All of the following statements concerning pregnancy are accurate except:

• A. The detection of human chorionic gonadotropin in the urine forms the basis for pregnancy tests.
• B. The cyclic release of pituitary gonadotropins and ovarian steroids is continued.
• C. The mammary gland tissue of the pregnant woman is stimulated to develop by placental hormones.
• D. The corpus luteum of pregnancy maintains the uterus until the placenta is well established.