Contraception Flashcards
What types of contraception are being used in the UK?
- sterilisation (28%)
- combined hormonal contraception (25%)
- progesterone only methods: IUD (6%), pill (5%), implants/ injectable (3%)
What are the features of the ideal contraceptive?
- reversible
- effective
- convenient and unrelated to intercourse
- no adverse side-effects
- protective against STIs
- non-contraceptive benefits
- low maintenance and no-ongoing medical input
How do contraceptive clinical trials typically report their failure rates?
By the pearl index or life table analysis
What is the pearl index?
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
What is the life table analysis?
contraceptive failure rate over a specified time-frame
- can provide a cumulative failure rate for any specific length of exposure.
What form does the combined contraceptive come in?
- Pill
- Patch
- Vaginal ring
How effective is the COC?
Over 99% effective = Pearl index 0.3 - 4.0 per HWY
What does the COC contain?
It is an orally active pill combination of 2 hormones
- Ethinyl estradiol (EE)
- Synthetic progesterone (progestogen)
What is the usual dose of the COC?
Usual dose 20 – 35 microgram EE (50 if on liver enzyme inducers)
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How is the CHC usually taken?
- Taken for 21 days and then a pill free week
What is the mode of action for the CHC?
- affects FSH to LH (no surge): inhibits ovulation
- affects cervical mucus: inhibits sperm penetration
- affects endometrium: inhibits implantation
How is a surge of LH and FSH prevented when using the CHC?
Negative feedback of oestrogen and progesterone on the hypothalamus preventing LH and FSH release
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What are the non-contraceptive benefits of the COCP?
- regulates/reduces bleed - helps heavy/painful periods
- stops ovulation - helps pms
- reduction in functional ovarian cysts
- 50% reduction in ovarian and endometrial cancer
- improvement in acne/hirsutism
- reduction in benign breast disease, rheumatoid arthritis, colon cancer and osteoporosis
What are the risks associated with the COCP?
- VTE
- arterial thrombosis - MI/ischaemic stroke (increased further in those with focal migraine)
- breast cancer
- cervical cancer
What is the absolute risk of VTE contraception?
- 5 per 100,000 women years in the general population
- 15 per 100,000 women year with COC use (LNG and NET)
- 25 per 100,000 women years with COC use (GSD and DSG)
- 60 per 100,000 women years with pregnancy
What is the relative risk of VTE with COCP?
Risk increases 3 fold
What are the risk factors for VTE?
- Major surgery and immobility
- Thrombophilias
- 1st degree relative VTE under 45 years
- BMI > 30
What is the effectiveness of the progesterone only pill?
Pearl index of 0.3-3.1 = over 99% effective but it is user dependent.
Why does the POP have lower failure rates in older women?
They are less fertile and perhaps less sexually active.
Give an example of a POP?
Desogestrel pill
How is the desogestrel pill taken.?
- 12 hour window period
- Traditional pills taken within 3 hours of the same time every day without a pill-free interval
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What is the mode of action of POPs?
- nearly all cycles anovulant
- affects cervical mucus - impenetrable by sperm
- most users bleed-free after 4-6 months
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How is DepoProvera given?
1ml deep intramuscular injection into the upper outer quadrant of the buttock every 12 weeks
What is the mode of action for DepoProvera?
- prevents ovulation
- affects cervical mucus - hostile to sperm
- affects endometrium - prevents implantation
What are the advantages of DepProvera?
- Good for forgetful pill takers
- 70% women amenorrhoeic
- Oestrogen-free
What are the disadvantages of DepoProvera?
- Delay in return to fertility - no reduction in fertility
- Reversible reduction in bone density
- Problematic bleeding
- Weight gain
What are the components so the subdermal implant?
CORE
-68mg etonogestrel (ENG) (Progesterone)
MEMBRANE
- Ethinyl vinyl acetate (EVA)
0. 06 mm thick
What is the primary mode of action of the subdermal implant?
Inhibition of ovulation
- 100% women
- Over 3 years of use
- Regardless of weight
What is the secondary mode of action of the subdermal implant?
Effect on cervical mucus
-Inhibiting sperm entry into upper reproductive tract
What is the length of use for long acting reversible contraception?
5-10 years
Why is the copper coil effective against sperm?
Copper is toxic to sperm
What hormone do hormone coils contain?
Progesterone
What is the most effective emergency contraception?
Copper coil
-Can be fitted up to day 19 of a 28 day cycle or up to 5 days after unprotected sex
What emergency contraception can be used within 72 hours of unprotected sex?
Levonorgestrel
What emergency contraception can be used up to 120 hours after unprotected sex?
ulipristal pill (Ella One)
How does emergency contraception compare to ongoing contraception with regards to effectiveness??
Less effective than ongoing contraception
Give an example of a barrier method of contraception.
Condom
What is the failure rate of female sterilisation?
1 in 500
How is female sterilisation carried out?
- Laparoscopic
- Traditional tube ligation using Filshie clips
What is the lifetime risk of laparoscopic tubal occlusion failure rate?
1 in 200
What is a vasectomy?
Permanent division of vas deferens under local anaesthetic
What is the failure rate of vasectomy?
1 in 2,000
What should couples considering sterilisation be informed of?
vasectomy carries a lower failure rate
Why can pain occur with vasectomy?
sperm granuloma (a mass of degenerating spermatozoa surrounded by macrophages)
Why are vasectomies considered irreversible?
Anti-sperm antibodies
What is there no evidence of with vasectomy?
- no effects on testosterone or sexual function
- no increased risk of testicular or prostatic cancer
What is the target for termination of pregnant?
Target is 70% performed before 9 weeks to reduce complications
What are the criteria for induced abortion?
- under 24 weeks
- continuation of the pregnancy involves greater harm to the physical/mental health of the woman and/or
her existing children
What are the indications for induced abortion?
Social reasons
Medical reasons
- Foetal anomaly
- Maternal health
What is home abortion?
- The use of misoprostol at home -
- Safe and endorsed by WHO
What is covered in a clinical consultation for TOP?
- About methods of Termination
- Prolonged bleeding after TOP
- Counselling available after TOP
- Contraception agree & advise
- FBC/Group & Screen/ Rubella/ scan/ Self obtained swab for Chlamydia and gonorrhoea and STI bloods offered
- Certificate A signed
What are the methods fro medical termination of pregnancy?
- Mifepristone switches off pregnancy hormone which is keeping uterus from contracting and allowing pregnancy to grow
- 48 hours later misoprostol initiates uterine contraception which opens cervix and expels pregnancy
What are the possible complications of medical termination of pregnancy?
- Failure < 5 in 100
- Haemorrhage < 5 in 100
- Infection (screen)
- Prolonged bleeding (< 5 in 100)
How does MTOP affect future fertility?
-Unaffected with uncomplicated procedures but can be affected by severe infection, cervical trauma or uterine cavity damage (Ashermans)
What is conscientious objection?
- The right of medical staff to refuse participation in abortion because they have a conscientious objection to the procedure is enshrined within the 1967 Abortion Act
- There is an obligation to ensure that the woman is still able to access abortion care
- Staff have a right to refuse participation as long as this does not affect any duty to participate in treatment which is necessary to save the life or to prevent grave permanent injury to the physical or mental health of a pregnant woman
