Menstrual cycle shortest and longest cycle lengths is considered very irregular. The average menstrual cycle lasts 28 days. The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 25 to 39. Subsequently, the variability increases slightly for women aged 40 to 44. The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14.13 days, standard deviation 1.41 days) whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).
Menstrual cup capable of growing on menstrual cups. However, there have only been two confirmed cases of toxic shock syndrome (TSS) associated with the use of the menstrual cups. The first case was a woman who had a history of Hashimoto’s thyroiditis and chronic menorrhagia. In the second case, the menstrual cup had been left in for 7 days. Menstrual cups are generally bell-shaped, with a few exceptions. Most brands use medical grade silicone as the material for the menstrual cup, although latex and thermoplastic elastomer are also options. Menstrual cups made from silicone are generally designed to last for 1–5 years.