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updated 8/02

Contraception Physiology/Pathophysiology

• Mechanism of Action
• Types of Estrogens
• Types of Progestin's

How do hormone contraceptives work? Physiological mechanism of action

• Combined contraceptives  (oral/transdermal/injection/vaginal ring)
• Depoprovera (depomedroxyprogesterone acetate)

• Progestin's block LH surge, suppress ovulation

• Thick cervical mucus creates barrier

• Alter endometrium for implantation

• Alter tubal motility

Types of estrogens

• Ethinyl estradiol (most potent)
• Mestranol (2/3’s as potent EE)

Types of progestin's (vary in progestin, androgen, estrogen effect)

• Norethindrone
  • Strong estrogenic effect
• Norethindrone acetate,
• Ethynodiol diacetate
  • Low androgenic effect
• Norgestrel
  • strong antiestrogen
  • strong androgenic
• levonorgestrel
• norethynodrel
• desogstrel * *New progestin, 4th generation
• Norgestimate* Less androgenic

Study questions:

• How do the various estrogens and progestin's differ and how do they make various oral contraceptives different?
• How does Depoprovera work as a contraceptive?

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