Oral Contraceptive Flashcards
Why are synthetic progesterones & oestrogen’s used?
Natural progesterones are broken down when taken orally
Oestrodial is also rapidly broken down, therefore need synthetic ones
What is ethinyloestradiol?
Most common synthetic oestrogen used
Used in vaginal ring
What are three common synthetic progesterones?
Cyproterone
Levonogestrel
Drospirenone
What are some uses of levonogestrel?
What are of its adverse effects?
Oldest, cheapest progesterone used
Used in OCP, intrauterine device, hormone replacement therapy and emergency contraceptive
Androgenic effects - hirutism
What are the uses of cyproterone & drospirenone?
What are some benefits?
What are some limitations?
Both are synthetic progesterones used in the OCP for heavy bleeding, painful periods & in combination with spiraloactone for PCOS
Anti-androgenic - don’t have hirutism side effects
Newer, more expensive
Some anti-mineralocorticoid activity (aldosterone receptor antagonist) - mild diuretic effect
Associated with increased thrombosis risk (especially cyproterone)
What are the 3 types of ORAL contraceptives?
List in order of effectiveness
Combined oral contraceptive
Sequential preparations
Progesterone only (Mini pill)
What are the benefits & limitations of new oral COMBINED pills that have a LOWER oestrogen dose?
High oestrogen associated with more side effects + higher risk of DVT
Lower dose lower adverse effects but less effective - need to take greater care with not missing dose after placebos
Can also cause break through bleeding
What is the mechanism of contraction of the COC pill?
Oestrogen - negative feedback to the hypothalamus & anterior pituitary to reduce FSH production (+/- LH depending on dose) and thus ovulation
Progesterone - changes the environment to reduce implantation & sperm access
- Thicker mucus to prevent sperm access
- Uterine contractions reducing implantation
- Changes to endometrium
Why is a high dose of progesterone not used in the COC?
High dose would result in negative feedback to reduce LH and thus prevent ovulation, but high dose associated with too many adverse side effects
What are the adverse effects of the COC?
Increased risk of DVT
Increased risk of breast & cervical cancer ??
Hypertension
Other - N/V, dizziness, wt gain, fatigue, depression, acne, irritability, decreased libido…
What COC and other risk factors lead to increased DVT risk?
The higher the oestrogen dose - higher dose
The type of progesterone used - cyproterone higher risk
Age over 35 yo
Smoker
What are the negatives & positives of COC in relation to cancer & other diseases?
Unclear but may increase risk of breast cancer - oestrogen + type of progesterone
Increased risk of cervical cancer - slight increase but should have regular screening
Combination pill abolishes risk of uterine cancer
Reduces risk of colorectal cancer, endometrial cancer, ovarian cancer & ovarian cysts
Protective effect on benign breast tumours
Reduces risk of bone fractures/osteoporosis
Reduction in risk of Fe deficiency anaemia - reduces dysmenorrhoea & menorrhagia
What are some other forms of contraception?
Vaginal ring - ethinyloestradiol + progesterone
- left in for 3 weeks, removed for 1 week
Progesterone only contraceptives
- Intramuscular injection every 12/52
- Subdermal implant - lasts up to 3 years
- IUD - leonorgestrel, lasts up to 5 years
Emergency contraceptive pill
What are the features of the emergency contraceptive pill?
Levonorgestrel
10x higher dose of progesterone than OCP
85% effective when taken early - most effective early but up to 72 hours effective
Changes endometrium and mucus to reduce implantation of embryo
What is the theory behind sequential preparations?
Varied pill dosage to try and mimic normal physiology in order to reduce some side effects
