Why Do I Experience a Distinct Odor During My Period? Find Out Why

Period odor is normal because blood mixes with bacteria and air. Change products regularly and see a doctor for a strong or unusual odor.

Why

Blood and tissue mixed with normal vaginal bacteria cause a mild, metallic odor. Air adds to it.

Normal

A mild odor is normal.

Reduce

• Change pads and tampons every 4 to 8 hours.
• Wash with water.
• Wear breathable underwear.
• Menstrual cups or period underwear may help.

Not normal

A strong fishy or foul smell with itching or discharge can be an infection like BV.

See a doctor

If it persists.

Reasons odor varies

Menstrual blood has a mild metallic scent from iron. After exposure to air and bacteria, the smell can become stronger, especially in warm conditions or with pads that hold moisture. The vaginal microbiome is dominated by Lactobacillus, keeping pH at about 3.8 to 4.5, and period blood raises pH to around 7.4, which can shift bacteria and change odor.

• Changing pads or tampons every 4 to 8 hours reduces odor. Tampons should not stay in longer than 8 hours because of toxic shock syndrome risk.
• Scented pads, sprays and douching can irritate tissue and disturb the microbiome.
• Cotton underwear and showering daily with water or mild unscented soap on the outer area are enough.

When odor signals a problem

A strong fishy smell with gray discharge points to bacterial vaginosis, the most common vaginal condition in women aged 15 to 44. A foul smell with fever or pain may be infection, or a forgotten tampon. Trichomoniasis causes frothy yellow-green discharge. These conditions are treated with antibiotics such as metronidazole, so a clinic visit is needed for diagnosis.

Why odor varies

Menstrual blood mixes with vaginal bacteria and has a mild metallic odor that is normal. Odor can increase when blood sits in a pad. Change products every 4 to 8 hours and tampons no longer than 8 hours to reduce toxic shock syndrome risk.

When it signals a problem

A strong fishy or foul smell may signal bacterial vaginosis, trichomoniasis or a forgotten tampon. Seek care for itching, unusual discharge, fever or pain. Avoid douching and scented products.

Hygiene practices

Menstrual flow is about 30 to 80 mL per cycle, and blood exposed to air oxidizes and mixes with bacteria. Change pads every 4 to 6 hours, tampons every 4 to 8 hours and empty menstrual cups every 8 to 12 hours. Wear breathable cotton underwear and wash the vulva with water or mild unscented soap. Avoid douches and scented products.

Infections to watch

Bacterial vaginosis affects about 29 percent of US women, with a thin gray discharge and fishy odor, treated with metronidazole or clindamycin. Trichomoniasis causes frothy yellow green discharge. Toxic shock syndrome is rare but serious, with fever, rash and low blood pressure, and needs emergency care. A forgotten tampon causes foul odor within days.

Based on data from the CDC and the American College of Obstetricians and Gynecologists