Steroidal Contraceptives

• Oestrogen receptors (a and b) are dimers
• Oestrogen and progesterone act by influencing gene transcription
• COCP MOA: Suppression of FSH release to prevent follicle development
• Progesterones cause what effects?

  Secretion of thick cervical mucus

  Inhibits motility of fallopian tube
• Oestrogen causes what effects?

  Enhances fallopian tube motility

  Inhibits ovulation by blocking gonadotrophin surge
• POP MOA- low dose:

  Stops asynchronous development of endometrium

  Decreased fallopian tube motility

  Thicker cervical mucus production
• POP MOA- High dose: Inhibits follicular development and ovulation
• 3rd generation COCP have less androgenic activity
• Monophasic preparations = fixed amounts of oestrogen and progesterone (28 days on 7 days off)

  Biphasic = progesterone increased once

  Triphasic = progesterone increased twice
• Oestrogen conc should be lowest which maintains cycle control with no breakthrough bleeding
• Transdermal patch = apply weekly for 3 weeks and then 7 days patch free.

  Contains Ethinylestradiol and norelgestromin
• Vaginal ring contains ethinylestradiol and etonoregestrel
• IM injections MOA (depo progesterone) : Inhibit Ovulation
• Medroxyprogesterone acetate (DEPO) can cause osteoporosis if used long term
• SC implant of Etongestreol
• IUS releases levonorgestrel over 5 years]
• Levonorgestrel = emergency contraception within 72 hours. Causes nausea and MOA= inhibits ovulation
• Ulipristal acetate = emergency contraception within 120 hours. MOA = suppresses mature follicle
• Insertion of Copper IUD = emergency contraception within 5 days.