Women take on different roles in the book. First there is the Sweetheart of the Tra Bong who's real name was Mary Anne. She was the girlfriend of a soldier who shipped her over to be with him. Because of her exposure to the war, and the harsh reality of killing, she changes from a sweet, innocent blonde, to a killing machine, who wears human tongues as necklaces.
Other women, such as Martha, symbolize things left behind, dreams not realized, or unattainable goals.
The Things They Carried