How does Doris Lessing use imagery in The Fifth Child?

David and Harriet are portrayed with what seems like a minimum of words and images. The author supplies just enough imagery get across what is really important - Harriet's pregnancy with Ben, and everything that happens to her after that. Once Ben appears on the scene, even in utero, the amount of detail the narrative employs to portray his presence and his effect on Harriet and the family increases substantially. Here again, there is the sense that style manifests substance - the narrative's use of language reflects what's going on in the plot ... the most important element of the characters' lives gets the most attention.