Understand what you have been using and how it works
When considering whether the pros and cons of continuing with or stopping your current method of chemical contraception, it’s helpful first of all to understand how it works. We’ll consider firstly how they work as contraceptives, then consider the other reasons people might choose to use them.
First and foremost: contraception.
“The Pill” – The Oral Contraceptive Pill
The Pill contains a combination of two hormones, an oestrogen and a progestogen. Once you start it, it typically takes around 7 days to start providing protection (but read the leaflet). It only provides protection as long as you continue to take it correctly, and there are no other factors to prevent it working (such as vomiting).
How it works:
Preventing ovulation
Thickening the cervical mucus to make it hard for the sperm to move through
Thinning the lining of the uterus, making it more difficult for the fertilised egg to implant in the wall of the uterus
Effectiveness Rating:
99%, but around 92% in research studies, probably because of women not using it correctly (e.g. not allowing enough time for it to start working again after they have been vomiting, or forgotten to take it
“The Coil” – The Hormonal IUD , the Mirena
On the other hand, the Mirena involves no oestrogen, but rather a progestogen alone. This progestogen is secreted into the uterus from the IUD and provides contraception for around 5 years.The Mirena itself is a plastic device that is inserted into the wall of the uterus.
How it works:
Thickening the cervical mucus to make it hard for the sperm to move through
Thinning the lining of the uterus, making it more difficult for the fertilised egg to implant in the wall of the uterus
Effectiveness Rating:
99.9%
“The Rod/Implant” – Implanon
Implanon is a small rod inserted by a doctor via into the fat underneath the upper arm. It provides 3 years’ worth of contraception. Like the Mirena, it is progestogen-based (no oestrogen).
How it works:
Preventing ovulation
Thickening the cervical mucus to make it hard for the sperm to move through
Thinning the lining of the uterus, making it more difficult for the fertilised egg to implant in the wall of the uterus
Effectiveness Rating:
99.9%
“The Injection” – Depo Provera (DMPA)
Like the Mirena and Implanon, the Depo Provera injection is a progestogen (no oestrogen).
How it works:
Preventing ovulation
Thickening the cervical mucus to make it hard for the sperm to move through
Effectiveness Rating:
99%
Second: Other desirable side effects
Lighter Periods
Many women on the Pill and the Mirena report lighter periods. The MIrena thins the lining of the uterus (the endometrium), which means there is less blood to shed. This can be unpredictable – some women have no or infrequent bleeding on the Mirena. Other women have continual spotting.
A distinction that is important to make here is between “periods” and “withdrawal bleeding”. A period is the bleeding (shedding of the endometrium) that happens around two weeks after ovulation, when the egg has not been fertilised (i.e. you are not pregnant). A withdrawal bleed is bleeding (shedding of the endometrium) that happens when levels of hormones fall, even when there has not been ovulation. So on the Pill, you no longer experience “periods”, but rather, withdrawal bleeds. So, it is not actually that your periods get lighter. You no longer have periods while on the Pill. Instead, you take hormones for a while, and then you stop taking them briefly, leading to a withdrawal bleed. The hormones you take supersede your own natural hormones. So, the Pill acts to mask period problems such as heavy periods, by leading to a predictable withdrawal bleed when the artificial hormones are stopped. This is a desirable effect for some women, as the heavy bleeding may be causing them some problems.
Less Painful Periods
Every month I see dozens of women who were put on the Pill for painful periods. In fact, this often starts in the early teenage years. While the Pill, by stopping periods and replacing them with predictable withdrawal bleeds, can reduce pain intensity when bleeding, there are some considerations we’ll address more in the next post, such as missing a diagnosis of endometriosis due to complacency once the pain eases.
More Regular Periods
From what you know now about the difference between periods and withdrawal bleeds, it’s easy to see that the Pill does not “regulate your periods”, despite that often being how doctors describe it. Rather, it stops your periods and masks the cause of the irregularity by giving you a predictable withdrawal bleed at regular intervals (i.e. whenever you stop taking the hormone pills). This can be very convenient. Lots of women – especially teenagers – have told me how much easier it is now that they can “plan for their periods”, or just keep taking the Pill continuously so they can “skip their period”. In the next post we’ll talk more about the darker side to this, including masking serious causes of irregular bleeding such as polycystic ovarian syndrome.
Improvement in Anaemia and Low Iron Status
One serious problem caused by heavy menstrual bleeding is anaemia, the end stage of low iron status. Anaemia is a serious problem and cannot be ignored. Even in women without anaemia, low iron stores can be a cause of fatigue and exhaustion. In women in whom the anaemia cannot be otherwise resolved, going on the Pill can be a lifesaver to stop the iron dropping further by replacing heavy periods with predictable light withdrawal bleeds.
Improvement in Acne
I see an enormous number of women who are on the Pill “for their skin”. It is certainly true that certain types of contraceptive Pill can reduce or resolve acne. It does this by raising the levels of a hormone called SHBG (sex hormone binding globulin), which is like a police officer that handcuffs the criminals – the hormones causing the problems, usually testosterone. Certain types of Pill are androgen-blockers, which means they specifically block testosterone as well.
In the next post we’ll talk about some of the considerations to be aware of if choosing to use any of these methods of contraception.