Combined oral contraceptive pill (COCP) Flashcards
What is contained in COCP?
Contains a combination of oestrogen and progesterone
Effectiveness of COCP?
More than 99% effective with perfect use, but less effective with typical use (91%).
What age is COCP licensed for use up to?
50 years of age
What are the 3 main mechanisms that COCP prevents pregnancy?
Preventing ovulation (this is the primary mechanism of action)
Progesterone thickens the cervical mucus
Progesterone inhibits proliferation of the endometrium, reducing the chance of successful implantation
How does preventing ovulation stop pregnancy from occurring?
Oestrogen and progesterone have a negative feedback effect on the hypothalamus and anterior pituitary, suppressing the release of GnRH, LH and FSH.
Without the effects of LH and FSH, ovulation does not occur. Pregnancy cannot happen without ovulation.
So increase in oestrogen and progesterone = decrease in GnRH, LH and FSH, inhibiting ovulation leading to NO PREGNANCY.
Most common COCP regimes?
21 days on and 7 days off
63 days on (three packs) and 7 days off (“tricycling“)
Continuous use without a pill-free period
Risks and side-effects of COCP?
Unscheduled bleeding is common in the first three months and should then settle with time
Breast pain and tenderness
Mood changes and depression
Headaches
Hypertension
Venous thromboembolism (the risk is much lower for the pill than pregnancy)
Small increased risk of breast and cervical cancer, returning to normal ten years after stopping
Small increased risk of myocardial
infarction and stroke
Is risk of VTE (venous thromboembolism) higher in pregnancy or when on the COCP?
VTE risk is in pregnancy.
Pregnancy is a hypercoagulable state meaning that risk of blood clot is higher.
What are the benefits of COCP use?
Effective contraception
Rapid return of fertility after stopping
Improvement in premenstrual symptoms, menorrhagia (heavy periods) and dysmenorrhoea (painful periods)
Reduced risk of endometrial, ovarian and colon cancer
Reduced risk of benign ovarian cysts
Can improve other issues I.e. acne
What are contraindications for the COCP?
In these cases COCP is UKMEC 4 (do not use due to high risks):
- Uncontrolled hypertension (particularly ≥160 / ≥100)
- Migraine with aura (risk of stroke)
- History of VTE
- Aged over 35 and smoking more than 15 cigarettes per day
- Major surgery with prolonged immobility
- Vascular disease or stroke
- Ischaemic heart disease,
cardiomyopathy or atrial fibrillation - Liver cirrhosis and liver tumours
- Systemic lupus erythematosus (SLE) and antiphospholipid syndrome
What is a UKMEC 3 (risk outweighs benefit) factor for COCP?
BMI over 35
When is COCP usually started in cycle and why?
Usually started on first day of cycle (first day of menstrual cycle).
Usually offers immediate protection.
What are things that should be checked when prescribing COCP?
Different contraceptive options, including long-acting reversible contraception (LARC)
Contraindications
Adverse effects
Instructions for taking the pill, including missed pills
Factors that will impact the efficacy (e.g. diarrhoea and vomiting)
Sexually transmitted infections (this pill is not protective)
Safeguarding concerns (particularly in those under 16)
How are contraindications screened for COCP?
By discussing and documenting:
- Age
- Weight and height (BMI)
- Blood pressure
- Smoker or non-smoker
- Past medical history (particularly migraine, VTE, cancer, cardiovascular disease and SLE)
- Family history (particularly VTE and breast cancer)
What is regarded as missing the COCP?
Missing one pill is when the pill is more than 24 hours late (48 hours since the last pill was taken).
