Contraception Flashcards
Describe the population trend in Canada between 1959 and 2023?
The birth rate in Canada decreased from 116 births per 1000 in 1959 to 10.1 births per 1000 in 2023 (10 fold decrease)
What is the average maternal age at first birth?
30 years old
How does the birth rate in Saskatchewan compare to the national average in 2022?
In 2022, the birth rate in Saskatchewan was 11.9 births per 1000, slightly higher than the national average of 10.1 births per 1000.
What percentage of pregnancies are unplanned?
40-60%
What percentage of unintended pregnancies end in abortion?
50%
Approximately how many individuals have had at least one induced abortion?
1/3 of individuals
What are the four main hormones related to the menstrual cycle?
- FSH
- LH
- Estrogen
- Progesterone
What is the function of GnRH (gonadotropin releasing homone) in menstruation?
GnRH stimulates the pituitary gland to release FSH and LH.
What is the function of FSH in the menstrual cycle?
FSH stimulates the maturation of follicles in the ovaries.
What is the function of estrogen in the menstrual cycle?
Estrogen, predominantly estradiol, stimulates the thickening of the endometrium and suppresses FSH through negative feedback.
What is the function of LH in the menstrual cycle?
LH triggers ovulation 28-32 hours after its levels surge
Describe the role of progesterone in the menstrual cycle
Progesterone, produced by the corpus luteum prepares the endometrium for implantation and signals the hypothalamus and pituitary to stop FSH and LH production through negative feedback.
What is the significance of the corpus luteum in relation to hormones associated with the menstrual cycle?
The corpus luteum produces androgens, estrogen, and progesterone during the luteal phase of the menstrual cycle.
If implantation does not occur, it stops producing progesterone (reducing negative feedback for FSH and LH, resulting in shedding of endometrium lining and menstruation)
What are the two phases of the menstrual cycle?
- Follicular phase (egg development in ovary)
- Luteal phase (egg has left ovary)
How long is the menstrual cycle?
A plurality of menstrual cycles are 28 days long (14 days follicular, 14 days luteal)
Some women may have longer or shorter total cycle, but luteal phase always lasts 14 days the difference is in the follicular phase
Describe the follicular phase of the menstrual cycle
The follicular phase is the first phase of the menstrual cycle, starting from the first day of the period.
- During this phase, a follicle grows and develops (due to the effects of FSH), with one follicle becoming dominant.
- The dominant follicle produces estrogen, which stops menstrual flow and stimulates the thickening of the endometrial lining.
-Additionally, it leads to the production of thin, watery cervical mucus
Describe the luteal phase of the menstrual cycle
The luteal phase is the second half of the menstrual cycle, lasting for approximately 14 days. During this phase, the released ovum travels through the fallopian tubes to the uterus.
What are the different types of contraception?
- Hormonal
- Barrier
- Permanent
- Natural family planning
What are the two main hormones used in hormonal contraceptives?
Estrogen (ethinyl estradiol or estetrol)
Progestins (synthetic hormones that activate progesterone receptors)
What is the mechanism of action for combined hormonal contraceptives?
Combined hormonal contraceptives usually combine ethinyl estradiol and progestins
Estrogen supresses release of FSH (stops ovulation and maturation of eggs in the ovary)
Progestins
- Supress release of LH and FSH (inhibits ovulation)
- Thickens cervical mucus (impedes sperm transport)
- Changes in endometrial lining (not hospitable to implantation)
What are the main three categories of hormonal contraceptives?
- Combined (estrogen + progestin)
- Progestin-only
- Long-acting reversible contraception
What are some types of combined hormonal contraceptives?
- Pill
- Patch
- Ring
What are some types of progestin-only hormonal contraceptives?
- Pill
- Injection
What are some types of long-acting reversible contraception?
- IUS/IUD
- Implant
What is the most common dosing regimen for birth control pills?
They try to mimic the natural menstrual cycle of 28 days. There is often 21 days of hormones and 7 days of placebo pills
What are the differences between three phasic formulations for hormonal contraception?
Monophasic (fixed levels of EE and progestin)
Biphasic (fixed EE levels and increased progestin in 2nd phase)
Triphasic (fixed or variable EE, but increases in all 3 phases)
What are the advantages of continuous hormonal therapy?
- Continuous dosing regimens are more forgiving for missed doses
- May increase effectiveness by reducing time in hormone-free interval
- Reduce the number of periods
How should a contraceptive pill be started?
Most effetcive on Day 1 (first day of period) and taken daily at the same time
If the patient is not starting on Day 1, then use back-up birth control for first 7 days
What is the birth control failure rate for combined pills in the real world?
3-8% (forgetting to take pill, taking pill late)
Why is missing a dose in Week 1 more serious vs. Week 2 or 3?
This is because missing a dose in Week 1 is close to the time when ovulation occurs, in the event that estrogen and progesterone activity was low due to missed dose, unintended ovulation can occur
What should women patients do when they have missed a dose of their birth control pill?
Consider emergency contraceptive, especially in Week 1
The severity of missing a dose is greatest in Week 1, and tapers off in Week 2 and 3
What are the most common side effects associated with starting combined birth control pills?
Breakthrough bleeding (largely due to estrogen component in it only lasts 1-10 days)
- Check for adherence
Breast tenderness
- If lasts longer than the first 3 months, look for other causes
- Change to pill with lower estrogen
Nausea
- Take HS or with food
- Change to pill with lower estrogen
What are some side effects seen with combined birth control that are normally not seen in trials, but seen in practice?
Weight gain
Headache
Mood changes (depression)
Acne
What are the benefits of combined hormonal contraception?
- Simple and effective birth control
- Improve menstrual symptoms and regularity
- Decreases incidences of many woman-specific conditions (endometriosis, ovarian cancer, osteoporosis)
What are the risks of combined hormonal contraceptives?
- Treatment failure (especially if the patient is on 20mcg and missed dose)
- Venous thromboembolism (risk is 2-3x times higher risk, largely due to estrogen, but lower risk for VTE if pregnant)
- MI and stroke (arterial thrombosis)
Which patient profiles that use hormonal contraceptives are especially at risk for blood clots?
Patients who smoke and are over 35 should not use combined hormonal contraceptives (estrogen is responsible for increasing clot risk)
What are some contraindications for combined hormonal contraceptives?
Estrogen is the cause for most contraindications
- Thromboembolic disease
- Ischemic heart disease/stroke
- Known or suspected breast cancer
- Migraine with aura
- Post-partum (wait at least 3-6 weeks bc woman already has a high natural dose of estrogen following birth), can increase VTE risk
What hormones are found in transdermal contraception?
erhinyl estradiol and progestin
When should transdermal contraception be started?
Apply patch on Day 1, if not Day 1 use back-up contraception or avoid sex for 7 days
How should a transdermal contraception patch be applied?
1 patch applied once per week x 3 weeks (rotate site), then no patch for 1 week (HFI)
The patch can be applied to upper arm, buttocks, lower abdomen, upper torso
What are some adverse effects to transdermal contraception?
- Similar to oral hormone contraception
- Local irritation
- Increased spotting i first 2 cycles
- Less effective in patients over 90kg and increased clot risk
What is the brand name for intravaginal contraception?
Nuvarings are a popular choice
How are intravaginal contrecptives inserted?
- Insert anywhere in the vagina between days 1-5 (use backup birth control for 7 days if not started on Day 1)
- Leave in for 3 weeks, remove for 1 week