Is it safe? · Pregnancy Smart

How do I collect 24-hour urine during pregnancy?

Assigned clinical reviewerPerry Friedman· MD, FACOG-MFMDraft · pending clinical reviewUpdated September 18, 2026

Evidence summary: consult your healthcare provider

A plain read of what the published evidence shows. The decision belongs with you and your clinician.

The short answer · How do I collect 24-hour urine during pregnancy?

A 24-hour urine collection measures what your body releases in urine over a full day, often to assess protein during pregnancy. Use the laboratory's container and instructions, record the exact start and finish times, and collect every required sample. Report a missed collection rather than guessing; urgent symptoms should never wait for the test to finish.

This is a working draft: sourced from published clinical guidance and awaiting sign-off from its assigned clinician. It isn't personal medical advice, so consult your healthcare provider before changing anything in pregnancy.

What does the evidence say about 24-hour urine collection in pregnancy?

A common collection method begins by emptying your bladder into the toilet and recording that time. Collect subsequent urine for the next 24 hours, including the final sample at the matching time the next day. Follow the laboratory's instructions for storage, labeling, and return. 1
Urine protein can vary through the day, which is why a timed collection may be useful. It is different from giving one small sample at an office visit. Before starting, ask how much container space you need and what to do if the supplied container fills. 2
Urine testing can be part of assessment for preeclampsia, together with blood pressure and blood tests. The order itself does not establish that you have the condition. Ask whether the clinician is investigating a new concern or obtaining information for comparison later. 3
The result needs its units, the collection details, and the clinical picture. A number expressed per day is not interchangeable with the concentration in one cup of urine. Have the ordering team interpret the report and tell you whether the collection was adequate. 4
Severe headache, vision changes, chest pain, trouble breathing, or severe persistent abdominal pain need prompt medical attention. Do not finish the collection first or wait for a result before calling. Tell the maternity team that a timed urine test is underway. 5

How does urine testing fit into pregnancy follow-up?

First trimester. A baseline collection may be requested for a specific medical reason; confirm what it will establish.
Second trimester. If symptoms or blood pressure lead to testing, clarify how quickly the team expects the result.
Third trimester. Plan storage and transport while keeping the maternity contact number readily available.

Questions to bring to your prenatal team

Item to clarify	Why it matters
Start and finish	Write down exact times using the laboratory protocol.
Missed sample	Call for instructions rather than estimating.
Storage	Confirm temperature, container handling, and transport.
Symptoms	Seek urgent assessment independently of the collection schedule.

Frequently asked questions

Do I save the first urine when I start?

In the usual method, you discard the first void and write down the time, then save every required void afterward. Follow your laboratory's written directions if its process differs.

When does the final sample belong in the container?

The usual collection includes urine passed at the end of the full 24-hour period. Record the completion time accurately and use the laboratory's labeling and return instructions.

What if I accidentally miss one sample?

Contact the laboratory or ordering team and explain what happened. An incomplete collection may not answer the intended question. Do not invent an amount or extend the collection on your own.

Should I keep the container cold?

The standard instructions call for a refrigerator or cool storage, but use the directions supplied with your container. Ask how to store and transport it safely before starting.

Should I drink much more water to improve the result?

Do not deliberately change fluid intake to influence the result. Ask whether any preparation is needed and describe unusual thirst, vomiting, or difficulty maintaining fluids to your prenatal team.

Should I stop medicines or supplements for the collection?

Tell the team everything you take. Some products can affect testing, but you should change a prescribed medicine only when the clinician gives specific instructions.

Can a single urine sample be used instead?

Sometimes a protein-to-creatinine ratio from one sample can answer the clinical question. Ask whether it is appropriate in your situation; do not substitute it for the ordered collection yourself.

Does a reassuring protein result rule out every blood-pressure concern?

No single test supplies the whole assessment. Continue the blood-pressure and symptom plan your clinician recommends, including urgent contact for concerning symptoms even while results are pending.

References

24-hour urine protein
MedlinePlus · https://medlineplus.gov/ency/article/003622.htm
Protein in Urine
MedlinePlus · https://medlineplus.gov/lab-tests/protein-in-urine/
Preeclampsia and High Blood Pressure During Pregnancy
ACOG · https://www.acog.org/womens-health/faqs/preeclampsia-and-high-blood-pressure-during-pregnancy
How to Understand Your Lab Results
MedlinePlus · https://medlineplus.gov/lab-tests/how-to-understand-your-lab-results/
Urgent Maternal Warning Signs and Symptoms
CDC · https://www.cdc.gov/hearher/maternal-warning-signs/index.html

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.