Oral contraceptives taken by women contain the hormone progesterone.  How does this prevent pregnancy?

A. It stops menstruation.
B. It inhibits the secretion of FSH.
C. It blocks the fallopian tubes (oviducts).
D. It stimulates the production of estrogen.

B

Question 30 was also part of the HL Paper 1. It attracted the similar comments from SL as HL teachers, who contested the answer. Some teachers thought that LH both stimulates follicle development of follicles and ovulation. This view is not supported by the evidence, which shows that LH promotes secretion of estrogen by cells in the developing follicle but that follicle development is stimulated by FSH. The two pituitary hormones FSH and LH have distinctly different roles and it is not correct to lump them together in an explanation of the menstrual cycle. The LH surge is such a good predictor of ovulation for couples wanting to conceive because LH stimulates ovulation.