When you go to the doctor’s for your prenatal checkup, the nurse will weigh you, take a urine sample, check your blood pressure and your pulse, as well as ask you a series of questions. We understand that each of these procedures helps our care providers to understand the state of our health, and helps them to make decisions regarding our care. However, most women do not know how each of these procedures gives information to their doctors and midwives. I believe it is important to stay informed as consumers of health care, and urine analysis, as simple a procedure as it is, plays a significant role in the decisions we are expected to consent to. So here I will present the purpose of this particular procedure.
Surprisingly, your urine is a very good indicator of your health. As your body produces hormones, digests substances, and works to develop your baby, the urine excreted contains varying ingredients depending on what goes into your body and how your body uses the input. For instance, if you do not drink enough water and become dehydrated, your urine will become concentrated. It will appear darker, and smell stronger. On the opposite end, drinking an adequate amount of water will make your urine appear light and have very little smell.
In addition to the color and smell, presence of the following substances are tested for: sediment, protein, glucose, ketones, nitrites, blood, leukocytes, bilirubin, pH, and ascorbic acid. Care providers use each of these substances as indicators of the presence of dehydration, malnutrition, infection, and pregnancy conditions like gestational diabetes and preeclampsia. For the purpose of understanding how you can encourage health, and what questions to ask your care provider should an abnormal situation arise, I will now give you a basic description of each of the above substances and what each of them indicates.
Color. Light yellow urine indicates an adequate intake of water, whereas bright or amber tinted urine indicates too little water intake. If you are taking antibiotics or B vitamins, they can also cause your urine to become darker. A greenish tint to urine is common among those who are taking high doses of vitamins. This is not dangerous, instead it is the body’s way of excreting matter it doesn’t need. The last color you should be aware of is orange. Orange urine may be caused by urobilinogen, the indicator of anemia, jaundice and stress on the liver. Other colors – such as red, brown, or black – while rare, indicate severe problems. If you discover this in your urine at any time, please see your doctor.
Cloudiness/Sediment. Normally, urine should be clear. No matter the color, you should be able to see right through it. If you can’t, it may be because of vaginal mucus that washed into the sample. Other causes include the body eliminating excess nutrients, an alkaline pH level, or in the case of the presence of nitrites, it can also indicate infection of the bladder or kidneys.
Leukocytes. Leukocytes are white blood cells. These are the cells your body uses to fight infection. If your body is fighting any infection, whether from a cold, a yeast infection, or an ingrown toenail, leukocytes will die in the process. The dead are then excreted in the urine and therefore indicate than an infection is being fought. Most infections are marked by both leukocytes and nitrites, except yeast infections which are marked by leukocytes alone. You should know, however, that false positive readings of leukocytes are common in pregnancy, so infection should be confirmed by the testing of nitrites and a bacterial count.
pH. pH is a measure o the acidity or alkalinity of a solution. The measure is based on a scale of 1 (most acidic) to 14 (most alkaline). Normal urine has a measure of 6, and so is considered physiologically neutral. If your urine is acidic (lower than 6) it could be for a number of reasons: your diet is high in protein or cranberries, or you may have uncontrolled diabetes. Alkaline urine (higher than 6) can be caused by the following: recent intake of fruits, veggies and dairy products, a bacterial infection, carbohydrate starvation (also marked by ketones), and taking aspirin.
Protein. In the average person, no protein will be detectable in the urine. Occasionally, a trace can be seen for the following reasons: dehydration, mucus in the urine sample, a urinary tract infection, excessive exercise, hypertension, and standing for long periods of time. The condition that care providers are most concerned about when detecting protein in the urine is Toxemia (beginning with preeclampsia and then eclampsia). Toxemia indicates severe stress on the liver and kidneys due to a contracted blood volume. In most cases, this condition disappears within a week after delivery, but it can cause severe problems (and rarely, death) for both the mother and unborn child. Studies show that adjusting the diet to include more protein may decrease stress on the liver and kidneys. If protein is present in your urine, your care provider will discuss with you the other symptoms of Toxemia.
