Some people might notice different types of smells to their period blood, such as a metallic or sweaty smell. A rotten or fishy odor may be a sign of an infection or foreign body such as a tampon.

Several factors can influence the smell of menstrual blood, such as the vagina’s pH and the presence of bacteria.

This article will discuss different types of period blood smell and when to contact a doctor.

Menstruation involves the shedding of blood and tissue from the uterine lining through the vagina. It occurs when the egg released during ovulation is not fertilized to result in pregnancy.

The menstrual fluid, consisting of blood, the unfertilized egg, and uterine lining tissue, might have a slight smell to it.

A person might notice that their period blood smells metallic due to the presence of blood and iron.

The vagina’s acidic environment and the presence of different types of healthful bacteria may also contribute to the smell of vaginal secretions and period blood.

The typical pH of the vagina is 3.8 to 5, which is acidic. A pH of 7 is neutral. The presence of blood, semen, or urine in the vagina can affect the pH and cause different odors.

The vagina is home to different types of healthful bacteria, including Lactobacillus. A disruption in this environment can cause infections and other problems.

Period blood can have different odors based on numerous factors. The following are common menstrual blood odors:

Metallic

Period blood can have a metallic smell, like a copper coin. This is typically due to the presence of iron in the blood.

Rotten

A person might notice a bad or rotten smell during their period, which could be a sign of a problem.

This type of smell is often due to a foreign body, such as a tampon, that a person has accidentally left in the vagina for too long.

A person can try to remove an old tampon from the vagina by finding the string and pulling it out. Otherwise, a doctor will need to remove it.

Sweet

A sweet smell in the period blood is likely due to the acidic environment and the presence of bacteria in the vagina.

Body odor

A person might notice a smell that is similar to body odor during their period. This is due to the presence of apocrine sweat glands in the genital region.

Apocrine sweat mixes with bacteria on the skin to produce body odor. The glands release this type of sweat during periods of stress.

It is different from the sweat lost during exercise, or when the body has a high temperature.

Fishy

A person might notice a fishy smell during their period and also outside of menstruation. This smell is often related to an infection, such as bacterial vaginosis or trichomoniasis.

Bacterial vaginosis is a common vaginal infection caused by an overgrowth of bacteria in the vagina. Risk factors for bacterial vaginosis include new or multiple sex partners and douching.

Bacterial vaginosis produces a fishy smell, which is more pronounced during menstruation, as blood increases the vaginal alkalinity.

A person might have white or gray vaginal discharge outside of menstruation.

Doctors diagnose bacterial vaginosis using a range of tests, and typically prescribe antibiotics for treatment.

Another infection that produces a fishy smell during a person’s period is trichomoniasis, which is a common sexually transmitted infection. It can pass from one person to another through sex.

A person with trichomoniasis might notice an unusual fishy smell from the vagina and a change in vaginal discharge. They might also notice itching, burning, or soreness in the genital area.

Doctors diagnose trichomoniasis with laboratory testing and treat it with antibiotics.

A person should aim to bathe daily to reduce unwanted odors. Additionally, during menstruation, they should change a pad or tampon regularly. For heavy periods, they may need to change a tampon every 1 to 2 hours.

It is important to never wear the same tampon fo rmore than 8 hours.

There is no need to use special cleansers or sprays to clean the vagina. If a person chooses to use feminine hygiene deodorants or other products, they should proceed with caution as these products can irritate the vaginal area.

Doctors do not recommend the use of a douche to clean the vagina. Douching can change the balance of bacteria and levels of acidity in the vagina. It can also cause a buildup of harmful bacteria and lead to infections, such as bacterial vaginosis or yeast infections.

People do not have a period during pregnancy, but should still be aware of vaginal health.

If a person has bacterial vaginosis or trichomoniasis during pregnancy, they have a higher chance of delivering their baby prematurely or having a baby with low birth weight.

Due to hormonal changes, a person might have more regular vaginal discharge during pregnancy than they usually do. They are also at risk for vaginal infections due to the changing balance of yeast and bacteria in the vagina.

Anyone who experiences unusual changes in vaginal discharge, strange odors, or vaginal bleeding during pregnancy should speak to a doctor.

It is best to contact a doctor if a person notices a change in smell during their period or in their vaginal discharge in between periods.

People should also speak to a doctor if they experience the following during their period:

  • a fever
  • severe pelvic or stomach pain
  • bleeding heavier than usual

A doctor can help identify whether there is an infection or other condition that requires medical treatment.

The vagina is an acidic environment with a balance of bacteria that produce odor. Some common smells include a metallic or sweet smell.

Some smells, such as a fishy or rotten smell, could indicate an infection. A person experiencing them should see a doctor for further investigation. People should also pay attention to changes in vaginal discharge outside of their period.