Contraception Flashcards
what are the modern methods of contraception?
- female and male
sterilization - oral hormonal pills
- the intra-uterine device (IUD)
- male and female condoms
- injectables
- the implant (including Norplant)
- vaginal barrier methods
- emergency contraception.
what are traditional or natural methods of contraception?
- rhythm (periodic abstinence)
- withdrawal
- lactational amenorrhoea
method (LAM)
What are the different family planning (contraception) methods? what is their effectiveness and reversibility?
- male condom (18% - reversible)
- female condom (21% - reversible)
- withdrawal (22% - reversible)
- fertility awareness-based method (24% - reversible)
- sponge (12-24% - reversible)
- spermicide (28%- reversible)
- injectable (6% - reversible)
- pill (9% - reversible)
- patch (9% - reversible)
- ring (9% - reversible)
- diaphragm (12% - reversible)
- implant (0.05% - reversible)
- IUD (0.12% - reversible)
- female/male sterilization (0.15% (male) and 0.5% (women) - irreversible)
what are the main components of the endocrine system regarding male and female reproduction?
- GnRH produced and released by hypothalamus
- goes to anterior pituitary where it releases LH and FSH
- goes to testes or ovary where hormones are produced
what is a hormone?
a chemical messenger that circulates in the body and has an effect on distant cells
explain the hypothalamic-pituitary-ovarian axis with their feedback loops.
- hypothalamus releases GnRH and stimulates pituitary
- releases LH and FSH, which stimulates ovary
- stimulates maturation of ovarian follicles and production estrogen and progesterone
- estrogen has negative feedback on hypothalamus
- progesterone has negative feedback on pituitary
is GnRH, LH, and FSH released in a constant way?
no they are released in a pulsatile way
on which cells does LH act on and what does it do? (In women)
- acts on theca cells
- increases steroid synthesis
- increases amount of FSH receptors
on which cells does FSH act on and what does it do? (In women)
- acts on granulosa cells
- regulates follicle growth and maturation
- increases activity of cholesterol side chain cleavage (by CYP11A1 – to make progesterone)
- increases activity of aromatase (to make estradiol)
What is the action of progesterone?
two response types:
- slow genomic process where receptor goes to nucleus and activates genes
- fast nongenomic process where receptor activates secondary messengers
what are the two types of estrogen receptors and what do they do?
- ER-alpha: leads to nuclear response
- ER-beta: leads to nongenomic response
what are the uses of estrogens and progestins as drugs?
- contraception
- ovulation control
- hormone replacement therapy
- cancer chemotherapy
what is the positive feedback regulation seen when looking at the menstrual cycle?
- estradiol concentration increases above a threshold (right before ovulation –after menses)
- this triggers GnRH
- this causes the LH surge
what is the effect of the LH surge in ovulation regulation?
it stimulates follicle rupture and ovulation
what is the negative feedback regulation seen when looking at the menstrual cycle?
- after ovulation there are high levels of estradiol, which causes negative feedback so decreases levels of FSH and LH
- corpus luteum releases high levels of progesterone, so there is an increase in luteal phase, which causes even further inhibition of FSH
how does fertility-awareness based contraceptive methods work?
basal body temperature is lower during follicular phase and higher during luteal phase due to progesterone levels
what are the different types of oral contraceptive pills?
combination pills: contain both estrogen and progestin analogues
- monophasic: 1 month cycle (all pills are the same)
- multi-phasic: active pills contain different amounts
- extended cycle: typically 12 weeks of active pills
progestin-only pills
How do oral contraceptives pills work?
- prevent the ovary from releasing an egg
- thicken the cervical mucus to make it difficult for sperm to reach the egg
- thin the lining of uterus to make implantation of a fertilized egg more difficult
what is perfect use failure rate of contraceptive pills vs typical use rate? why is this seen?
- perfect: 0.3%
- typical: 9%
- due to poor compliance
What are different drug-drug interaction mechanisms which may affect oral contraceptives?
- induction of P450s: would metabolize hormone faster
- entero-hepatic circulation change: affects absorption and distribution
- binding to plasma proteins
what are advantages of oral contraceptive pills?
- periods more regular
- can be used for women over age 40
- may decrease menstrual cramps, bleeding, anemia
- may be associated with decreased risk of ovarian and endometrial cancer, and colorectal cancer
- may decrease breast tenderness and acne
- does not interfere with sexual intercourse
- may increase bone density