Contraception Flashcards
How are contraceptives broadly categorised?
Preferred method is life table failure probabilities.
Some methods have no difference between typical and perfect use failure rates and those that have large differences. There are also different likelihoods of discontinuation for different methods.
Long Acting Reversible Contraception (LARC): all require administration <1 per cycle: injectable, subdermal implant, copper IUD, progestogen-only intrauterine system (IUS).
Reversible: require action around time of sex: abstinence, male and female condoms, diaphragms, caps, sponges
Require regular action: POPs, COCPs, combined transdermal patch, combined vaginal ring, fertility awareness. NB: withdrawal and spermicide alone are not deemed effective methods of contraception in the UK.
Permanent: vasectomy (reversal can be attempted), tubal occlusion with clips/rings (usually via laproscopy); reversal can be attempted. Tubal occlusion via hysteroscope, reversal cannot be attempted.
Barrier methods: condoms, caps and diaphragms work by acting as a mechanical barrier to sperm (men – condoms, women – condoms diaphragms and caps). Condoms do not require additional spermicide. Generally recommended that spermicide is used with diaphragms and caps.
How does combined hormonal contraception act?
- Ovarian suppression: decreased GnRH pulsatility in hypothalamus > decreased pituitary responsiveness to GnRH stimulation > suppression of LH + FSH production > inhibition of mid-cycle LH surge
- Thickening the cervical mucus to prevent sperm entry into upper genital tract
- Endometrial effect also doubtless occurs but contribution to the contraceptive effect has never been substantiated.
How does progestogen only contraception act?
- Thickening of cervical mucus and a decrease in its amount (increased visoscity)
- Ovulation suppression: prevention of LH surge - FSH + oestrogen remain in normal range
- Endometrial alterations which may inhibit implantation (decrease in thickness)
Injectables suppress ovulation in all women (main mechanism of action). The POP may or may not suppress ovulation so main mode of action is on mucus (but the desogestrel POP suppresses ovulation in about 97% of cycles). The implant suppresses ovulation, but this is not absolute, especially towards the end of the 3 years.
How does progestogen only EMERGENCY contraception act?
Levonelle contains Levonorgestrel (3 days) or EllaOne contains UPA (5 days)
Follicular development arrested / delayed > LH surge blocked / delayed / blunted. No effect on sperm migration or tubal transport has been demonstrated.
There is no discernible effect on endometrial development. This means that progestogen-only emergency contraception in the luteal phase of the cycle may be less effective.
The progesterone receptor modulator (PRM) ulipristal acetate is now also available as emergency contraception (EllaOne). PRMs block receptors in the ovary, inhibit the LH surge and have a powerful endometrial inhibitory effect. The endometrial effect is probably not a significant mechanism of action at the low dose of ulipristal acetate used for emergency contraception.
How does the IUS act?
Profound effect on the endometrium and cervical mucus. The foreign body effect is much less important than with the IUD.
Endometrial proliferation is inhibited; the endometrium becomes thin + atrophic which makes it impossible for implantation. Cervical mucus becomes thickened and impenetrable to sperm. Although ovulation not usually inhibited, follicular diameter is reduced + the normal increased secretion of progesterone from the corpus luteum in the luteal phase (second half) of the menstrual cycle is reduced in some individuals.
How does the IUD act?
Foreign body reaction with increased prostaglandin production and leucocyte infiltration within the endometrium. The copper also affects endometrial enzymes, glycogen metabolism + oestrogen uptake. Copper has a direct toxic effect on sperm & ova.
Effect on endometrium as is apparent as sperm phagocytosis + interference with sperm transfer and implantation.
Prevention of fertilisation is considered to be the primary mode of action of IUDs when used as regular contraception. Prevention of implantation is a back-up mechanism in use a regular method of contraception, but is likely to be a more important mechanism in use as emergency contraception.
Primary effect through copper ions: direct effect on sperm and ova, decreased sperm motility and survival. Secondary effect on endometrium: sperm phagocytosis and impeded implantation.
Summarise how the IUD and IUS act differently?
IUD prevents fertilisation, IUS does not
IUS suppresses endometrium and thickens mucus, IUD does not.
BOTH will create a foreign body response and prevent implantation.
Outline whether the following primarily act on ovulation, cervix or endometrium
COCP POP Injection Subdermal implant IUS
COCP - ovulation POP - cervix Injection - ovulation Subdermal implant - ovulation IUS - endometrium
Efficacy vs effectiveness?
Efficacy: how well a method works in phase 3 trials. Subjects in the trials are not representative of the general population + daily calendar recording, which is mandatory in trials + enhances adherence.
Effectiveness: how well a method works in real life, effectiveness is dependent on using the method according to the instructions and not abandoning the method.
What is UKMEC?
Assessment of Risk & Medical Eligibility for Contraceptives - not to be substituted for clinical judgement + does not provide guidance on multiple comorbidities
UKMEC 1: condition with no restriction for use of method
UKMEC2: advantages of method outweigh theoretical or proven risk
UKMEC3: theoretical or proven risks usually outweigh advantages – can be used but may require expert clinical judgement and/or referral to specialist contraceptive provider, since use of method not usually recommended unless other methods not available or acceptable.
UKMEC4: condition which represents an unacceptable health risk if the method were to be used.
In general 2 or more category 2s does not necessarily make a 3, but two or more category 3s is likely to make a 4.
