During that pregnancy, the mother's antibodies cross the placenta to fight the Rh positive cells in the baby's body. As the antibodies destroy the red blood cells, the baby can become sick. This is called erythroblastosis fetalis during pregnancy.
Sometimes, however, as in a lyric poem, the effect intended may be the rendering or creation of a mood, such as that of happy content, and in that case the poem may not have an easily expressible concrete theme. Lyric poems are expressions of spontaneous emotion and are necessarily short.
Dramatic poetry is a form of writing that expresses emotional feelings. It's a very creative form of art. Poetry that simply expresses emotions is actually lyric poetry. Dramatic poetry involves a narrative poem of a person in a specific situation. It can involve emotions, but has so much more to it.