Contraception Flashcards

1
Q

What are contraceptives?

A
  • block conception of a fetus
  • keep sperm and egg from becoming united
  • eg. combo OC pills, mini-pills, progesterone injections, contraceptive patches, and mechanical methods like caps and condoms
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2
Q

What are contragestational agents?

A
  • keep gestation from occuring
  • work to keep fertilized egg/zygote from implanting
  • IUD, morning after pill
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3
Q

What are abortifacients?

A
  • cause the termination of an established pregnancy
  • mifepristone, mechanical means of abortion
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4
Q

What are the necessary steps that need to happen to become pregnant? How can these steps be interrupted?

A
  • production of viable sperm
  • transport of viable sperm (vasectomy)
  • deposit into the posterior fornix of vagina (condoms or coitus interruptus)
  • survival of sperm in vagina before going up cervix and into uterine tubes (spermicide)
  • movement of sperm into uterine tubes (cervical cap and diaphragm to block entry through cervix)
  • production of viable oocytes (OC pills)
  • ovulation (OC pills)
  • movement of oocytes to uterine tube (tubal ligation)
  • fertilization of oocyte with sperm
  • implantation of oocyte (MAPs, OCs, IUDs)
  • growth of embryo/fetus (abortion- surgical or medical)
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5
Q

Describe the preparation of the endometrium

A
  • menstrual phase (day 1-4) where functionalis layer comes off
  • proliferative phase (day 4-14) driven by the development of the oocytes from primary into secondary follicles
  • secondary follicles make estrogens which causes endometrium to grow (more vascularization and glands), cervical mucus is thin
  • corpus hemorrhagicum at 14 days which signals beginning of secretory phase
  • corpus luteum makes estrogen and progesterone
  • uterine gland cells are producing the maximal amount of secretions for the zygote and the cervical mucus is thick
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6
Q

What are calendar methods of birth control (fertility awareness)?

A
  • fertility awareness relies on noticing the signs of ovulation
  • slight drop in body temperature occurs just before ovulation and slight increase in body temperature that occurs after
  • production of thin, clear, watery and elastic cervical mucus (max spinnbarkeit) that shows maximal ferning
  • mittelschmerz (one-sided cyclical abdominal pain associated with ovulation)
  • position of the cervix (lower harder cervix=less fertile, elevated, softer and wetter cervix= more fertile)
  • intercourse has to be planned around the times when ovulation is not going to occur
  • a number of cycles have to be recorded to be reasonably sure that the cycle is regular
  • about a 20% failure rate per year though with perfect use it could be 2% (sex drive is up during ovulation so perfect use can be hard, other things can alter cervical mucus that aren’t ovulation)
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7
Q

What are calendar methods of birth control (rhythm method)?

A
  • practice abstinence from sexual intercourse 3 days before and 3 days after likely date of ovulation
  • date of ovulation determined from menstrual cycles
  • failure rate is 9% per year but more like 25% in typical use
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8
Q

What is a symptothermal chart?

A
  • body temperature is recorded; around day 13-14 temperature dipped and increased indicating ovulation
  • blood during menstrual phase, no discharge in proliferative phase, discharge because of thin cervical mucus, at ovulation becomes wet, clear, and slippery, after ovulation flip flops between discharge/no discharge and discharge becomes dry/pasty/cloudy which means it is unlikely sperm will get through
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9
Q

What is cervical mucus ferning?

A
  • when cervical mucus dries it makes ferning pattern from crystals
  • fertility awareness method can rely on this
  • if you are infertile, the cervical mucus won’t fern up
  • can look at it with a fertile focus
  • these methods can be popular because they monitor the normal cycle rather than changing it (OCs, patch, and injection look to manipulate hormone levels and ovarian/uterine cycles)
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10
Q

How do combination pills function?

A
  • combine an estrogen and a progestin to create a psuedopregnancy
  • estrogen and progestin inhibit release of GnRH
  • this suppresses hypothalamo-pituitary-gonadal axis; low GnRH-low FSH/LH-little follicle development/no LH surge (no ovulation)
  • create a thick cervical mucus which inhibits sperm migration
  • “hostile” endometrium
  • the endometrium is not in the secretory phase (it is atrophic) thus it does not allow the zygote to implant
  • endometrium does not build up because the combo of estrogen and progestin is not what you need to grow endometrium
  • endometrium is thin like this in pregnancy
  • one of the most effective reversible types of birth control
  • failure is 0.7 per woman years
  • one or two pills are enough to cause the endometrium to proliferate and allow ovulation
  • most combination preparations involve taking 21 days of hormones and 7 days without hormones where endometrium will likely come off (withdrawal bleed)
  • some pills have extended the time between withdrawal bleeds
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11
Q

Why do the combination pills cause women to have more bleeding episodes than in history?

