.
  • Urine seems cloudy due to the presence of protein in the urine.
  • Urine with a foul odor.
  • Leaking of urine
  • Pain while having sex.
  • Lower abdominal pain.
  • Sweating, fever, or chills
  • Having a constant need to urinate
  • Flank discomfort or low back ache (which may indicate a kidney infection).

5. Treatment for Protein in Urine

Your healthcare professional can monitor trace quantities of protein in urine during pregnancy to see whether they pose a problem. Treatment for higher doses will depend on the underlying cause.

You will work with your doctor to choose the best course of action that is safe for both you and your unborn child when the causes of early pregnancy or first pregnancy may be related to underlying chronic health concerns.

Antibiotics are a safe way to treat infections like UTIs. Additional monitoring may be required for other issues. This can entail visiting experts other than your OB-GYN 4for professional medical advice.

There are several different techniques to treat and prevent preeclampsia. Your therapy will be determined by your stage of pregnancy, the severity of your ailment, and how you and the baby are doing. Although delivery is the most effective treatment for preeclampsia, if you are not far enough along, it might not be possible.

5.1) Other Treatments

i) Frequent observation.

To track changes in your child’s health or your child’s health, your doctor may want you to visit more frequently for tests.

ii) Drugs to lower blood pressure.

When blood pressure is exceptionally high, antihypertensives may be used to lower it. Options exist that are risk-free for pregnant women.

iii) Rest in bed.

Preeclampsia patients used to receive bed rest recommendations from doctors frequently. However, opinions on its effectiveness are divided. Due to an elevated risk of blood clots and other social and economic issues, bed rest is generally no longer advised.

Again, delivery can be the only option in cases of severe preeclampsia due to high blood pressure. Your doctor might administer a corticosteroid injection (or two, separated by 24 hours) if early delivery is required to assist mature your womb.

Your doctor might recommend corticosteroids if you have HELLP syndrome 5due to severe preeclampsia to help with platelet and liver function. This can help you continue to be pregnant longer so that your baby can grow, and if an early birth is required, it might even help your baby’s lungs grow.

You run a higher chance of developing complications, including placental abruption, severe bleeding, stroke, or seizures if you don’t get therapy for high blood pressure. Preeclampsia can sometimes be fatal. Therefore, if you exhibit any of the symptoms or if there are any risk factors, it’s crucial to communicate frequently with your healthcare provider otherwise, it may pose serious risks or serious complications.

6. Gestational Hypertension

Gestational hypertension6 is defined as a persistent increase in blood pressure to 140/90 mm Hg or more at least two times, 4 hours or more apart, after the 20th week of pregnancy or within the first 48 hours after birth in a woman who was previously normotensive.

It should meet the following requirements:

(1) No evidence exists for the primary cause of hypertension

(2) Typically unrelated to other developing preeclampsia symptoms (edema or elevated protein levels in urine).

(3) Most pregnancies last longer than or equal to 37 weeks.

(4) Typically not linked to hepatic impairment, elevated serum uric acid levels, hemoconcentration, or thrombocytopenia.

(5) The blood pressure should return to normal within a year of delivery. That is, there should be no noticeable symptoms of postpartum preeclampsia.

7. Chronic Hypertension in Pregnancy

The presence of hypertension from any source before the 20th week of pregnancy and for more than 12 weeks after birth is referred to as chronic hypertensive disease (CHD). The illness presents a challenging dilemma when diagnosed and treated for the first time after the 20th week of pregnancy. There is a 2-4% overall incidence, of which 90% are caused by essential hypertension.

Age (> 40 years), duration of hypertension (> 15 years), level of blood pressure (> 160/110 mm Hg), presence of any medical condition (renovascular), and presence of thrombophilias are the high-risk factors for CHD. Most CHD patients are at low risk and have positive maternal and fetal outcomes without using antihypertensive medication.

