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
2
Q
What are contragestational agents?
A
- keep gestation from occuring
- work to keep fertilized egg/zygote from implanting
- IUD, morning after pill
3
Q
What are abortifacients?
A
- cause the termination of an established pregnancy
- mifepristone, mechanical means of abortion
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)
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
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)
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
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
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)
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
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
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
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
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
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
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
