contraception P2 Flashcards
ThePearl Index
defined as the number of contraceptive failures per 100 women-years of exposure. It looks at the total months or cycles of exposure from the initiation of the product to the end of the study
Life Table Analysis
provides the contraceptive failure rate over a specified time-frame and can provide a cumulative failure rate for any specific length of exposure.
L.A.R.C. method failure
pregnancy despite correct use of method by user
L.A.R.C. user failure
pregnancy because method not used correctly by user
When can sex cause pregnancy ?
If / 26-32 day cycle and not on hormonal Rx
Likely ovulate day 12-18 ( 14 days before period)
Egg survives approx 24 hours
Most sperm survive less than 4 days ( 5% may survive 7 days)
SO highest chance of pregnancy is from sex on day 8-19
L.A.R.C. options
Combination of 2 hormones
ethinyl estradiol (EE) and synthetic progestogen
Stop ovulation, also affect cervical mucus and endometrium
Standard regime 21 days use then a hormone free week
Tailored regimes e.g 21 days -4 day break, tricycling 63 days use, 4-7 day break/ continuous use - no need for uncomfortable inconvenient withdrawal bleed, avoids forgetting to restart after break
Pill taken daily ( anytime in 24 hrs-)
not good if frequent GI upset
Patch EVRA TM changed weekly- < 5% have skin reaction
Ring Nuvaring TM changed every 3 weeks
(can take out for 3 hrs in 24 so may prefer to take out for sex)
Combined hormonal methods Non-contraceptive benefits
Regulate/reduce bleeding- help heavy or painful natural periods
Stop ovulation- may help premenstrual syndrome
Reduction in functional ovarian cysts
50% reduction in ovarian and endometrial cancer
Improve acne / hirsutism
Reduction in benign breast disease, rheumatoid arthritis, colon cancer and osteoporosis
Combined Hormonal Methods Troublesome Side effects
Breast tenderness
Nausea
Headache
Irregular bleeding first 3 months
Mood ? Causal or other life events
Weight gain- not causal
Combined Hormonal Methods -Serious Risks
Increased risk venous thrombosis- DVT PE
Avoid if BMI >34, previous VTE, 1st degree relative VTE under 45, reduced mobility, thrombophilia eg systemic lupus erythematosus
Increased risk arterial thrombosis- MI / ischaemic stroke
Avoid in smokers >35, personal history arterial thrombosis, focal migraine, age>50, hypertension>140/90
Avoid if active gall bladder disease or previous liver tumour
Increased risk cervical cancer- but data predates HPV vaccine
Increased risk breast cancer- back to normal after 10 years off Rx
Avoid if previous breast cancer
NB non BRCA family history of breast cancer not a contraindication
No overall increased cancer risk for CHC users
Risk of venous thromboembolism (VTE)
In absolute terms the risk of VTE increases from:
2 per 10,000 women per year in the general population
5-7 per 10,000 women per year with COC use (LNG and NET progestogen)
6-12 per 10,000 women years with patch/ ring/ COC other progestogen use )
50 per 10,000 women years with pregnancy
In relative terms the risk increases three-fold which sounds alarming
Need VTE prophylaxis if inpatient/ surgery/immobile
Progestogen-only pill (POP) ‘ mini-pill’
Take at the same time every day without a pill-free interval
Not good choice if frequent GI upset
Desogestrel pill – 12 hour window period
Nearly all cycles anovulant- also affect mucus.
Most users are bleed free after first 4-6 months.
Traditional LNG NET pills- 3 hour window period 1/3 anovulant 2/3 rely on cervical mucus effect
1/3 bleed free, 1/3 irregular, 1/3 regular periods
Oestrogen free- so very few contraindications
-Personal Hx Breast cancer / liver tumour
Progestogenic side effects
Troublesome not ‘dangerous’ very variable between individuals
Appetite increase
Hair loss/gain
Mood change
Bloating or fluid retention
Headache
Acne
No increased risk venous or arterial thrombosis with contraceptive dose progestogens
Avoid if current breast cancer or liver tumour past/present
Injectable Progestogen ‘The jag’
medroxyprogesterone acetate dose every 13 weeks
1ml deep intramuscular injection into the upper outer quadrant of the buttock Depoprovera TM
0.6ml subcutaneous injection abdomen/thigh
possible self administration Sayana pressTM
- prevents ovulation
- It alters cervical mucus making it hostile to sperm
- Makes endometrium unsuitable for implantation
Injectable Progestogen benefits
Only need to remember every 12-14 weeks
70% women amenorrhoeic after 3 doses
Estrogen-free so few contraindications
injectable progesterone risks
Delay in return to fertility – average 9 months
Reversible reduction in bone density- discuss her other risks for osteoporosis
Problematic bleeding especially first 2 doses
Weight gain 2/3 women gain 2-3 kg
This is the only contraceptive method with a causal effect on:
weight gain , delayed return of fertility and bone density
