Contraception Flashcards
aim of contraception
prevent fertilization of an ovum by sperm. prevent the transport of a developing pre-embryo and its implantation in the uterus
name modes of contraception
- hormonal
- emergency
- intrauterine devices
- spermicides
- barrier
- coitus interruptus
- coitus reservatus/obstructus
- rhythm
- breast feeding
target of hormonal contraception?
override natural endocrine patterns
- inhibit ovulation in women
- inhibit spermatogenesis in men
ovulation doesnt occur when?
-> common area?
luteal phase + pregnancy
common: high P , moderate E. (-) feedback on hypothal + pit.
how hormonal contraception works?
exogenous P mimic effects of:
- hypothal releasing less GnRH
- decrease FSH to slow follicular growth
- decrease LH to inhibit ovulation
= override natural hormone cycle, prevent ovulation + maintain luteal phase
delivery of hormonal contraception
- composition
- regimen?
- injectable
- oral pill
- transdermal patch
- ring
usually in form of progestin in combo with Estrogens
- 3 weeks on, 1 week off = withdrawal bleeding
Combination hormone treatment
- progestin effective as contraceptive. but has side effects.
- add E to stabilize endometrium = reduce breakthrough bleeding.
- E adds additional hypothalamic/pituitary feedback
history of combination pill
- approved in 1960: most commonly used reversible method – no reports of irreversible changes
- over 60 types now. all with synthetic E+P. varying amounts, diff potency
combination pill - mode of action
- inhibit tertiary ovarian follicle growth (no granulosa cell fxn, no E surge, prevent LH surge +ovulation)
- cervical mucus hostile (impermeable, too thick) for sperm transport
- uterine endometrium unreceptive to embryo (E:P not sufficient to support implantation
withdrawal bleeding of combination pill
- pregnancy unlikely bc embryo unlikely to implant.
- endometrium unhospitable, 7 days off isnt enough time for FSH rise, follicular growth + LH rise to = ovulation
miss a dose of combination pill?
- one missed, take two the following day
- missed 2+ days, cease for 7 + allow withdrawal bleed. “waiting period” + need alternative contraception
types of combination pills
monophasic - all active has same dose
bi-/tri-phasic: mimic changing hormone levels in natural cycle.
- as effective as monophasic
- useful if have certain concerns/side effects
seasonale and lybrel - combination pills
seasonale: 91 day pill sequence. fixed dose of E+P for 84 days, 7days off.
lybrel: 1 year combined oral contraceptive pill. continuous dose, no break. completely eliminates menstrual flow
