Low dose progestational contraceptives primarily act on

Progesterone in bih control pills thickens cervical mucus (primary action): hinders the travel of sperm to the uterus and making it hard for sperm to enter the tubes and feilise the egg. thins the lining of the uterus: makes implantation unlikely. Progestogen only pills are generally less effective than other forms of oral contraceptive pill with a failure rate of 2 - 6 per 100 women years. The main side effects are Irregular, low-grade, breakthrough uterine bleeding but this may settle into a regular cycle after 6 - 9 months. Skin reactions, Breast fullness Depression Increased risk of ectopic pregnancy. Benefits include: Do not carry risk of thromboembolism Do not inhibit lactation - so can use when breast feeding Suitable for diabetics - as pills containing oestrogen exacerbate risk of aerial disease in such patients Suits smokers for whom oestrogen containing formulations are contra-indicated