Contraception Flashcards
(162 cards)
what are the 5 main hormones involved in the menstrual cycle?
gonadotropin release hormone (GnRH)
follicle stimulating hormone (FSH)
estrogen (mainly estradiol)
luteinizing hormone (LH)
progesterone
what is the role of gonadotropin release hormone (GnRH) in the menstrual cycle?
stimulates pituitary to release FSH and LH
what is the role of follicle stimulating hormone (FSH) in the menstrual cycle?
stimulates maturation of follicles in ovaries
what is the role of estrogen in the menstrual cycle?
stimulates thickening of the endometrium
suppresses FSH (negative feedback)
signals LH
what is the role of luteinizing hormone (LH) in the menstrual cycle)?
triggers ovulation
what is the role of progesterone in the menstrual cycle?
makes the endometrium favourable for implantation
signals the hypothalamus and pituitary to stop FSH and LH production (negative feedback)
where is progesterone produced?
produced by the corpus luteum: mass of cells resulting from ruptured follicle when the ovum is released
how long is the average menstrual cycle?
28 days
what day of the menstrual cycle is the first day of the period?
day 1
what are the two phases of the menstrual cycle?
follicular phase and luteal phase
when is the follicular phase?
starts on day 1
is typically around 14 days but can vary
what occurs during the follicular phase?
day 1: first day of period
day 3-4: increase FSH (follicle grows/develops)
day 5-7: one follicle becomes dominant and starts producing estradiol
stops menstrual flow
stimulates thickening of endometrial lining
increased production of thin, watery, cervical discharge
consistently high estrogen levels stimulate the pituitary to release a mid cycle surge of LH
LH = follicle maturation and triggers ovulation
when does ovulation occur?
about 28-32 hours after the LH surge (in the follicular phase)
when is the luteal phase
occurs after ovulation
always 14 days
what occurs during the luteal phase?
released ovum travels through fallopian tubes to the uterus
“left over” follicle becomes corpus lumen
produces androgens, estrogens, and progesterone
progesterone provides negative feedback to stop FSH and LH
maintains the endometrial lining
what occurs to the corpus luteum if no implantation occurs?
corpus luteum deteriorates and stops producing progesterone
what occurs to the corpus luteum if implantation occurs?
corpus luteum continues to produce progesterone but that function is ultimately taken over by the placenta
what happens after the luteal phase if no implantation occurs?
progesterone levels decrease –> follicular phase
endometrial lining is shed (menses)
low progesterone and estrogen levels stimulate the release of GnRH and cycle starts all over again
what are the 2 forms of estrogen available in contraception?
ethinyl estradiol (EE): synthetic form of estradiol, most common
estetrol: plant source
what are progestins?
synthetic hormones that activate progesterone receptors
which progestins are anti-androgenic?
cyproterone acetate
drosperinone
what is the MOA of combination hormonal contraception?
estrogen and progestin provide negative feedback which inhibits ovulation
estrogen: suppresses release of FSH
progestin: suppresses release of LH and FSH; thickens cervical mucous (impedes sperm transport); changes endometrial lining (not hospitable to implantation)
what is monophasic dosing of combination OC?
fixed levels of EE and progestin
what is biphasic dosing of combination OC?
fixed EE levels with increased progestin in 2nd phase