A
  • historically, women married and started having intercourse young
  • they would get pregnant then exclusively breastfeed the child
  • effects of prolactin during breastfeeding prevent ovulation
  • every few years a child would come along
  • relatively few cycles because they are pregnant and lacting more often
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12
Q

How does the contraceptive patch work?

A
  • work the same as OC except the delivery of steroids is transdermal
  • this should allow for low levels of steroids since the drug enters the system very slowly
  • it is hard to be uncompliant with this system unless the patch falls off
  • the patch is put on once a week
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13
Q

How does the contraceptive ring work?

A
  • combined steroid contraceptives
  • it is put into the vagina for three weeks and removed for one
  • it does not provide any sort of barrier to the movement of the sperm, it is just a way to deliver steroids
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14
Q

What are injectable combined contraceptives?

A
  • medroxyprogesterone acetate and estradiol cypionate are combined in a once monthly injection
  • sold as Lunelle or Cyclofem
  • not available in US or Canada though it was available for a while in the US
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15
Q

What is progestin-only contraception?

A
  • formulated to avoid the side effects of estrogen (mainly nausea and vomiting but also breast tenderness and increased rates of deep vein thrombosis)
  • do not reliably suppress ovulation but cause thick and scanty cervical mucus and prevent the movement of sperm across the cervix
  • the endometrium is also kept in a pregnant or atrophic state which will not usually allow a zygote to implant
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16
Q

How does the mini-pill work?

A
  • norethindrone and levonorgestrel are the synthetic progesterone commonly used
  • taken PO every day except for 7 days in 28 day cycle
  • missing a dose of the pill by hours can lead to ovulation and possible pregnancy
  • risk of contraceptive failure greater than the combination pills
  • there is also an increase risk in ectopic pregnancy (probably because endometrium is not ideal for implantation)
  • 0.5-1.1 pregnancies per 100 women years
17
Q

How do progestin injections work?

A
  • Depo-Provera
  • medroxyprogesterone acetate
  • given IM to buttock or deltoid or as implants
  • 150mg of the depot form of PROVERA (medroxyprogesterone acetate, MPA) every 3 months by deep IM injection given only during the first 5 days after the onset of a normal menstrual period (make sure that person is not pregnant), within 5 days postpartum if not breastfeeding (can begin to have menstrual cycles within a couple of weeks of having the baby so give it within 5 days), or 6 weeks postpartum if breastfeeding (doesn’t decrease milk supply so well-liked for post-partum)
  • risk for iatrogenic cause of dysfunctional uterine bleedings (DUB) is the main problem with injectable progestin-only compounds for birth control
18
Q

Why do progestin-injections present risk for DUB? What other risks are associated with it?

A

Physiology of this based on:

  • estrogens stimulate endometrial growth
  • the generally inhibitory effect of progestins on the endometrium (they stimulate secretion by uterine gland)
  • progestins inhibit release of GnRH, LH, FSH and that decreases production of estrogen
  • stimulates estradiol conversion to estrone (a less potent estrogen)
  • decreases estrogen production by inhibiting pituitary-hypothalamo-gonadal axis
  • endometrium can sluff off
  • 50% of women are amenorrheic after 1 year
  • mean time to pregnancy after cessation is 10 months
  • weight gain but no worse than combination OCs
  • decrease in libido (some people think because of less estrogen)
  • slightly more ectopic pregnancies
19
Q

What are LARCs?

A
  • contraceptive implant
  • IUD (copper or progestin)
  • extremely reliable (0.6-0.05% failure per year)
  • no problems with compliance
  • return of fertility is rapid after removal of device
20
Q

How does the progestin implant work?

A
  • etonogestrel rod; IMPLANON/NEXPLANON
  • made of etonogestrel in a EVA plastic rod
  • one implant is placed in inner side of upper non-dominant arm
  • three years of effective contraception (amount of progestin released decreases steadily after placement)
  • insert between 21-28 days postpartum if not breastfeeding
  • if breastfeeding, insert after the fourth postpartum week and use a second non-hormonal form of contraception for the first week
  • takes time for progestin to get out to be a reliable form of birth control
  • NEXPLANON is a radiopague rod but otherwise identical to IMPLANON which was discontinued in the USA
  • there are no contraceptive implants currently available in Canada but they are likely to be available in a year or so
21
Q

What are warnings with progestin implants?

A
  • insertion/removal requires training
  • purchase of product is limited to trained practitioners
  • subdermal insertion is key to removal otherwise the implant can migrate and cause damage or encapsulate
  • with x-ray they can find the NEXPLANON
  • the implant should always be palpable
22
Q

What are adverse effects of progestin implants (NEXPLANON)?

