How do they work?
The dominant mechanism of action of all hormonal contraceptive methods is to prevent ovulation (the process in which a mature egg is released from the ovary). Hormonal contraceptives also thicken the cervical mucus to prevent the sperm reaching the egg and thin the lining of the womb to prevent implantation.
The only exception is the intrauterine system, where the primary mode of action is to thicken the cervical mucus to prevent the sperm reaching the egg and to thin the lining of the womb to impede implantation. Some women who have intrauterine systems will continue to ovulate; however, for some, the progestin may impact ovulation.
Non-hormonal contraception works by preventing a man’s sperm from joining a woman’s egg. Barrier methods also have the obvious advantage of protection from sexually transmitted infections.
How effective are they?
In ‘perfect’ use’ hormonal contraception is highly effective, and provides virtually 100 per cent protection from unwanted pregnancy. Non-hormonal contraception is less effective than hormonal contraceptive methods, and there is much more risk for women to get pregnant. It can be good practice to use a combination of both to protect from pregnancy and also STIs.
There is new advice that has improved the effectiveness of taking a combined contraceptive pill. No longer is the advice to take a combined pill for 21 days and then take 7 days off, but it is to take just a 4 day gap after 21 days or to run several packs together until you have a break through bleed and then take a 4 day break. This takes into account how some women have shorter cycles and how this could lead to the combined pill being less effective.
Long term contraceptives information.
We would often like to have a contraception that is longer lasting than a pill but the procedure to have them inserted puts us off. The insertion of an intrauterine device is uncomfortable but is similar to the discomfort of having a smear test and is over quickly. The doctor can give you something to make it less painful. It will need a longer appointment with a doctor trained in insertion or many sexual health clinics and private GP clinics offer an insertion service. Often you need to have a pregnancy test before insertion and sometimes a follow up appointment to check the strings of the coil are the right length. Intrauterine devices last between 3 and 10 years depending on the type and how old you are.
An implant is inserted under the skin in your upper arm using a local anaesthetic to numb the area first. Although it is relatively quick and easy it will need a longer appointment with a trained insertor or appointment in a sexual health clinic or private GP clinic. It is effective for up to 3 years.
The contraceptive injection or depo is given as an injection into your buttock or thigh every 12 weeks. It is very quick and easy to do and often your practice nurse can give it in a routine appointment.
