combined hormonal contraception Flashcards
what is the mechanism of action of combined hormonal contraception?
act primarily to inhibit ovulation due to the negative feedback effect of the oestrogen and progesterone on the hypothalamo-pituitary axis.
This prevents the surge in LH thus preventing ovulation.
The progesterone also acts to inhibit proliferation of the endometrium, creating unfavourable conditions for implantation and increases the thickness of cervical mucus, preventing passage of sperm.
The period free of hormones, (pill-free break or taking placebos) causes a fall in hormonal concentration which leads to degeneration of the endometrium and menstrual bleeding.
what are the types of COCP?
Monophasic pills: every pill contains the same levels of oestrogen and progesterone.
Phasic pills: the level of oestrogen and progesterone in the pills changes throughout the cycle.
Oral contraceptives come in packets of 21 or 28 tablets. Packets of 21 are taken consecutively for 21 days and then a 7 day break between packets where no pills are taken. The packets of 28 are taken consecutively for 28 days and there is no break before starting the next packet
what is the contraceptive patch?
a small 5cmx5cm patch that can be stuck onto the upper arm, abdomen, buttock or back to prevent pregnancy.
hormones work in the same way as the COCP by preventing ovulation, thinning the endometrial lining and thickening cervical mucus.
The patch is applied and changed every 7 days over a period of 3 weeks (21 days in total) and then the patch is removed for 7 patch-free days where the individual will usually experience a withdrawal bleed.
The patch is extremely sticky and can be used whilst bathing and swimming.
may cause skin irritation and may be seen
what is the contraceptive vaginal ring?
a plastic ring placed into the vagina
hormones work in the same way as the COCP by preventing ovulation, thinning the endometrial lining and thickening cervical mucus.
Once inserted the ring sits in the vagina for 21 days. It is then removed for 7 days before inserting the new ring.
however, patient must be comfortable inserting and removing it
what are the advantages of using combined hormonal contraceptives?
Non invasive
More effective than barrier methods if taken correctly
Sex doesn’t need to be interrupted to use contraception
Menses tends to become regular, lighter and less painful, also allowing for control over timing of menses
Reduced risk of cancer of the ovary, uterus and colon
Reduced risk of functional ovarian cysts
Normal fertility returns immediately after stopping usage
what are the disadvantages of using combined hormonal contraceptives?
User dependent
Some temporary adverse effects such as headaches, breast tenderness and mood changes can be experienced by some women
Blood pressure may increase
Women may experience breakthrough bleeding and spotting for the first few months
Increased risk of venous thromboembolism
Small increase in risk of myocardial infarctions and strokes
Small increase risk of breast and cervical cancer
what are the contraindications?
BMI >35
Breast feeding
Smoking over the age of 35
Hypertension
History of or family history of venous thromboembolisms
Prolonged immobility due to surgery or disability
Diabetes mellitus with complications e.g. retinopathy
History of migraines with aura
Breast cancer or primary liver tumours
what is the perfect use and typical use effectiveness of COC methods?
perfect = 99%
typical = 91%
Why is migraine with aura a complete contraindication of the COCP?
increased risk of stroke
migraines with aura or >72hrs is a contraindication
migraines without aura scores more a category 3 in the UK MEC
what is migraine with aura?
Migraine with aura (also called classic migraine) is a recurring headache that strikes after or at the same time as sensory disturbances called aura. These disturbances can include flashes of light, blind spots and other vision changes or tingling in your hand or face
