What are the motifs in Wild Swans: Three Daughters of China by Edna St. Vincent Millay?

Self-sacrifice is a recurring idea in the story. Chinese women of only a few decades ago had little say over their lives and were often called on to sacrifice themselves in a loveless marriage for the sake of their families. While marriage wasn't the only place for that self-sacrifice, there's little doubt that many women—and even some men—married in order to make a better life for the family.