Three of pregnancy's more common complications are gestational diabetes, preeclampsia and urinary tract infections — all of which have markers that show up in your urine. That's why at every prenatal visit, you'll have to give your doctor a urine sample.

What urine tests detect during pregnancy

In most practices, a quick urinalysis during each prenatal checkup gives your practitioner a heads-up if you potentially have a condition that requires treatment. Urine tests during pregnancy look for the following:[1]

  • Diabetes. High levels of glucose (or sugar) in your urine may indicate pre-existing type 1 or type 2 diabetes or, later on in pregnancy, gestational diabetes (GD). Gestational diabetes is also tested for with a glucose (blood sugar) screening between weeks 24 and 28 of pregnancy.
  • Preeclampsia. Protein in your urine is sometimes a sign of preeclampsia, or pregnancy-induced high blood pressure.
  • A urinary tract infection (UTI). If you have symptoms of a UTI, your practitioner will look for red or white blood cells in your urine.
  • Dehydration. Dark, tea-colored urine usually signals that you need to drink more water. Two common causes for preterm contractions include dehydration and UTIs, but luckily practitioners can treat both easily (and dehydration can be avoided by drinking plenty of fluids throughout the day).

How prenatal urine tests are done

You provide the sample, so strategically up your water intake before each visit. For the most accurate results, practitioners recommend that you:

  • Wash your hands and wipe the labia clean from front to back (usually with a wipe provided by the doctor).
  • Start peeing in the toilet.
  • Catch the urine midstream with the collection cup.
  • Continue filling to the mark indicated by your practitioner (usually about 1 to 2 ounces).

A nurse or technician will insert a dipstick into the sample or place a few drops of urine onto testing strips to check for sugar, protein or blood cells. A color change indicates a positive test. 

Urine is also sometimes analyzed under a microscope to check for red and white blood cells.

What it means if you have glucose in your urine

Try not to stress: Many women test positive for glucose at some point during pregnancy. (For example, it’s common to have glucose in your urine on the day you drink your glucose drink or after eating a very high-sugar food.) The body will continue to adjust your insulin levels over time, so that most people will not develop gestational diabetes. 

If you continue to have glucose in your urine and blood tests as your pregnancy progresses, you may have gestational diabetes. The condition can be confirmed with a glucose tolerance screening and test. 

Your practitioner will likely do a glucose screening test much earlier in your pregnancy, maybe even at your first prenatal visit, if you have risk factors for gestational diabetes. Those include being overweight, having a condition like PCOS, having a history of diabetes in your family, or experiencing gestational diabetes in a previous pregnancy.[2]

What it means if you have protein in your urine during pregnancy

Protein in the urine sometimes means you could have preeclampsia (though not always, so talk to your practitioner). You may have preeclampsia if you have high blood pressure along with one or more other symptoms of the condition after week 20 of pregnancy.

To diagnose preeclampsia, your doctor may ask you to collect your urine for 24 hours. The combination of elevated protein in your urine and hypertension can be used to diagnose preeclampsia.

Your practitioner may also measure other markers, like your liver enzyme levels and blood platelet count, to make a diagnosis.  

If it turns out that you do have preeclampsia, your doctor will make specific recommendations for the management of the condition. See your practitioner regularly so you and your baby get the care you need.[3]

What it means if you have a UTI during pregnancy

UTIs are more common during pregnancy thanks in part to an increase in muscle-relaxing pregnancy hormones that allow more bacteria to enter your urethra. An overgrowth of bacteria in the urethra or bladder is known as a UTI. If the bacteria makes it into your kidneys, it may lead to a kidney infection.[4]

A urine test at your doctor’s office checks for red and white blood cells (also known as leukocytes). Having red blood cells and leukocytes in your urine may indicate that you have a urinary tract infection, but white and red cells are not diagnostic, and usually your doctor will want to send your urine for a urine culture to see if bacteria grow out of your urine in a lab and to guide treatment.

A UTI in your urethra or bladder can be easily taken care of with a course of pregnancy-safe antibiotics prescribed by your doctor. A kidney infection may require a round of IV antibiotics at the hospital.

It is very important to treat a urinary tract infection in pregnancy because the risk of kidney infections is higher, and because kidney infections put you at risk for preterm labor.

Risks of urine tests during pregnancy

There are no risks associated with prenatal urine tests to you or your baby. Although the mechanics of peeing into a plastic cup get pretty interesting in your ninth month (!) just try to “go with the flow.”