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Photo by CDC on Unsplash/Copyright 2021

8. Preeclampsia

Preeclampsia is a multisystem condition with an unknown aetiology that manifests as protein in urine during pregnancy after the 20th week in a woman who had previously had normotensive and nonproteinuric blood pressure. Oedema in some form is typical throughout a healthy pregnancy. The diagnostic criteria do not include oedema unless it is pathological.

8.1) Assessment Methods for Preeclampsia

i) Hypertension:

Pregnancy-induced hypertension is defined as an absolute increase in blood pressure of at least 140/90 mm Hg, an increase in systolic pressure of at least 30 mm Hg, or an increase in diastolic pressure of at least 15 mm Hg over the previously known blood pressure if the prior blood pressure is unknown.

At least two times with elevated blood pressure should be noticeable, at least six hours apart.

ii) Oedema:

The early sign of preeclampsia may be pitting oedema over the ankles after 12 hours of bed rest or a rapid weight increase of more than 1 pound per week or more than 5 pounds per month in the later stages of pregnancy.

iii) Proteinuria:

In the absence of a urinary tract infection, the presence of total protein in 24 hours’ worth of more than 0.3 grams or more than or equal to 2+ (1.0 g/L) on at least two random clean-catch urine samples tested more than or equal to 4 hours apart is considered significant.

8.2) Preeclampsia Risk Factors

The following are the risk factors for preeclampsia:

  • Primigravida: either young or old
  • Family history:Preeclampsia and elevated blood pressure
  • Anomalies of the placenta: Hyperplacentosis, Ischemic placenta.
  • Obesity: BMI greater than 35 kg/m2, insulin resistance
  • A history of vascular illness
  • New paternity
  • Thrombophilias [antiphospholipid syndrome, protein C, S, and Factor V Leiden deficiencies]

8.3) Preeclampsia Etiopathological Factors

  • Trophoblast invasion failure (abnormal placentation)
  • Injury to the vascular endothelium
  • Inflammatory mediators (cytokines)
  • Intolerance of foetal and maternal tissues to each other’s immune systems
  • Anomalies in coagulation
  • More oxygen-derived free radicals
  • Protein imbalance between angiogenic and antiangiogenic
  • Genetic predisposition (polygenic disorder)
  • Dietary excess or deficiency

8.4) Preeclampsia Symptoms

  • Persistent headache
  • Upper right abdominal pain
  • Vision alterations such as blurry vision, changes in eyesight, and the ability to see spots.
  • Face and hand swelling
  • Nausea or diarrhoea
  • Unexpected sudden weight gain
  • Difficulty breathing

8.5) Preeclampsia Clinical Findings

  • Oliguria
  • Visual and cerebral abnormalities
  • Respiratory oedema
  • Cyanosis
  • Impaired liver performance and elevated liver enzymes
  • Thrombocytopenia (low platelet count)
  • Birth weight underweight and restricted foetal growth

8.6) Investigations

i) Urine:

The final symptom of preeclampsia is proteinuria. It could be negligible or occasionally abundant enough that boiling urine will solidify (10–15 g/L). Hyaline casts, epithelial cells, and even red blood cells may be in short supply. Urine is collected for 24 hours to measure the protein.

ii) Ophthalmic Examination:

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Photo by Syed Hussaini on Unsplash/Copyright 2019

In extreme situations, there may be vein nicking where the arterioles cross them, constriction of the arterioles, modification of the usual vein-to-arteriole diameter ratio from 3: 2 to 3: 1, and retinal oedema. There could be bleeding.

iii) Blood Values:

The blood changes are vague and frequently erratic. Preeclampsia is present when the serum uric acid level (a biochemical indication of preeclampsia) is greater than 4.5 mg/dL.

The level of blood urea remains normal or slightly elevated. A serum creatinine level greater than 1 mg/dL is possible.

There could be variable degrees of thrombocytopenia and an irregular coagulation profile. The level of hepatic enzymes may rise.

iv) Antenatal Fetal Monitoring:

Frequent prenatal visits for physical examination, clinical examination, daily foetal kick count, ultrasonography for foetal growth and fluid pockets. For further testing cardiotocography, umbilical artery flow velocimetry, and biophysical profile can be used to check the foetal well-being during pregnancy.

