Why is there smell in your menstrual blood?

Answer 1

Vaginal scent is a result of bacteria within the vagina.

The vagina is naturally acidic to maintain a healthy balance of 'good' and 'bad' bacteria - these bacteria help keep your vagina healthy and clean. Throughout your menstrual cycle hormonal changes effect your vaginal pH so effecting vaginal bacteria and in turn effecting vaginal scent. During menstruation as well as changes to your hormones the blood itself effects vaginal pH - also blood has a slightly metalic scent to it, and it's nutritious so creates a favourable environment for certain bacteria. Flora changes so scent changes.

What sanitary products you use makes a huge difference too.

Tampons keep menstrual flow within the body so it cannot be smelled during use, however after use tampons can cause bad odour because they give bacteria the perfect environment to multiply upon and by keeping blood in contact with the vagina they have a larger effect on vaginal pH. Commercial pads, for example Always or Kotex, can also cause more odour by preventing menstrual blood from drying, creating a warm moist environment for bacteria to thrive, and chemicals in these types of pads can themselves cause bad odour.

Answer 2

The smell in menstrual blood is due to the presence of bacteria and tissue that are shed from the uterus lining during menstruation. The blood can mix with vaginal fluids and bacteria, which can create a distinct odor. It's natural for menstrual blood to have a slight smell, but if it is very strong or foul, it may indicate an infection and you should consult a healthcare provider.