Contraception Flashcards
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
what is triphasic dosing of combination OC?
fixed or variable EE levels with increasing progestin in all 3 phases to mimic normal cycle
what is extended dosing of combination OC?
planned HFI
>1 “cycle” of active pills then HFI
ex: 84 days of active drug + 7 days EE or HFI
what is continuous dosing of combination OC?
uninterrupted, no HFI
what products can you use for continuous dosing of combination OC?
any product (<50 mcg EE)
oral, transdermal, vaginal
even multiphasic products
T or F
extended/continuous regimens are more forgiving for missed doses?
True
most missed doses occur at the start of a new pack so continuous/extended dosing avoids this issue
when should you start combination OC?
most effective if started on day 1 but can be started at any time
how long should you use back up contraception for after starting combination OC?
if started taking on day 1 = do not need to use back up
if started any other day = use back up for 7 days
what do you do if you miss a pill during week 1 of your cycle?
take 1 pill ASAP and continue as usual to the end of the cycle
consider EC if unprotected sex in last 5 days
use back up protection for 7 days
what is the efficacy of combination OC?
perfect use = <0.3% failure rate
typical use = 3-8% failure rates
what do you do if you miss a pill during week 2 or 3 of your cycle?
take 1 pill ASAP and continue as usual to the end of cycle
start new cycle of CHC without HFI (discard placebo pills if any)
consider EC if 3+ pills missed and unprotected sex in last 5 days
use backup for 7 days if 3+ days missed
what do you do if you miss a pill at the start of a new pack?
resume cycle ASAP
consider EC
use back up contraception for 7 days if EC is indicated
which side effects are common within the first 3 months of starting combination OC?
breakthrough bleeding
breast tenderness
nausea
what are most side effects of combination OC caused by?
estrogen
what do you do if breakthrough bleeding lasts for more than 6 months on combination OC?
check adherence
look for other causes (STI)
change to pill with increased estrogen/progestin (depending on when BTB occurs)
in first phase = increase estrogen
in second phase = may be due to progestin
what are the side effects of combination OC?
weight gain
headache or migraine – can either increase or decrease with use
mood changes – depression
acne – usually do to progestin – some help
how can some combination birth controls help reduce acne?
lowers amount of endogenous androgens produced or (bio)available (androgens stimulate sebum production = acne)
what are the benefits of combination OC?
simple and effective
improves menstrual symptoms and regularity: decreases dysmenorrhea, ovulation pain, PMS symptoms
decreases incidence of: endometriosis, endometrial cancers, ovarian cancer, ovarian cysts, osteoporosis (increases bone density), acne and hirsutism
what are some risks involved with combination OC?
contraception failure
venous thromboembolism (VTE)
MI and stroke (arterial thrombosis)
breast cancer
cervical cancer
what increases the risk of VTE and arterial thrombosis on combination OC?
increased age
higher estrogen dose
smoker
HTN
T or F
common antibiotics may reduce the efficacy of birth control
False
not really a problem (with the exception of rifampin)
what are the 3 types of potential DI with OCP?
drugs that reduce enterohepatic circulation (Abx)
drugs that induce metabolism
metabolism altered by oral contraceptives
which drugs interact with OCP by inducing metabolism?
anticonvulsants (carbamazepine, phenytoin)
anti-infectives (rifampin)
herbals (St. Johns wart)
how to deal with DIs of OCP due to induction of metabolism?
use product with higher estrogen levels (>30 mcg EE)
use extended dosing (skip HFI)
use alternative to interacting drug or other method of birth control (do not change anti-convulsants)
which drugs metabolism is altered by OCPs?
lamotrigine
significantly lowers levels - induction of lamotrigine glucuronidation
what are CI of combination OC?
thromboembolic disease (current or past VTE)
ischemic heart disease/stroke
migraine with aura = increase in clots
smokers (>15 cigs/day) over 35
HTN (>160/100)
known or suspected breast cancer
severe/acute liver disease
post partum
how long after having a baby do you have to wait until you can take combination OC and why?
3-6 weeks post partum
increase risk of VTE
what amounts of hormones are in the transdermal patch (Evra) and how much is released each day?
0.6 mg EE + 6.0 mg norelgestromin?
average daily release of 35 mcg EE and 200 mcg norelgestromin
what is the efficacy of Evra?
perfect use = failure rate of 0.3-0.7%
typical use = failure rate of 8%
when should you start using Evra?
most effective if started on day 1 of cycle but can start at any point
for how long should you be using back up contraception after starting Evra?
if started on day 1 = no back up needed
if started any other day = back up for 7 days
how do you use Evra?
1 patch applied weekly = 3 weeks then no patch for 1 week (HFI)
applied to upper arm, buttock, lower abdomen, upper torso
what are the adverse effects of Evra?
similar to combination OC
local skin irritation
can have increased spotting in first 2 cycles
less effective and increase risk of clots if weigh >90 kg (200 lbs)
what are DI with Evra?
similar to combination OC
rifampin, lamotrigine, anticonvulsants, etc.
how much hormones are released daily with Nuvaring?
15 mcg EE+ 120 mcg etonogestrel released daily
what is the efficacy of the Nuvaring?
perfect use = failure rate of 0.3-0.8%
typical use = failure rate of 8%
how do you use the Nuvaring?
insert (anywhere in the vagina), leave in for 3 weeks then remove for one week (HFI)
how long should you use back up contraception for after starting the Nuvaring?
if started on day 1 = no back up needed
inserted on any other day = use backup for 7 days
how long can you leave Nuvaring out for during cycle?
less than 3 hours
what are some adverse effects of Nuvaring?
similar to combination OC
vaginitis
foreign body sensation/discomfort
problems during sex (can remove during sex then reinsert)
how do you store nuvaring?
store in fridge in pharmacy
stable at room temp for 4 months