Contraception and HRT Flashcards
Define contraception
How is this accomplished?
- the prevention of pregnancy
- this is accomplished by preventing ovulation, preventing fertilisation, or by preventing implantation of the pre-embryo in the uterus, thus preventing the initiation of pregnancy
What are the features of the ideal contracteptive?
100% safe and effective independent of intercourse reversible acceptable, simple and painless cheap independent of medical profession acceptable to every culture, religion and political view used by or obviously visible to women
The ideal contraceptive does not exist so what factors must be taken into account when choosing one?
- patient preferences
- hormonal (age, weight, smoking)
- compliance
- problems related to menstrual cycle (periods, PMS)
- fertility options
How is effectiveness measured in contraceptives?
Measure of failure
- failure rates / 100 woman years of exposure
- PEARL index
- If PEARL INDEX = 4, then of 100 women using the contraception for a year, 4 will be pregnant by the end of the year
What is the average fertility at the following ages in 100 women years?
- no method, young women
- no method, age 40
- no method, age 45
- no method, age 50
- 80-90/100 woman years
- 40-50/100 woman years
- 10-20/100 woman years
- 0-5/100 woman years
What features of human intercourse favour fertility?
- pleasure
- instinct
- drive
- timing (maximal female desire coincides with most fertile phase)
- outpouring of vaginal transudate (raises pH = favourable to sperm)
- orgasm - negative pressure,
What is the fertility window in humans?
5 days before ovulation
and 1 day after
What are the main types of contraception?
Hormonal - CHC, POP, DMPA, implants/injectables
Intrauterine devices - cooper, Mirena
Barrier - condoms, femidom, diaphragm, cap, sponge +/- spermicides
Natural methods - coitus interrupts, fertility awareness
Sterilisation
What are some examples of natural family planning methods?
- rhythm method, avoiding intercourse around ovulation
- Billing’s method, changes in cervical mucus
- Changes in the cervix, high and soft at ovulation
- Basal body temperature
- Coitus interruptus/withdrawal
- Lactational amenorrhoea
What are the advantages and disadvantages of natural family planning?
Advantages - no side effects - in the couple's control Disadvantages - not a very reliable or of contraception - messy and 'clinical'
What are the 3 barrier methods?
condoms male/female
diaphragm and cap
spermicides
- these are reliable if properly used, user dependent
What are the 3 main classes of hormonal contraceptives?
Combined Hormonal Contraceptives
Progesterone Only
Long Acting Reversible Contraceptives
What is the mode of action of CHC’s?
What is their efficacy?
What is their efficacy affected by?
- prevent ovulation via negative feedback on HPG axis
- unfavourable changes to cervical mucus, endometrium, myometrium and fallopian tubes
- 0.2-3/100 woman years
- efficacy affected by enzyme inducers, diarrhoea, vomiting
What are the benefits, side effects and disadvantages of CHC?
Benefits
- highly effective, convenient, reversible
- bleeding/anaemia, dusmenorrhea, prevents ovarian cysts, reduces risk of ovarian and endometrial carcinoma
Side effects
- headaches, weight gain, breast tenderness, bloatedness. leg cramps, post pill amenorrhea
Disadvantages
- small increase in breast cancer risk
- circulatory disease
- venous thromboembolic, and arterial wall disease
What are the Evra patch and NUVA ring
Evra patch - transdermal CHC - once weekly - more than 99% effective - bypasses 1st pass metabolism NUVA ring - vaginal ring CHC - in situ for 21 days, removed for 7 days and new ring inserted - 98% effective
What is the mode of action of the POP?
What is its efficacy?
Changes in cervical mucus
Anovulation
Changes in endometrium
- 0.3-4/100 woman years