Source of estrogen and progesterone

Which of the following is the source of estrogen and progesterone during the last seven months of pregnancy?

A. Ovary 

B. Placenta
C. Corpus luteum
D. Anterior pituitary

Answer is B. 

During the first two months of pregnancy, estrogen and progesterone production is primarily the responsibility of the corpus luteum. The placenta serves as the source of the hormones during the remainder of pregnancy Progesterone is essential to maintain placental implantation, inhibit uterine contractions, and suppress the maternal immune system response to fetal antigens. Estrogens serve to increase the size of the uterus, induce progesterone and oxytocin receptors, stimulate maternal hepatic protein secretion, and promote breast development. Estriol is the major estrogen produced during pregnancy The production of estrogen and progesterone during gestation requires cooperation between the maternal, placental, and fetal compartments—the fetoplacental unit.