Toxic shock syndrome (TSS) is a very serious condition that occurs when bacteria, usually staphylococci (but sometimes streptococci or other bacteria), produces a toxin that enters the blood stream. It can cause fever, low blood pressure, muscle pains, rash, and organ failure. One source of the bacteria is from the vagina during menstruation, the theory being the blood and other environmental changes during menstruation provide a good medium for growth of the bacteria and production of the toxin. Another theory is that the micro trauma associated with tampon insertion and removal makes it easier for the bacteria and toxin to enter the blood stream from the vagina. The bacteria and toxin can also be produced in the vagina after delivery or after gynecologic surgery or can come from a non-gynecologic site (such as a skin infection). The incidence of TSS is 0.5/100,000 overall and 1/100,000 among women ages 15-44. The highest risk is among women ages 15-24 (approximately 1.5/100,000). The risk of death from menstruation related TSS is 1.8% and 6% for non-menstrual TSS. Non-menstrual TSS is becoming more common.
A clustering of cases associated with menstruation in the 1970’s prompted TSS to be classified as a reportable disease. Initial studies identified an association between tampons and mentrual-TSS, specifically Rely tampons. Rely was unique in that it contained carboxymethycellose which, coupled with the unique cup like design, made it REALLY absorbent. Several studies have looked at tampon risk factors and some found no association between tampon absorbency or the frequency of tampon change and some fond an increased risk of TSS with increasing absorbency. Rely was pulled from the market and the chemical composition of tampons was changed (they are now far less absorbent). Tampons are now made from cotton or cotton and rayon. Some lab studies suggest that the toxin is less likely to grow with a cotton tampon, but other studies refute this. There is no data that shows a link between rayon tampons and TSS.
What we do know is that the number of cases of TSS associated with menstruation have dropped dramatically. Whether this is due to the change in tampon absorbency, change in chemicals, increased awareness of TSS due to changes in product labeling, or another factor (such as a change in the way staphlyococci and other bacteria produce toxins) isn’t know. A large observational study (more than 5,000 cases of TSS identified over 17 years) reported that 89% of women with menstrual TSS used tampons exclusively. Tampon absorbency was available for 41% of women with menstrual-TSS and 28% used regular tampons and 71% used super-absorbency. However, we have no idea how this tampon use pattern compared to controls. For example, in my peer group everyone uses tampons exclusively and they only use super-absorbent. Without an age-matched control group for comparison the data on tampon absorbency means very little.
As far as tampons increasing the risk of TSS because of micro trauma with insertion or removal, other conditions that can cause small breaks in the vagina, such as herpes lesions and skin conditions or having a pessary, don’t seem to be associated with TSS. No link has been identified between menstrual cups (which can be worn for up to 12 hours) and TSS, although menstrual cups are far less common in the US so given the rarity of TSS, it’s not possible to say too much.
So what’s the verdict? While menstrual-related TSS is a known entity and a serious illness, it is very uncommon. The data that linked tampon absorbency with TSS was with tampons that were far more absorbent and manufactured with chemicals not currently in use. There is also no data to say how long is “too long” between tampon changes. We know that forgetting a tampon in the vagina can cause an overgrowth of bacteria, but the exact timing of the transition from good bacteria to potentially dangerous bacteria isn’t know.
Many factors are probably involved in developing TSS. For example, studies now tell us that most women (85%) have protective antibodies against the most common toxin that causes menstrual-TSS and therefore are not at risk for the disease. Interestingly, 98% of women who carry the toxin-producing bacteria (either in their nose, vagina or anus) have antibodies and are therefore immune to the toxin.
The recommendation to avoid using modern tampons overnight and to use the lowest absorbency tampon certainly errs on the side of safety (not necessarily a bad thing) and reduces manufacturer liability, but does not seem to get a thumbs-up or a thumbs-down from the medical literature. An association between modern tampons and menstrual TSS is only suggested by one study that has no control group and no one has proven exactly how tampons are associated with TSS. Given how uncommon TSS is, it is hard to see how there will ever be enough data to say with any scientific certainty that super or regular tampons are safer than super-plus or that tampons should be alternated with pads. However, more studies that look at the immune system may be able to clarify who is not at risk.
*Remember this post does not represent individual medical advice