Contraception Physiology
Start with the big picture
Combined hormonal contraceptives provide negative feedback that lowers FSH and LH, inhibiting follicle development and ovulation. Estrogen primarily suppresses FSH, while progestin suppresses LH and thickens cervical mucus. Progestin-only methods also affect cervical mucus and the endometrium, and may suppress ovulation; they are suitable for lactating women. Emergency contraception includes levonorgestrel, ulipristal, and the copper IUD, each described through its effects on the LH surge, ovulation, or fertilization and implantation. Barrier methods prevent sperm from entering the cervix, with condoms the only barrier method noted as offering STI protection. Copper and levonorgestrel IUDs act through different local mechanisms, while tubal ligation and vasectomy prevent sperm and egg from meeting or sperm from being transported.
What you'll learn
- Explain how combined hormonal contraceptives affect FSH, LH, follicle development, and ovulation.
- Describe the actions of progestin-only methods on cervical mucus, the endometrium, and ovulation.
- Distinguish the mechanisms of levonorgestrel, ulipristal, and copper IUD emergency contraception.
- Compare barrier methods and IUDs by their mechanisms of action.
- Describe how tubal ligation and vasectomy prevent pregnancy.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
