Oral contraceptives Flashcards
Where are oestradiol and progesterone released from?
Ovary
Placenta
Adrenal cortex
Testes
List the three types of oral contraceptives?
Combined preparations
Sequential preparations
Progesterone-only oral preparations (mini-pill)
Which hormones are usually found in oral contraceptives?
Oestrogens: ethinyloestradiol (most are synthetic)
Progestogens: levonorgestrel, cyproterone, drospirenone
Describe the use of cyproterone in oral contraceptives?
New progestogen
Highest venous thromboembolic risk
Antiandrogenic activity (PCOS)
Taken off the market in some countries
Describe the use of drospirenone in oral contraceptives?
Progestogen
Derived from spirinolactone
Antiandrogenic
Describe the mechanism of action of oral contraceptives?
Oestrogen inhibits FSH (maybe LH)
Progestogen can work in some cycles to have negative feedback on LH
Also makes endometrium unfavourable for implantation, mucous inhospitable tio sperm and interferes with coordinated contractions of reproductive system that facilitate conception
Which of the oral contraceptives must be taken at the same time everyday?
Sequential preparations and progestogen-only preparations
Describe the sequential preparation oral contraceptives?
Ratio of doses of oestrogen and progestogen varies to correspond approximately to changes in endogenous levels
Reduces side effects
Describe the use of progestogen-only oral preparations as oral contraceptives?
Used when oestrogens are contraindicated
Least effective
Can be used by lactating women
Why is the progestogen-only oral preparation the only suitable oral contraptive for lactating women?
Oestrogen inhibits lactation
Describe the adverse effects associated with combined oral contraceptives?
Hypertension (small and reversible in healthy individuals)
Venous thromboembolism increased risk
Possible increased risk of breast, cervical and uterine cancer
Other: nausea, vomiting, weight gain etc.
Describe the risk of VTE that is associated with use of COCs?
Increased risk
Associated with dose of oestrogen, the progestogen and presence of other risk factors
Most apparent risk in women over 35 who smoke
Describe the association between COCs and endometrial cancer?
Increased incidence of endometrial carcinoma associated with oestrogen administration
When progestogen given concurrently to woman with intact uterus > protective effect
List the benefits of COCs?
Decreased risk of endometrial cancer
Decreased incidence of ovarian cancer and ovarian cyst formation
Reduction in risk of colorectal cancer
Protective effect on benign breast tumours
Reduction in risk of bone fractures
Reduction in dysmenorrhea and menorrhagia > protection against iron deficieny anaemia
Describe the use of vaginal rings as contraceptives?
Etonogestrel (progestogen) and ethinyloestradiol (oestrogen)
Inserted into vagina for 3 weeks, removed for one week
Low dose (bypasses portal circulation)
