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Physiology of menstrual cycle
- Typically 28 d cycle
- First half is first 14 days - follicular phase - follicles are recruited and one becomes dominant - stimulated by FSH which is higher in follicular phase - inverse relationship with estrogen
- Second half is next 14 days - luteal phase - increase in estrogen triggers LH spike around day 14 and ovulation occurs - LH and FSH then stay low and estrogens and progestins are high
- If fertilization doesn't occur, estrogen and progestin levels decrease and eventually the endometrium sheds - menstruation
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MOA of combination oral contraceptives
- Estrogen component inhibits FSH secretion preventing the development of a dominant follicle
- Progestin component inhibits LH surge, preventing ovulation; creates atrophied endometrium unreceptive to implantation; thickens mucus to interfere with sperm transport; alters fallopian tube secretions making it harder for the egg to travel
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Advantages and disadvantages of combination OCs
- Advantages:
- less iron deficiency anemia
- decreased cramps
- decreased rate of ectopic pregnancy
- decreased PID rate by 60%
- protection vs. endometrial and ovarian cancer by 40-50%
- suppression of development of functional ovarian cysts
- protection vs. fibrocystic breast disease by 40%
- increased bone mineral density
- less menstrual cycles
- Disadvantages:
- compliance
- increased risk of thromboembolism and stroke
- increased TGs
- increased BP
- no STD protection
- increased risk of benign hepatocellular adenomas
- possible increase in breast cancer risk
- conflicting results re: cervical cancer risk
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SEs d/t excess estrogen
- nausea
- bloating/edema
- cervical mucorrhea, polyposis
- HTN
- migraines
- breast tenderness/fullness
- (like pregnancy sx)
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Sx d/t deficiency of estrogen
- Breakthrough bleeding early to mid cycle (days 1-10)
- hypomenorrhea
- increased spotting
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Sx d/t excess of progestin
- increased appetite
- wt gain
- tiredness, fatigue
- hypomenorrhea
- acne, oily scalp
- hair loss, hirsutism
- depression
- monilial vaginitis
- breast regression
- (androgenic SEs)
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Sx d/t deficiency of progestin
- Breakthrough bleeding in late cycle (days 10-28)
- amenorrhea
- hypermenorrhea
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Counseling on combination OCs
- Dosing regimen
- Compliance
- When birth control effective
- Missed doses (one - take as soon as remember then take next one at normal time that day - alternative methods unnecessary; missed two - take two on day remembered and take two the next day - use backup method for rest of cycle; missed more than two - start a new pack like first starting - start on Sunday if a Sunday starter, or others just begin immediately - use backup method for whole cycle)
- Adverse effects
- ACHES - abdominal pain, chest pain, headaches, eye problems, severe leg pain
- No protection vs. STDs/HIV
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Counsel on "morning after" emergency contraception
- Prevents implantation
- Plan B One Step or Next Choice - otc for women > 17 - can take 2 tabs together or separate by 12-24 h
- Ella - rx only - also delays ovulation - progesterone receptor antagonist/agonist
- Others - 2-4 doses of OCs
- Efficacy 79-85%
- WHO recommends levonorgestrel only
- Use within 120 hours of unprotected intercourse (< 72 h is better)
- ACHES
- Nausea, vomiting
- Would not prevent ectopic pregnancy
- Teratogenicity unknown
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Advantages and disadvantages of progestin-only contraceptives
- Advantages:
- May be used in lactating women
- may be used in women with CV risk, HTN, HAs, smokers, CVA, liver impairment/tumor, current DVT
- avoids estrogen SEs
- decreased PID rate
- Disadvantages:
- usually d/t too little estrogen
- increased amenorrhea or freq spotting
- increased risk of ectopic preg because ovulation not inhibited
- not as many MOAs - efficacy d/t endometrial and cervical mucus changes
- may incr risk of T2DM in pts who had gestational diabetes
- must take qd @ same time - if dose missed, backup needed
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IM progesterone advantages and disadvantages
- Advantages:
- low failure rate (higher dose, so 4 MOAs)
- decr or no menses or cramps
- decr yeast infx, ectopic pregnancy, PID
- no suppression of lactation (may give 6 wk postpartum)
- no incr risk of thromboembolism - ok to use with HTN, CV risk, etc
- passive
- no estrogen SEs
- Less drug intx
- may be alternative for pts on anticonvulsants
- Disadvantages:
- return of fertility possibly delayed (10-18 mo)
- breakthru bleeding possible
- weight gain
- decreased HDL, increased TG
- office visit required
- decr bone mineral density (BBW to limit use to < 2 yr and add Ca and D)
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Counsel on a progestin only contraceptive
- Dosing regimen - start on first day of menses
- Compliance v. important - qd, same time
- Back-up protection until next menses
- Missed dose: even if 3 h late, must use another method for next 48 h. If missed 2 + doses, skip missed doses and use a backup method until next menses
- AEs
- No protection vs STDs/HIV
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