<unk> s are safe when used as directed and no health risks related to their use have been found. No medical research was conducted to ensure that<unk> s were safe prior to introduction on the market. Early research in 1962 evaluated 50 women using a bell-shaped<unk> . The researchers obtained vaginal smears, gram stains, and basic aerobic cultures of vaginal secretions. Vaginal speculum examination was performed, and pH was measured. No significant changes were noted. This report was the first containing extensive information on the safety and acceptability of a widely used<unk>  that included both preclinical and clinical testing and over 10 years of post-marketing surveillance. One case report noted the development of endometriosis and adenomyosis in one<unk>  user. Additionally, one survey with a small sample size indicated a possible link. Therefore, two organizations have issued a combined statement that urged further research. However, the U.S. Food and Drug Administration declined to remove<unk> s from the market, saying that there was insufficient evidence of risk. A 2011 randomized controlled trial measured urovaginal infection in a comparison of<unk>  and tampon use, and found no difference. No differences in the growth of Staphylococcus aureus or health harms were identified among school girls provided with<unk> s compared to those using<unk>  pads, or continuing their usual practice in rural western Kenya.<unk> s can be used with an IUD; however, there is an unclear association with respect to IUD expulsion. Toxic shock syndrome Toxic shock syndrome (TSS) is a potentially fatal bacterial illness. Scientists have recognized an association between TSS and tampon use, although the exact connection remains unclear. TSS caused by<unk>  use appears to be very rare. The probable reason for this is that<unk> s are not absorbent, do not irritate the vaginal mucosal tissue, and so do not change the vaginal flora in any measurable amount. Conversely, vaginal dryness and abrasions may occur if the tampon used is more absorbent than needed for the<unk>  flow, and normal liquid that should line the vaginal wall is also absorbed. Research has shown that the<unk>  has no impact on the vaginal flora, which means there is no effect on the presence of S. aureus, the bacterium that can cause TSS. The risk of TSS associated with cervical caps used for contraception in the female barrier method is also very low. Cervical caps and<unk> s both use mostly medical grade silicone or latex. A widely reported study showed that in vitro, bacteria associated with toxic shock syndrome (TSS) are capable of growing on<unk> s. A 2019 review found the risk of toxic shock syndrome with<unk>  use to be low, with five cases identified via their literature search. Data from the United States showed rates of TSS to be lower in women using<unk> s versus high-absorbency tampons. Infection risk is similar or less with<unk> s compared to pads or tampons.
Menstrual cup
Cloth menstrual pad
Menstrual pad
Menstrual cycle
Ovarian reserve
Vaginal ring
Sleep sex
Sex after pregnancy