Menstrual tampons are feminine hygiene devices, usually made of absorbent cotton, that are temporarily inserted into the vagina for absorbing a woman’s blood during menstruation. In 1931, Earl Haas invented the menstrual tampon most commonly used in the twenty-first century. Later, Gertrude Tendrich produced the first commercial tampon brand, Tampax, using Haas’s patented design. Tendrich and Haas’s tampon was made of tightly compacted absorbent cotton, shaped like a bullet, and had a string attached at the base that allowed for easy removal from the woman’s body. Some tampons had a plastic or cardboard applicator, while other digital tampons could be inserted with a finger. The invention of the tampon expanded women’s options for efficient menstrual flow management solutions and allowed women to be more physically active while menstruating.

The figure depicts three different molecular structures of estrogen found in mammals’ that differ by the arrangement of bonds and side groups. The molecular structures of the three estrogen molecules differ by the arrangement of chemical bonds and side groups attached to the core steroid structure, cholesterol, which contains three cyclohexane rings and one cyclopentane ring.

Menopause is defined as the point in time exactly twelve months after a female has had her last menstrual period, or shedding of the lining of the uterus. As a female ages, the hormone levels that drive menstruation decrease, beginning the process of perimenopause, which eventually leads to menopause and can result in various symptoms including depression, difficulty sleeping, and hot flashes, or abrupt feelings of heat typically in the upper body. Once a female reaches menopause, those symptoms typically subside, but after menopause, the risk of other health conditions such as osteoporosis, or brittle bones, increases. At least since the fourth century BCE, researchers understood that menopause occurred in females but held many negative ideas and misconceptions about the process, which resulted in stigma that left females uninformed about what happened to their bodies as they aged. Research on and perceptions towards menopause evolved over the twentieth century, and as of 2024, researchers understand it as a typical part of aging and development in females, marking the end of their reproductive years.