Contraception Flashcards
(123 cards)
How many pregnancies are unplanned?
40 - 60% of pregnancies are unplanned
How many unintended preganncies end in abortion?
50% of unintended pregnancies end in abortion
Abortion Rates
Approximately 1/3 of individuals have had at least one induced abortion
What are the two phases of the menstrual cycle? When do they start?
FOllicular Phase
Luteal Phase
The follicular phase is from the start of menstruation to the moment of ovulation. The luteal phase is from the moment of ovulation to the start of menstruation (the final 14 days of the cycle).
How long is the luteal phase?
Always 14 days long –> 14 days from the start of menstruation
Describe the menstrual cycle
- Hypothalamus release Gonadotropin releasing hormone which causes anterior pituitary to release FSH and LH
- Days 1-4: Increase FSH. FSH stimulates 15-20 primordial follicles in the ovary to start dveloping. As they develop, granulosa cells surrounding them secrete estrogen.
Days 5-7 - One follicle dominant
- Estrogen causes negative feedback onto the anterior pituatary and hypothalamus. As estrogen rises, LH and FSH release are supressed. Stops menstrual flow
Stimulates thickening of endometrial lining
↑ production of thin, watery cervical mucus - Prior to ovulation, estrogen levels drop as follicle is getting to release the ovum. There is a spike in LH that causes the follicles to reach the surface of the ovary and release the ovum. Consistently high estrogen levels stimulate the pituitary to release a mid-cycle surge of LH.
- Luteal Phase. Follicle that released ovum collapses and becomes corpus luteum. The corpus luteum secretes high levels of progesterone and little estrogen and androgens. Progesterone maintains negative feeddback to stop LH and FSH production.
- If ovum fertilized occurs, fetus secretes HCG (human chorionic gonadotrophin) to keep corteus luteum alive.
- If not fertilized, corpeus luteum degenerates and stops producing estrogen and progesterone. This drop removes negative feedback to hypothalamus and pituatary and levels of FSH levels rise again and cycle is restarted (release GnrH). Also, triggers endometrium to break down and mentsrutaion occurs.
What is the main job of FSH and LH?
FSH - Stimulates dvelopment of follicles
LH- Causes ovulation
What is estrogen?
Sex steroid hormone that acts on estrogen receptors to promote female secondary sexual charcteristics
- Develop the breast tissue, vulva, vagina and uterus around puberty
- Development of endometrium
- Cause mucous in cervix to thin so sperm can penetrate it around the time of ovulation
What is progesterone?
Steroid sex hormone
- Produced by corpus luteum after ovulation
- If preganancy occurs, the placenta takes over production of progesterone around 5-10 weeks of preganncy
What does progesterone do?
- Act on same tissues as previously acted on by estrogen:
i) Thickening and maintain endometrium
ii) Thicken cervical mucous
iii) Cause slight increase in body temp
What is menstruation?
Starts on Day 1 of cycle
- Superficial and middle layers of endometrium seperate from basal layer of endometrium
- Tissue broken down in uterus and released through cervix and vagina
- FLuid containing blood released from vagina and lasts 1 to 8 days
Main role of GnRH
Stimulates pituitary to release FSH and LH
MAin role of FSH
Stimulates maturation of follicles in ovaries
Main role of estrogen
Stimulates thickening of the endometrium (uterine lining)
Suppresses FSH (negative feedback)
Signals LH
Main role of LH
Triggers ovulation
Main role of progesterone
Produced by the corpus luteum (mass of cells resulting from the ruptured follicle when the ovum is released)
Makes the endometrium favourable for implantation
Signals the hypothalamus and pituitary to stop FSH and LH production (negative feedback)
How long is an average menstrual cycle?
Average cycle is 28 days (range 21-40 days)
What is day 1 of the cycle?
Day 1 of cycle = first day of period (menses)
Describe hormone changes in menstrual cycle
When does ovulation occur?
28-32 hours after LH surge
What are the methods of contraception?
Hormonal
Barrier
Permanent
Natural family planning
What are the componenets of hormonal contracpetions?
Estrogen:
Ethinyl estradiol (EE)
–> Synthetic form of estradiol
–> Most common form
Estetrol (approved in Canada in 2021)
–> Plant source
Progestins (NOT progesterone; synthetic form that acts on estrogen receptors)
Numerous options:
–> Synthetic hormones that activate progesterone receptors
Structurally similar to testosterone
–> Androgenic effects (acne, oily skin, hirsutism)
Anti-androgenic:
–> Cyproterone acetate –> Diane-35 –> used for acne in Canada –> works as birth control, but not indicated in Canada
–> Drosperinone
MOA of Hormonal COntraceptions.What does each hormonal drug do?
Estrogen and progestin provide negative feedback which inhibits ovulation
Estrogen:
Suppresses release of FSH
Progestin:
Suppresses release of LH and FSH
Thickens cervical mucus (impedes sperm transport)
Changes endometrial lining (not hospitable to implantation)
How can hormonal contraception be delivered?
Oral (the Pill)
Injectable
Transdermal
Intravaginal
Intrauterine (hormonal and non-hormonal options)
Implantable