Final answer:
Beta-hCG levels typically decrease in the event of a spontaneous abortion or miscarriage, as the hormone is produced by the chorion of the zygote to support the pregnancy, which is no longer viable.
Step-by-step explanation:
How do beta-hCG levels change with spontaneous abortion? In the case of a spontaneous abortion, also known as a miscarriage, beta-hCG (human chorionic gonadotropin) levels typically decrease since the developing pregnancy is not sustained. Beta-hCG is a hormone produced by the chorion of the zygote which helps maintain the corpus luteum and thus keeps progesterone levels elevated to support a pregnancy. Normally, beta-hCG levels increase rapidly during the early stages of pregnancy, but if a miscarriage occurs, the trophoblastic tissue that produces beta-hCG is lost, leading to a decline in hormone levels. This drop in beta-hCG is one of the indicators that can be used to confirm a miscarriage has occurred. Conversely, should a successful treatment or intervention, such as chemotherapy or surgical removal in the case of gestational trophoblastic disease, lead to a resolution of the abnormal tissue, a corresponding fall in beta-hCG levels would also be observed.