How did Pink become a colour for women?

In the year 1918, pink was just a colour, not a 'gender defining colour'. Men or women all used to wear pink equally. In fact, even if pink was labeled to some extent, it was called the color of males only. Because at that time the army soldiers of many countries used to have red uniform, and since pink is considered to be a lighter shade of red colour, then boys were made to wear pink more in their childhood. It was mentioned in the article Pink or Blue of the 1918 journal The Infants' Department. But then what happened that pink became the color of women.