What might cause the UKMEC category to vary for a certain condition?
For a particular method, category may differ depending on:
- Whether woman is starting a method of contraception when she already has a specific medical condition (initiation)
- Whether she is continuing to use a method and develops a condition (continuation)
For example, if a woman has an MI while taking the POP (continuation) this is regarded as UKMEC3. If woman has had MI in past (initiation) wishes to start POP – UKMEC2.
Duration of use particularly relevant when assessing safe continuation. e.g. if POP is used for many years and symptoms are of recent onset, continuation is unlikely to be a problem, whilst recent initiation and recent symptom onset may make continuation less safe.
History taking before deciding on contraceptive method? / exams?
- Vascular: headache especially migraine, veins: varicose, phlebitis, thrombosis, heart disease: ischaemic, valvular, congenital, stroke, hyperlipidaemia, venous thromboembolism: especially if on anticoagulants
- Medical conditions: epilepsy, liver/gall bladder disease, autoimmune diseases, bowel disorders, diabetes, cancer (especially breast, ovarian, endometrial)
- Lifestyle: smoking status, partner(s) in <12 months, sexual activity, contraceptive history: previous use and experience of methods
- Other medical history: mental health, especially depression, medication, allergies, including latex, immobility, STIs / HIV / PID, FHx: MI, CV incident, VTE and breast/ovarian cancer in 1st degree relatives, last menstrual period, unexplained vaginal bleeding, obstetric history (deliveries, caesareans, miscarriages, abortions, ectopics), postpartum (breast feeding or not), post-abortion, gynae problems: severe dysmenorrhoea, endometriosis (fibroids, toxic shock syndrome), GTD, CIN
BP management only relevant for oestrogen containing products.
Weight & height relevant for oestrogen and a baseline for those initiating hormonal products who may gain weight or perceive weight gain / bloating.
Pelvic examination must only be performed when strictly necessary. IUD/IUS/female barrier/combined vaginal ring: pelvic examination. General principle is that exams must be relevant to method – lab investigations rarely needed (waste resources). Over-medicalisation of contraceptive consultation can be off-putting for women (especially young)- can become barrier to access.
Combined hormonal: BP at 3 month review, BMI at baseline, annual check BP and BMI.
Urine, blood testing and breast exam are not indicated / not evidence based.
Migraine with aura - UK MEC?
COCP UKMEC4 – risk of ischaemic stroke in pill takers without aura has no increased risk or 3x increased risk.
Migraine with aura risk ranges from 2x increase to 9x increase in different studies.
Progestogen only method is UKMEC2.
Combined vaginal ring and combined transdermal patch are UKMEC4 (oestrogen).
How to differentiate migraine with aura from other headaches?
Positive response to recent unilateral headaches associated with nausea photophobia and malaise in otherwise well person suggests migraine
Headache in migraine typically throbbing, whereas tension headache usually described as pressure or muscle tightness
Migraine: premonitory phase (craving / tiredness / heightened perception / fluid retention) may or may not be followed by aura. Aura lasts <1 hour then headache starts.
Migraine with aura is less common than migraine without aura. Most auras = bright homonymous scotoma which gradually enlarges from a small spot into a C-shape. Sensory symptoms are less common than visual symptoms in aura - generally consists of pins and needles spreading up the arm and into face. Speech disturbance is rare
V important to distinguish aura symptoms from not aura - generalised flashing lights or blurred vision and photophobia are not part of aura
BMI UKMEC?
Obesity is risk factor for combined hormonal contraception (CHC). Care must be taken when making clinical judgements about BMI – pregnancy has higher risk of VTE than taking CHC!
30-34 = UKMEC2 35 = UKMEC3
3 types of COCP?
- Monophasic COCP (most widely used): 21 identical daily tablets, followed by 7 pill free days (withdrawal bleed)
- Phasic COCP : diff hormone strengths taken in order mimicking hormonal fluctuations of a normal cycle – withdrawal bleed usually occurs in pill free interval (PFI)
- Every day COCP: placebo pills taken instead of PFI
Non-contraceptive benefits of the COCP?
- Regulate menstruation and decrease blood loss
- Reduce risk of benign ovarian cysts and functional ovarian tumours (related to duration of use)
- Raises sex hormone binding globulin (SHBG) levels and suppresses ovarian androgen production – may lead to reduction in hirsutism, acne and seborrhoea with maximum benefit after 3-6 months.
- Reduction in risk: ovarian cancer 50% cumulative over 15 years, endometrial cancer 0.5 RR, colorectal cancer 0.82 RR
- Endometriosis: drug of choice for symptoms of endometriosis – safe and economical alternative to surgery
COCP and VTE?
Increases risk
But pregnancy is higher risk
Increased by smoking, obesity and postpartum
COCP and ischaemic heart disease?
May be very small increased risk, this risk increases with smoking and hypertension
UKMEC3 - adequately controlled HTN, BP 140-159/90-99, smoking <15/day and age >35, stopped smoking <1 year and age >35
UKMEC4 - >160 / 100, vascular disease, smokes >15/day and age >35
COCP and breast cancer?
Advise women that if there is an increased risk of breast cancer it is likely to be very small and to return to background risk ten years after stopping
UKMEC3 - remission and no recurrence last 5 years, carrier of mutation associated with breast cancer e.g. BRCA1, past history of breast cancer
UKMEC 4 - current breast cancer
