The obstetrical nurse knows that a woman's hormone levels change dramatically during pregnancy. Which of the following hormonal actions accurately represent these changes?

a) Maintaining the endometrium so that the embryo can implant
b) Causing changes in the mother's metabolism so that nutrients are available for both
c) Preparing the breasts for lactation, keeping the milk from coming in until birth occurs
d) Relaxing the ligaments that connect the pelvic bones, allowing them to spread slightly
e) Decreasing the blood supply to the gastrointestinal tract and slowing peristaltic waves
f) Decreasing the mother's blood volume and red blood cell mass to increase oxygen