A
  • irregular menses (DUB)
  • headache
  • vaginitis
  • weight increase
  • acne
  • breast pain
  • abdominal pain
  • pharyngitis
  • there is some indication that women with depressed mood should be carefully observed and implant should be removed with exacerbation of symptoms
23
Q

Describe the new oral progestin LARC being developed

A
  • star shaped device that has progestin in it
  • emerges from a capsule
  • digestible amount of material on the outside so it is taken orally
  • the device expands into the stomach and slowly leak out progestin
24
Q

What is postcoital contraception?

A
  • Morning After Pills (MAPs) or Emergency Contraceptive Pills (EPC)
  • high dose progestin (Plan B):
  • administered within 72 hours of coitus and two pills are taken, one right away and the other within 12 hours
  • it is about 90% effective (instead of a 6-8% chance of becoming pregnant you have a 1% chance)
  • appears to inhibit natural progesterone and estrogen production and ovulation
  • selective progesterone receptor modulator (SPRM):
  • ulipristal acetate blocks the progesterone receptors and thus the effects of progesterone (uterus becomes irritable and endometrium stops being secretory) and inhibits ovulation for a number of days (inhibits LH and FSH surge)
  • an IUD can also be fitted after unprotected intercourse
25
Q

Describe anti-progestins (SPRM)

A
  • Mifepristone (RU 486) antagonizes the effects of progesterone
  • progesterone causes the uterus to be quiescent then antagonism causes the myometrium to become active
  • progesterone is also necessary for maintaining the endometrium
  • combination of both effects usually causes the endometrium to sluff off after 12-72 hours
  • often a prostaglandin (like misoprostol) is given to increase uterine contractions
  • this combination is sold in Canada as Mifegymiso
  • this can be used for abortions up to 8 weeks
  • Ulipristal acetate (Ella) may also be useful for this
26
Q

Combination OCs do not:

a) increase the incidence of DVT
b) inhibit ovulation
c) create thick and scanty cervical mucus
d) increase LH and FSH levels
e) create a hostile endometrium

A

d

27
Q

What is immunocontraception?

A
  • vaccination with zona pellucida peptide produces long-term contraception in female mice
  • also works in elephants
  • begin to make antibodies against zona pellucida
  • any egg that is ovulated will create an immune response
28
Q

What is spermicide/microbicide?

A
  • BufferGel: acidifies semen and maintains protective acidity of vagina
  • ACIDFORM: an acid-buffering and bio-adhesive gel with activity against bacterial vaginosis and Trichomonas vaginalis in vitro
  • these both have spermicidal activity and provide a moderate barrier but should not be considered as birth control
29
Q

Describe the procedure of a vasectomy

A
  • vas deferens comes out lateral to pubic symphysis and goes down to inguinal canal
  • in scrotum, it is close to posterior surface and is accessible surgically
  • make an incision at junction between penis and scrotum and hook out the vas and cut it
  • burn on either side
  • sperm will not be able to make their way to mix with contents of prostate and seminal vesicle (semen deficient of sperm)
30
Q

Describe tubal ligation

A
  • abdomen must be opened
  • uterine tube is ligated
  • major procedure compared to a vasectomy
31
Q

What is an essure?

A
  • inserted into the isthmus of the uterine tube
  • a non-surgical transcervical or hysteroscopic procedure
  • causes an essentially irreversible obstruction in the uterine tube when scars form over the inserts
  • can be surgically reversed but fertility may not be restored and there is a chance of tubal and uterine penetration because of erosion
  • spring expands and work its way through the wall
  • removed from market in 2018
32
Q

How could a male birth control pill work?

A
  • hypothalamus release GnRH to ant pituitary
  • ant pituitary releases LH and FSH which stimulates gonads resulting in gametes
  • sex steroids feedback on the hypothalamus
  • in males if they don’t make testosterone they can no longer sustain an erection and lose interest in intercourse
  • would be a means of chemical sterilization
33
Q

What male contraceptives have been tried?

A
  • heating to inhibit sperm development
  • calcium channel blockers (sperm activation is inhibited) but get lots of side effects
  • gossypol (causes hypokalemia)
  • anything that muddles with excretion of testosterone largely produces the need for contraception because it causes impotence
  • however FSH is largely responsible for sperm production while LH is largely responsible for testosterone production
  • prototype FSH blockers that show some promise but likely testosterone supplementation is required
  • a combination of progestin (inhibits LH and GnRH) and testosterone (inhibits FSH, LH, and GnRH) will likely be approved soon
  • testosterone is needed to replace the drop in testosterone production by the testes