Cover shown is the 1982 first edition paperback from Signet Books (USA).
Before commencing her two successful mystery fiction series (Betty Trenka and Lady Margaret Priam), Joyce Christmas wrote three horror novels, all of which are currently out of print. And after reading Blood Child, I can see why she wouldn't want them to be unearthed: this is trashy fiction at its worst.
The novel opens with young Hattie Bell deep in a nightmare, dreaming of the baby and husband she lost a few years before. She's currently pregnant, the anonymous surrogate mother for a childless couple. Her hope is that the birth of the baby will end the nightmares. After her son is born it is transferred to another hospital and Hattie goes home alone - to find that the nightmares have not stopped.
Flashbacks reveal that Hattie skillfully choreographed an affair with a renowned obstetrician, and used blackmail to then force him to impregnate her with an unknown man's sperm. Obviously Hattie is a tad insane... not only does she decide to track down and infiltrate her new son's adopted family (with the thought that she is destined to be with her son's father), it also becomes clear that the deaths of her husband Tom and her son Tommy were not accidents.
According to the cover of this paperback, "Horror is born screaming in a novel of breath-stopping danger", but not only was there no build-up of suspense, there was also no sense of tension, and certainly no feeling of horror. It was all very ho-hum, annoying and clichéd. Kind of like an extra-long episode of Days of Our Lives.
Aside from this, Christmas did write a novel with a favourite title of mine: Suddenly in Her Sorbet.