8.7) Serious Complications Of Preeclampsia

i) Immediate

A) Maternal
During pregnancy:
  •  Eclampsia
  •  Accidental haemorrhage
  •  Oliguria and anuria
  •  Blurry vision and even blindness
  •  Preterm delivery
  •  HELLP syndrome
  •  Cerebral haemorrhage
  •  Acute respiratory distress syndrome (ARDS)

During labour:

  •  Eclampsia
  •  Postpartum haemorrhage


  •  Eclampsia
  •  Shock
  •  Sepsis
B) Foetal

ii) Remote

  • Residual hypertension
  • Recurrent preeclampsia
  • Chronic renal disease
  • Risk of placental abruption

8.8 Management of Preeclampsia

Most preeclampsia treatment is empirical and symptomatic as long as the aetiology is unknown. There is no specific therapy for proteinuria, which spontaneously decreases with the control of hypertension, despite efforts to reduce oedema and hypertension.

i) Hospital Management

  • Rest: Rest and hospitalization benefit the patient’s ongoing assessment and care.
  • Diet: The diet should include enough protein each day (about 100 g). Normal salt consumption is acceptable. Fluid intake need not be limited. A rough 1,600 calories are consumed daily.
  • Diuretics: Diuretics shouldn’t be used carelessly because they harm the unborn child by reducing placental perfusion and causing an electrolyte imbalance. Furosemide (Lasix) 40 mg, taken orally after breakfast for five days a week, is the most popularly used diuretic. The intravenous approach is favored in acute conditions.
  • Antihypertensives: The effectiveness of antihypertensive medications to reduce high blood pressure caused by preeclampsia is limited. The choice of drug is influenced by its local availability and usage history.
  • Pregnancy abortion is the only effective treatment for preeclampsia (delivery). As a result, the goal of the aforementioned treatment is to keep the pregnancy going as long as possible without harming the mother’s prognosis until the foetus is old enough to survive outside the womb (>37 weeks).
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Image by James Timothy Peters from Pixabay/Copyright 2015

ii) Methods of Delivery

iii) Management During Labour

During labour, blood pressure tends to increase, and stress chemicals may cause convulsions (intrapartum eclampsia). The patient ought to be lying down. If the blood pressure rises, antihypertensive medications are used. To identify impending eclampsia, it is important to constantly monitor blood pressure and urine output. When systolic BP > 160, diastolic > 110, and MAP > 125 mm Hg, prophylactic MgSO4 is initiated. The foetus’s condition needs to be carefully watched.

Low membrane rupture during the first stage of labour and the use of forceps or a ventouse during the second stage both shorten labour times. Following the delivery of the anterior shoulder, intravenous ergometrine is not administered since it could further raise blood pressure. However, administering syntocinon intramuscularly or slowly intravenously and keeping the patient under close monitoring for a while is not contraindicated.

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  1. Bartal, Michal Fishel, Marshall D. Lindheimer, and Baha M. Sibai. “Proteinuria during pregnancy: definition, pathophysiology, methodology, and clinical significance.” American journal of obstetrics and gynecology 226.2 (2022): S819-S834. ↩︎
  2. Chappell, Lucy C., Catherine A. Cluver, and Stephen Tong. “Pre-eclampsia.” The Lancet 398.10297 (2021): 341-354. ↩︎
  3. Mattoo, Tej K., Nader Shaikh, and Caleb P. Nelson. “Contemporary management of urinary tract infection in children.” Pediatrics 147.2 (2021). ↩︎
  4. Klebanoff, Jordan S., et al. “Ob/Gyn resident self-perceived preparedness for minimally invasive surgery.” BMC medical education 20.1 (2020): 1-8. ↩︎
  5. Petca, Aida, et al. “HELLP syndrome—holistic insight into pathophysiology.” Medicina 58.2 (2022): 326. ↩︎
  6. Antwi, Edward, et al. “Systematic review of prediction models for gestational hypertension and preeclampsia.” PLoS One 15.4 (2020): e0230955. ↩︎

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