Glucose. As with protein, the ideal amount of glucose in the urine is none. If you have been eating sweets recently, this can cause a spike of glucose in your urine, but this is of virtually no concern. If, however, glucose continues to spill into your urine, your care provider will recommend a test for gestational diabetes, as glucose in the urine is the primary indicator of this condition. You can help to prevent and treat diabetes by cutting all sweets and simple carbohydrates from your diet as much as possible. If you are showing no other signs of diabetes (such as the presence of ketones in your urine), it may just be the natural reduction of the glucose threshold in pregnancy. In this case, taking nettle leaf infusions or capsules can help strengthen your kidneys.
Nitrites. When your urine is tested for nitrites, they are basically testing it for bacteria. Usually, bacteria is the cause of bladder and kidney infections. Therefore, the presence of nitrites is an indication to test for an infection. The most accurate test results come from first morning urine because nitrites need about four hours to incubate in the bladder before they will show up in a urine analysis. However, urine that has been sitting at room temperature for more than half an hour, urine taken from an “unclean” catch, high vitamin c intake, dehydration, drugs that turn urine red, and digestive disorders are all more likely to lead to a false reading of nitrites. It is important to test for nitrites because often it is the first sign of infection (accompanied by painful or frequent urination), which can eventually lead to severe kidney damage.
Ketones. Ketones are a substance that, if excreted in the urine, indicate that your body is burning fat. This could be for two reasons: One, you had a period of unusually intense exertion within the past 12 hours, or because you and your baby are not getting enough to eat. If this happens on a singular occasion, there is probably no reason to worry, but a repeated reading of ketones warns of an impending miscarriage because essentially your baby is getting hungry. To avoid this situation, do not overwork yourself to the point of excessive fatigue, and try not to skip any meals.
Blood. Even if you can’t see any blood, blood cells can appear in your urine. This can mean different thing, depending on whether it is coming from your vagina or urethra. A clean catch can help to determine its origin. Blood coming from the vagina at the end of pregnancy can indicate that your body is preparing for birth. Blood in the urine may indicate an infection (especially when in combination with nitrites and leukocytes), but results may read positive for the following reasons, though they may or may not be anything to concern yourself about: ingestion of aspirin, high doses of vitamin c, anemia, alkaline urine, heavy smoking, and hypertension. By itself, the presence of blood in the urine analysis is probably nothing to be concerned about, but it can help to confirm other findings.
Bilirubin. Bilirubin is not normally seen in the urine. It is excreted by the liver and only appears when the liver or gallbladder are compromised. If found in the urine, your care provider should recommend further blood tests to ensure that your liver and gallbladder are functioning normally. You should be aware, however, that this particular substance can be difficult to read, so if it comes back positive, do not be concerned until you are given more reason to be. Reasons why the test may be falsely negative include high doses of vitamin c, the presence of nitrites in the sample, exposure to the light or if it is left standing at room temperature for too long. False postive readings may be read if you also have diagnostic dyes or certain drug metabolites in your urine.
Ascorbic acid (vitamin c). Because high doses of vitamin c can interfere with so many of the substances being tested for in the urine analysis, some care providers also test for the presence of vitamin c. If it is detected, it may be advisable to repeat the urine test 10 or more hours after the last vitamin c intake (either nutritional or supplemental), in order to get a more accurate reading of the other substances.
You may be wondering how knowing this information really helps you at all. The reason is that although your care provider has a better understanding of the science behind urine analysis, you have a better understanding about the history of your body. Now that you know what causes the results, you’ll know what to ask if something comes back abnormal. Don’t be afraid to ask questions of your care provider, or to offer information about your lifestyle that may have affected the results. You will receive the best care possible if the two of you work together to get the information you need to make good decisions for you and your baby.
Sources:
“Understanding Diagnostic Tests in the Childbearing Year” 6th edition, by Anne Frye
Spirit-Led Childbirth handout www.babybirthandbeyond.com
http://www.webmd.com/a-to-z-guides/urine-test?page=4
