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.
It is useful to keep two general distinctions in mind (for more detailed definitions consult Abrams 1999 and Preminger et al 1993): lyric poetry and narrative poetry. Lyric Poetry. A lyric poem is a comparatively short, non-narrative poem in which a single speaker presents a state of mind or an emotional state. Lyric poetry retains some of the elements of song which is said to be its origin: For Greek writers the lyric was a song accompanied by the lyre.