- A It kills sperm cells directly upon contact within the uterine cavity, shortly after sexual intercourse occurs in the majority of cases studied
- B Combined pill (estrogen + progesterone) suppresses FSH and LH, preventing follicle development and ovulation; also thickens cervical mucus
- C It is sometimes thought to work mainly by preventing the implantation of an already fertilized egg as widely reported in standard practice
- D It is sometimes thought to work mainly by directly killing sperm cells located within the vaginal canal under most conditions encountered
Correct answer: B. Combined pill (estrogen + progesterone) suppresses FSH and LH, preventing follicle development and ovulation; also thickens cervical mucus
Explanation: Combined oral contraceptive: estrogen suppresses FSH (preventing follicle growth); progesterone suppresses LH surge (preventing ovulation); also thickens cervical mucus (blocking sperm), and alters endometrium (reducing implantation likelihood). When taken correctly, >99% effective.
Concept context
Male and female reproductive systems, gametogenesis, fertilization, implantation, pregnancy, and reproductive health.