Contraception Flashcards
Physiology of the Normal Menstrual Cycle
- is regulated by positive and negative feedback in the hypothalamic-pituitary-ovarian axis
- gonadotropin-releasing hormone (GnRH) pulses regulate follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which in turn, regulate the secretion of estrogen and progesterone from the ovary
Four Phases of the Menstrual Cycle
- Follicular
- Ovulatory
- Luteal
- Menstrual
Follicular Phase
- first phase of menstrual cycle
- FSH stimulates several follicles to develop
- the dominant follicle synthesizes enough estradiol to create negative feedback and decrease FSH levels
Ovulatory Phase
- second phase of the menstrual cycle
- estradiol levels peak and exert positive feedback to induce an LH surge, which facilitates release of the mature ovum
- estrogen promotes proliferation of the endometrium and development of progesterone receptors in the endometrium
Luteal Phase
- third phase of the menstrual cycle
- progesterone prevents new follicle development as well as differentiation of the endometrium
- if no pregnancy, the corpus luteum degenerates, leading to menstrual bleeding
Estrogen
- has positive effects on bone mass, increases serum triglycerides, and improves ratio of high-density lipoprotein to low-density lipoprotein
- stimulates coagulation and fibrinolytic pathways
Progesterone
- increases body temperature and insulin levels
- may depress the CNS
Estrogen Contraceptives
- Ethynyl estradiol
- Mestranol
Examples of 1st Generation Progesterones
- Norethindrone
- Norethindrone acetate
- Ethynodiol diacetate
Examples of 2nd Generation Progesterones
- Norgestrel
- Levonorgestrel
Examples of 3rd Generation Progesterones
- Desogestrel
- Norgestimate
Examples of 4th Generation Progesterones
- Spironolactone derivative: drospirenone
- 19-nortestosterone derivative: dienogest
Mechanisms of Pregnancy Prevention
- progestins are primarily responsible for the contraceptive effect
- progestins exhibit a negative effect in the hypothalamic-pituitary-ovarian axis
- progestins cause atrophy of the endometrium, preventing implantation
- the estrogen component improves efficacy by suppressing FSH release
- estrogen provides cycle control
Goals of Contraceptive Treatment
- use the safest, best-tolerated, and most effective method that the patient desires
- safety
- tolerance
- effectiveness
Fine Tune Contraceptive Drug Selection Based on
- menstrual pattern
- side-effect profile
- patient’s desire for discretion
- timing of subsequent pregnancy
Contraceptive Drug Selection: Cost
- retail cost of OC (oral contraception) is $30 to $100 per cycle
- generic OC is available on $4 retail lists
- intrauterine device (IUD) or implant: upfront cost is expensive, but may have lower overall cost
Non-contraceptive Benefits
- decreased dysmenorrhea, menstrual irregularities, and menstrual blood loss
- lessening of acne and hirsutism
- fewer ovarian cysts
- significantly reduced endometrial and ovarian cancer risk
- lower incidence of benign breast conditions, such as fibrocystic changes and fibroadenoma
- reduced risk of hospitalization for gonorrheal pelvic inflammatory disease
- suppression of endometriosis in women who do not currently desire pregnancy
Contraceptive Drug Interactions
- TB drugs
- antiepileptic drugs
- St. John’s Wort
Contraceptive Drug Adverse Reactions
- venous thromboembolism risk increases three to five times with OC use
- cholestatic jaundice
- benign hepatic neoplasms
- myocardial infarction
- stroke
- neurological migraines
Traditional OC Regimen
- 21 days active drug + 7 days inactive tablets with withdrawal bleed during inactive tablets
Extended Cycle OC Regimen
- 84 days of active drug, then 7 days off
- withdrawal bleed once every 3 months
Monophasic
- same dose of estrogen and progestin for full cycle
Biphasic
- vary the dose of progestin
Triphasic
- vary the dose of estrogen, progestin, or both
OC First Day Start
- pills started on first day of menstrual cycle
- no backup method needed
OC Sunday Start
- first pill taken on the Sunday following the start of menses
- back method for first 7 days
- menses only occur during the week
OC Quick or “Same Day” Start
- first pill taken on the day of the office visit
- back up method needed for the first 7 days
OC Patient Education
- what to do if doses are missed
- 50% of women discontinue because of the side effects
Contraceptive Topical Patch
- Ortho Evra patch: releases 20 mcg of estrogen and 150 mcg of norelgestromin
- patch applied weekly for 3 weeks, then 1 week off
- start on first day of menses (can start other days if back up method is used)
- ADRs similar to OC ADRs
- Increased failure rate in women weighing more than 198lb
Vaginal Ring
- NuvaRing is a soft, flexible plastic ring that releases 15 mcg of estrogen and 120 mcg of etonogestrol daily
- ring is placed in the vagina, left in place for 3 weeks, and then is left off for 1 week
- better cycle control and decreased breakthrough bleeding are achieved compared with OC
- systemic exposure to estrogen is lower
Progestin Only Pills
- these are used when estrogen is contraindicated
- contraceptive effect is through thickening of cervical mucus and prevention of sperm penetration
- users have to be diligent about taking dose daily at the same time (if a pill is taken even a few hours late, back up is recommended for the next 48 hours)
- ADRs: changing bleeding patterns and breast tenderness are common
Injectable Progestins
- depot medroxyprogesterone acetate (Depo-Provera) is a long-acting, injectable progestin-only contraceptive
- one injection is effective in suppressing ovulation for 12-13 weeks
Advantages of Injectable Progestins
- once every 12 week dosing
- effective
Disadvantages of Injectable Progestins
- spotting, followed by amenorrhea
- weight gain
- depression
- black box warning: decreased bone density with longer-term use
Mirena IUD
- releases 20 mcg of levonorgestrel daily
- can be left in place for 5 years
- only small levels of systemic circulating hormone and minimal systemic side effects
- changes in menstrual bleeding, amenorrhea
Implanon
- an implantable rod that contains 68 mg of etonogestrel
- provides contraception for up to 3 years
Emergency Contraception
- should be implemented as soon as possible (less than 72 hours) after unprotected intercourse
- may be initiated up to 120 hours after
Methods of Emergency Contraception
- Combined OCs
- Progestin only (Plan B and Next Choice)
- Copper IUD
Monitoring
- routine female screening
+ history
+ breast and pelvic examinations
+ Papanicolaou (“Pap”) test and sexually transmitted infection testing
+ blood pressure - physical examination, breast examination, pelvic examination, and PAP testing not required for contraception prescription
- BP and ADRs monitored at 3 months, then annually