Collecting period blood is straightforward with the right method. A menstrual cup is the most common and practical tool, but menstrual discs, specialty pads, and clinical sponges also work depending on why you’re collecting. The method you choose depends on whether you want to track your flow volume, preserve a sample for testing, or simply observe changes in color and consistency over your cycle.
Using a Menstrual Cup
A menstrual cup is the easiest way to collect period blood because it catches fluid directly and holds it in a measurable container. Most cups hold between 25 and 30 mL, and you can see graduated lines on many brands to track volume.
To insert one, wash your hands thoroughly, then fold the cup (the most popular folds are the C-fold, where you press the rim flat and fold it in half, or the punch-down fold, where you push one side of the rim down into the cup). Get into a comfortable position, either squatting or sitting on the toilet, and insert the folded cup into your vaginal canal. Once it’s in place, run a finger around the base to make sure it’s fully opened and created a seal. If you feel a slight suction, it’s seated correctly.
When you’re ready to remove it, insert your thumb and index finger until you can feel the base of the cup. Pinch the base to break the suction seal before pulling down slowly. Skipping the pinch creates uncomfortable resistance and increases the chance of spilling. Once removed, you can pour the contents into a clean container, measure the volume, or examine the fluid. Clinical research protocols for endometriosis studies use menstrual cups as their primary collection tool, with a single collection window of 5 to 8 hours during peak flow when the blood is bright red rather than brown.
Using a Menstrual Disc
A menstrual disc sits in a different spot than a cup. Instead of sitting lower in the vaginal canal, a disc rests in the vaginal fornix, the wider space just beneath the cervix, with the front rim tucked behind the pubic bone. To insert one, pinch the disc so it’s narrow, slide it in angled down toward your tailbone, then push the front rim up and behind your pubic bone.
Discs collect rather than absorb, similar to cups, so you can pour out the contents after removal. Because they leave the vaginal canal relatively unobstructed, they’re also an option if you want to collect blood over a longer wear period without interrupting daily activities. Removal involves hooking a finger under the front rim and pulling it out level to avoid spilling.
Using a Collection Pad
If internal collection isn’t comfortable or practical, specialty pads exist for this purpose. The Q-Pad Test System is an FDA-cleared menstrual pad with an embedded dried blood spot collection strip designed to capture a usable sample. You wear it like a normal pad, then peel out the collection strip and mail it to a lab. This is currently used for HbA1c testing (a diabetes marker), but the concept of pad-based collection is expanding.
In clinical research settings, a different approach uses a medical-grade sponge placed on top of a regular pad. The sponge absorbs menstrual fluid externally. Researchers estimate that about 40% saturation of the sponge yields roughly 3 to 3.5 mL, enough for biomarker analysis. This is a practical option if you’re participating in a study that provides collection materials.
Why Natural Sea Sponges Are Not Recommended
Natural sea sponges marketed as “menstrual sponges” have gained popularity, but the FDA has flagged serious concerns. Lab analysis of these sponges found particles of sand, grit, bacteria, yeast, and mold. One sample contained Staphylococcus aureus, the bacterium responsible for toxic shock syndrome. The CDC has documented at least one confirmed case of TSS linked to sea sponge use. If you want a soft, internal collection method, a medical-grade silicone cup or disc is far safer.
How Much Blood to Expect
The average total volume per cycle is about 87 mL, though the range is wide: anywhere from 15 to 271 mL across a full period. The midpoint for most people falls around 81 mL. If you’ve had previous pregnancies, your volume tends to run higher, averaging about 99 mL compared to roughly 46 mL for people who haven’t been pregnant. Anything over 169 mL per cycle is generally considered above normal for those who’ve given birth and may be worth discussing with a provider.
Collecting with a cup over several cycles gives you a reliable personal baseline. Since cups have volume markings, you can note how much you collect at each emptying and add it up over the full period. This is actually how researchers measure menstrual volume in clinical studies, as it’s more accurate than counting pads or tampons.
What Period Blood Can Reveal
Menstrual blood contains usable health information beyond what you can see with the naked eye. The FDA has approved testing menstrual blood for HbA1c, the standard marker for long-term blood sugar control in diabetes. Studies comparing HbA1c levels in menstrual blood versus blood drawn from a vein found no significant difference between the two, making your period a potential no-needle alternative for diabetes monitoring.
Research has also found that cholesterol, LDL, HDL, triglycerides, and a key inflammation marker (CRP) measured in menstrual blood closely match their values in standard blood samples. For endometriosis, two specific proteins are significantly elevated in menstrual blood compared to people without the condition, opening the door to non-invasive screening. These applications are still emerging for most uses, but the HbA1c testing via the Q-Pad system is available now.
Keeping Your Collection Clean
Between uses, a menstrual cup needs proper cleaning to prevent bacterial buildup. Most manufacturers recommend boiling for up to 10 minutes at the end of each cycle. Research on removing Staphylococcus aureus from silicone cups found that you don’t necessarily need a rolling boil the entire time. Rinsing with cold water and then steeping the cup in freshly boiled water for at least 5 minutes (poured into a mug and covered with a plate) was effective at eliminating bacteria. During your period, rinsing with cold water before reinserting is sufficient between empties.
If you’re collecting a sample for any kind of testing, use a clean glass or plastic container with a lid. Clinical protocols use sterile specimen cups, but any container that’s been washed with soap and hot water will work for personal tracking. Collect during peak flow when the blood is bright red for the most representative sample.
Storing a Sample
Fresh menstrual blood degrades faster than you might expect. For general health markers, blood stored at room temperature becomes unreliable after about 12 hours. Refrigeration at around 4°C extends that window: basic cell counts remain stable for about 24 hours, and some measures hold up to 3 days. Research protocols require menstrual samples to arrive at the lab within 60 hours of collection, kept refrigerated and never frozen.
If you’re collecting for personal observation (color, clot size, consistency), examine the sample as soon as possible after removal. Menstrual blood begins to oxidize and darken quickly once exposed to air, which changes its appearance within hours. For at-home tracking, taking a photo immediately after emptying your cup gives you a consistent record to compare cycle to cycle.