Contraception 1 Flashcards
Describe the various contraceptive methods that affect each site of the female genital tract (vagina, cervix, endometrium, fallopian tube, and ovary), and the specific mechanism(s) used to prevent conception.
1
Q
List the contraceptive methods that keep sperm out.
A
- Abstinence
- Vasectomy
- Barriers
- male condoms
- female condoms
- diaphragm
- cervical cap
- Spermicides
- Change ovulatory estrogen-dominant mucus
- hormonal contraception
- progestin IUD
2
Q
List the contraceptive methods that prevent ovulation.
A
- Depot hormonal
- progestin injectable
- combo injectable
- progestin implant
- Hormonal
- oral combination
- oral progestin-only
- combination patch
- combination vaginal ring
3
Q
List the contraceptive methods that prevent fertilization.
A
tubal ligation
4
Q
List the contraceptive methods that alter tubal motility.
A
Progestin-only methods
5
Q
List the contraceptive methods that prevent implantation and kill sperm.
A
- Endometrial inflammation
- spermicidal
- impedes implantation
- IUD
- Endometrial atrophy - prevents implantation
- hormonal
- combination
- progestin-only
- progestin IUD
- hormonal
6
Q
Define theoretical efficacy and use effectiveness.
A
-
Theoretical efficacy
- perfect use effectiveness
- consistent and correct use
- without impact of human error
-
Use effectiveness
- typically observed effectiveness
- includes inconsistent and incorrect use
- methods that require daily action have lower adherence reates vs. weekly, monthly, or 5 to 10 yearly
- separation of the act of contraception from the act of intercourse improves efficacy
7
Q
What is the mechanism of action of oral contraceptives?
A
- Progesterone alone is sufficient to inhibit ovulation through suppression of the mid-cycle LH surge
- In combined estrogen and progestin regimens, both hormones work together to inhibit ovulation
-
Additional progestin-induced contraceptive mechanisms:
- endometrial atrophy, which impairs implantation
- thickening of cervical mucus, which impedes sperm migration
- decreased tubal ciliary motility, which alters ovum and blastocyst transport
8
Q
What type of estrogen is given in oral contraception?
A
- Ethinyl estradiol
- most potent estrogen secreted by the ovary
- addition of ethinyl group at the 17-carbon position of estradiol improves oral absorption
- primary estrogen used in most combined oral contraceptive pills
9
Q
What are the characteristics of progestins given for oral contraception?
A
-
Multipel different progestins:
- 19-nortestosterone derivatives
- removal of the 19 carbon from testosterone changes effects to that of progestin
- many adverse effects associated with nortestosterones are from residual interaction with androgen receptors
- ethinyl group to 17-carbon improves oral absorption
- adding cyanomethyl group to 17-C of dienogest (another contraceptive progestin) also improves bioavailability
-
Drosperinone
- chemically related to spironolactone
- both anti-mineralocorticoid and anti-androgen activity
- approved for treatment of acne
10
Q
What are the types of progestins given for oral contraception?
A
-
First generation
- 19-Nortestosterone derivatives
- all first generation compounds metabolized to norethindrone
-
Second generation
- Nortesosterone derivative
- Norgestrel - racemic mixture
- Levonorgestrel - bioactive levo-enantiomer of norgestrel
-
Third generation
- less androgenic and more selective for progesterone receptor
- nortestosterone derivatives
- desogestrel - etonogestrel prodrug to active compound
- gestodene (not US)
- norgestimate
11
Q
What are the common side effects of progestin oral contraceptives?
A
-
Progestin side effects
- androgenic effects from binding of nortestosterones to androgen receptors
- 2nd gen levonorgestrel > 1st gen northindrone >/= 3rd gen norgestimate/etonogestrel
-
most common:
- acne
- oily skin
-
19-Nortestosterone metabolic effects
- increased plasma insulin
- decreased glucose tolerance
- decreased cholesterol, TG, HDL
- increased LDL
- increased sebum production in skin
12
Q
What are the common side effects of progestin oral contraceptives?
A
-
Too much ethinyl estradiol
- breast tenderness
- nausea
- depression, mood lability and/or irritability
- headaches
- melasma
-
EE too low
- endometrial spotting
-
Metabolic effects
- decreased albumin
- increased globulins
- increased angiotensinogen and decreased Na excretion
- increased coagulation proteins
- increased sex hormone binding proteins
- increased TG and HDL
- decreased LDL
- increased skin pigmentation
- increased receptors in breast and endometrium
13
Q
What are the dosing regimens for oral contraceptives?
A
-
Traditionally, 21 days of active pills followed by 7 days of placebo pills
- withdrawal bleed uring the 4th week when estrogen and progestin drop
-
24 days of active pills
- extended regimen better suppresses ovarian follicular development
- decreases break-through bleeding during the rest of the cycle
-
84 days of continuous combined contraceptive pills with a withdrawal period of 7 days every 12 weeks
- regimen reduces frequency of withdrawal bleeding to every 3 months
- associated with increased break-through bleeding during the rest of the cycle
- due to endometrial instability
14
Q
What are side effects related to estrogen dosing?
A
- Ovulation suppression at 20 mcg
- Endometrial control at 30-35 mcg
- Thrombotic complications a >/= 50 mcg
- deep vein thrombosis
- pulmonary embolus
- thrombotic stroke
15
Q
What are some safety risks of oral contraceptives?
A
- Increased risk of venous thrombosis
- probability of death 3rd > 2nd > none
- the greater the increase in SHBG, the greater the risk of thrombosis
- not causal, only a marker
- Increased risk of thrombotic stroke
- only for >/= 50 mcg estrogen
- Increased risk of MI
- smokers over 35 years especially
- Inherited thrombophilia - any dose at risk
- NO proven increases in breast cancer risk
