Because of its connection with mother Goddesses, the spiral is a very feminine symbol, representing not only women but also a variety of things traditionally associated with women.
Besides life cycles, fertility and childbirth, the spiral can reference intuition and other more internal concepts associated with women.
Spirals in Nature
Spirals and circles are much more commonly found in nature than straight-edged shapes like triangles and squares. As such, people today tend to associate spirals with the natural world as opposed to the constructed, mechanical and urban world. Spirals are primal, raw, and unrestrained by man.
Moreover, ancient people were acutely aware of cyclical forces of nature: monthly lunar patterns, yearly solar and seasonal patterns, which in turn affect yearly patterns in plant growth and animal husbandry.
It has been suggested that at least some of the ancient spirals represent the sun, so it is sometimes described as a solar symbol. However, solar symbols are strongly male-oriented, so its use in modern beliefs is limited.
Spiral of the Cosmos
Even ancient people could recognize that the stars overhead spun around a central point every night, and today we know we reside within a spiral galaxy. Thus, the spiral can be a symbol of the universe and our place within it and of the great cycles that constantly advance within this universe.