1. Menstrual Blood gets contaminated with the body’s innate organisms once it has left the body. Since your pad is still damp and will have organisms from your vagina, sweat from your genitals, etc. When these organisms remain in a warm and moist place for a long time they tend to multiply and can lead to conditions like urinary tract infection, vaginal infections and skin rashes.
2. Women are slightly more vulnerable to bacterial infection during menstruation, due to the change in the vagina’s pH balance
pH is a measure of the acidity of the vaginal environment. In healthy women, vaginal pH is typically 3.5 to 4.5. This pH is ideal for beneficial bacteria and creates a hostile environment for pathogenic bacteria that cause odor and infection. A healthy pH both helps beneficial bacteria to thrive and prevents overgrowth of yeast and pathogenic bacteria.
Blood has a pH of 7.4, so during your period your vaginal pH becomes elevated by menstrual fluids. Tampons can contribute to an elevated pH as they retain the fluids that cause pH to increase. The changing pH is part of the reason why many women who suffer from recurrent infections find that their period is often the event that sets them in motion
It is also important that the tampon is changed every 4 to 6 hours to reduce the risk of Toxic Shock Syndrome.
When pH becomes elevated, the vaginal environment shifts in favor of the pathogenic bacteria. This can allow unwanted bacteria to cause odor, irritation and possibly infection. Elevated pH is one of the key factors doctors look for when diagnosing vaginal infections. Maintaining vaginal pH within the healthy range can help reduce risk of infections.