contraception Flashcards
what are the types of COC
classifying by composition
- monophasic: same amounts of estrogen and progestin in every pill
- multiphasic: variable amounts of estrogen and progestin (more estrogen at start and more progestin at end)
classifying by cycle length
- conventional: 21 days active + 7 days placebo
or 24 days active + 4 days placebo
- extended/ continuous: 84 days active + 7 days placebo
what are the absolute c/i of COC
- hx of breast cancer (within past 5 yrs) or current
- acute DVT/PE and on anticoagulants or hx of DVT/PE
- major surgery with prolonged immobilisation
- <21d postpartum (due to risk of DVT)
- migraine with aura
- thrombogenic mutations
- hx of cerebrovascular diseases
- hx of ischemic heart disease or current
- uncontrolled HTN (>160/100)
- HTN with vascular disease
- smoking ≥15 sticks a day and ≥35yo
- cardiomyopathy
what are the common s/e of COC and how to manage them
- breakthrough bleeding (if early/ mid cycle, increase E; if late cycle, increase P)
- N/V (take at night or change to P-only)
- HA (exclude migraine with aura, usually in pill free week, switch to 4 placebo days or extended/ continuous)
- acne (switch to less androgenic P or consider increase E)
- bloating (reduce E)
- breast tenderness or weight gain (keep both E and P as low as possible)
- menstrual cramps (increase P or switch to extended/ continuous)
what to counsel patients on regarding s/e of COC
tend to occur during early COC use, but may improve by third/ forth cycle after adjusting to hormone levels –> advise to try for 2-3m before switching unless serious adverse effects
what are the drug interactions of COC
- rifampin
- ASM
- HIV antiretrovirals
what is the moa of progestin
progestin works to
- thicken cervical mucus to prevent sperm penetration
- slow tubal motility that transports egg from ovary to uterus, to reduce chances of sperm meeting the egg for fertilisation
- endometrial atrophy (thinning of endometrium to make conditions less conducive for egg implantation)
- reduce LH surge from pituitary gland which suppresses ovulation
what are the types of progestin
first gen: norethindrone, norgestrel
second gen: levonorgestrel
third gen: norgestimate, desogestrel
forth: drospirenone
what are the types of estrogen
- ethinyl estradiol
- estradiol valerate
- esterol
- mestranol
what are the doses for estrogen
low: 15mcg
default: 20-25mcg for adolescents, underweight <50kg, >35yo, perimenopausal
moderate: 30-35mcg for obese/ overweight, early to mid cycle breakthrough bleed, spotting, tend to be non adherent
high: ≥50mcg
which progestin is androgenic and which is not and why
- first to third gen are androgenic
- drospirenone is less androgenic as has some anti-androgenic properties, its structural properties reduce binding to androgen receptors and has a K-sparing diuretic effect that can potentially help (but more so with bloating)
how can COC be initiated
- quick start (start now + 7d or longer backup, potentially until next cycle starts)
- sunday start (first sunday after start of cycle + 7d backup, can provide weekend free of cycle)
- first day (first day of cycle)
which component of COC increases the risk of VTE and why
estrogen increases hepatic production of factors VII, X and fibrinogen of coagulation cascade
what are the risk factors for VTE
- > 35yo
- smoking
- obesity
- FMHx
- immobilisation
- cancer
what are the risk factors for ischemic stroke or MI
- age
- HTN
- dyslipidemia
- smoking
- migraine with aura
- obesity
- prothrombic mutations
how to counsel patients on missing COC dose
if missed one dose and <48hrs
- take missed dose immediately and continue the rest as usual (can take 2 in one day)
- no backup needed
if missed two doses
- take missed dose immediately and discard rest of missed doses (can take 2 in one day)
- backup for ≥7d
if missed two doses in the last week of cycle
- finish remaining active pills in current pack, one on each day
- discard hormone free pills
- start new pack once this current pack finished on the next day
- back up contraceptives for ≥7d
