So, what does the pill do and how does the pill work? There are three ways progesterone and oestrogen in the pill work in combination to prevent pregnancy.
Number one: The pill stops ovulation. Once a month you ovulate, your ovaries release an egg that meets a sperm and the egg becomes fertilised. The pill stops ovulation, no egg is released, sperm and egg never meet, and fertilisation doesn’t happen.
Number two: The combined pill makes the mucus in your cervix thicker, so sperm have a much harder time penetrating the womb and reaching the egg.
Number three: The pill thins your uterine lining. The uterine lining builds throughout the month and is what’s dispelled during your period. Normally, the egg is implanted into this lining where it can grow once fertilised. A thin uterine lining means less chance of an egg being implanted into the womb. The benefit of this is that the pill can make periods lighter and more manageable.
How long does it take for the pill to work?
If you’re wondering how long does the pill take to work: you can take it at any time but how long it takes to work will depend on where you are in your cycle.
So, if you take the pill within 5 days after the start of your period, you’re protected from pregnancy right away.
If you start at any other time during your cycle, you’ll be protected from pregnancy after 7 days of using the pill. If you have sex you’ll need to use a condom to protect against pregnancy.
The pill does not protect against sexually transmitted infections, so if you’re starting out with a new sexual partner, it may be a good idea to use a condom whether you’re taking the pill or not.
How effective is the combined pill?
There are two ways of measuring whether a pill is effective at preventing pregnancy. The first is done by ‘Perfect Use’ which is when you take the pill exactly as instructed, every day, without missing a dose. Taken perfectly, the combined contraceptive pill’s effectiveness is 99%.
‘Typical use’ is when someone takes the pill but may occasionally forget to take a dose or take it late. With typical use, the pill is 91% effective at preventing pregnancy. This means that around 9 in 100 women taking it over a year will become pregnant. One clinical study concluded that the pill is “effective, safe and well-tolerated”.
Again, in another study following 900 women in three different countries, Brazil, Egypt and China, there were only four unwanted pregnancies reported, all four because the pill wasn’t taken ‘perfectly’ (every day at around the same time). Similarly, in a study of over 2000 women taking the pill over a year, 19 became pregnant. Fifteen pregnancies of which were due to regularly missing doses or taking doses late.
So, answering, how reliable is the pill? With perfect use, very. However, missing the occasional dose or taking a dose late will affect this, increasing your odds of becoming pregnant by around 9%. The best way to ensure that the pill is as effective as possible at protecting against pregnancy is to take it at the same time every day.
Other things which can impact how effective the pill is include vomiting or diarrhoea, the antibiotic Rifampin, the antifungal Griseofulvin, HIV medicines, anti-seizure medicines, and the supplement St. John’s Wort. Speak with your clinician if you take these before or once prescribed the pill and use a condom as backup protection.
What are the advantages of the pill?
Some combined pills can help make periods more regular, lighter and less painful, ease symptoms of PMS (premenstrual syndrome), and are 99% effective at preventing pregnancy when taken correctly.
Some more advantages of the contraceptive pill include uninterrupted sex without the need to put on a condom, reduced risk of ovarian, endometrial and colon cancer, protection against pelvic inflammatory disease, and a reduced risk of fibroids, ovarian cysts and non-cancerous breast disease.
Some combined pills are also used to treat moderate to severe acne. Talk to your prescriber if you struggle with acne, are taking birth control pills, and have already tried topical treatments and antibiotics. They may be able to recommend a combined pill that can help your acne. It is important to note that the mini pill (progesterone only pill) may make acne worse.