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Everything You Need To Know About Contraception

A recent Irish survey found that one third of couples were using the withdrawal method as their form of contraception. In the same research, 25% used condoms as their only contraception and 19% were using contraceptive pills. Considering the range of contraceptive options available these statistics are shocking.
Condoms are very effective in reducing the risk of bacterial infections such as chlamydia and gonorrhoea but not so good for viral infections such as herpes and HPV – the wart virus.

They are also not very good as a form of contraception – a study from the USA showed that couples using condoms as their only form of contraception had an 18% chance of pregnancy over one year.

So other forms of contraception need to be used to reduce the risk of pregnancy. There is a long list of options available – all of which are for the female partner to use. The only effective male choice is vasectomy or male sterilisation which is an operation and is typically done for older men who no longer wish to have anymore children.

The options include:

• Combined oral contraceptive pills
• Vaginal ring
• Contraceptive patch
• Progesterone – only pills
• 3 monthly injection
• Implant – lasts 3 years
• Copper intrauterine coils – last between 3 and 10 years
• Hormone intrauterine coils – last between 3 and 10 years

Combined pills

The most common type of pills are Combined Oral Contraceptive pills – COCs. These pills contain two hormones, an oestrogen and a progestogen. When taken correctly, COCs are a very effective form of contraception because they stop ovulation and have the added benefit of giving the woman a very regular 28 day cycle with predictable usually pain free monthly withdrawal bleeds.

Women with migraine, high blood pressure or a previous blood clot cannot take these pills. The oestrogen in the pill increases the risk of getting a blood clot in the leg or less commonly in the lung. Smoking and being significantly overweight (a body mass index (BMI) over 30) also increase clotting risk. If your BMI is over 35 your doctor should not prescribe these pills even if you are a non smoker.

Some anti epileptic medication or retrovirals for HIV can reduce the effectiveness of pills.

It is best to start pills at the beginning of the cycle because this gives immediate contraceptive protection and causes the least cycle disruption. So a woman who starts taking a COC within 24 hours of the start of a menstrual period will be safe for contraception straight away. It needs to be taken at the same time every day for three weeks out of four. If you are more than 12 hours late taking the pill it may not work. In the first few weeks of taking a pill, there may be some side effects as the woman adjusts to the hormones. Typical side effects are headaches, breast tenderness, bloating, mood swings and leg cramps. Intermittent bleeding can also occur during the first month. A three- month trial is a reasonable time to gauge whether or not a particular pill suits you. Choosing which pill is very much trial and error. Most women will be happy with whichever pill they start but about one in ten will have unacceptable side effects and will need to try a different formulation.

Major side effects are unlikely. There may be a slight increase in the risk of stroke but it is rare. The risk of a blood clot is about 1 in 1000. To put that in context, during pregnancy the risk of a blood clot is 3 in 1000 and immediately after a pregnancy it is 35 in 1000.

After stopping pills it usually takes about three months for periods to go back to normal.

Ring and Patch

Sometimes it is better to consider non pill methods. Both the vaginal ring and the contraceptive patch contain oestrogen and progestogen so all the rules regarding migraine, high blood pressure, weight apply to these contraceptives. They are also just as effective for contraception as the pill.

There is one vaginal ring contraceptive – Nuvaring. The woman places this in the vagina and leaves it there for three weeks. She then removes it and puts a new ring in 7 days later. A withdrawal bleed happens during the ring free interval. Most women leave the ring in place throughout the three weeks but it can be removed for up to three hours without causing a loss of contraception. The continuous low dose of hormones released from the ring means that it is often better tolerated than pills.

There is one contraceptive patch – Evra. The woman applies the patch to an area of clean dry skin on her upper arm, shoulder or buttock. She replaces the patch every week for three weeks and week four is patch free. The patch releases slightly more oestrogen than most pills so headache can be a side effect.

Progestogen Only Pill (POP)

For women who need to avoid oestrogen e.g migraine or blood pressure problems, a POP may be the solution. There are two POPs available.

Noriday contains norethisterone. It does not consistently stop ovulation. Its main mode of action is that it thickens cervical mucus and impedes sperm movement. This makes it slightly less effective than regular pills. It needs to be taken every day with no pill free interval and it must be taken within three hours of the same time every day. Its lower effectiveness and short time window makes it not suitable for use in younger, more fertile women so it is not recommended for women under age 30.

Cerazette contains desogestrel. This is also taken continuously with no pill free interval. However it does stop ovulation and has the same twelve hour window as regular pills so it is suitable for women of any age.

Since POPs are taken without a break there is no obvious time to have a bleed. Typically a woman starting a POP will find that they have more bleeding than usual for the first month or two and then bleeding stops completely. However she may have a bleed at anytime which some find unacceptable.

Depo Injection

This is a progestogen injection given into the muscle of the buttock every twelve weeks. It is very effective for contraception and tends to stop periods completely. However, it can take up to one year for periods to come back after stopping the injection.
Long acting reversible contraception i.e the subdermal implant and intrauterine coils have become more popular over the last few years because they are really easy to use, very effective for contraception and periods are back to normal within one month of stopping them. There is a less than 1% chance of pregnancy with any of these methods. The Implant is top of the list as the most effective.


We have one subdermal implant available in Ireland – Implanon NXT. This has been licensed in Ireland since 2002. The device is fitted under the skin of the inner aspect of the upper arm with the assistance of some local anaesthetic. It lasts for three years. The main problem with this method is that it causes irregular bleeding because it stops the ovarian cycle.

Interestingly the usual list of side effects – headaches, breast tenderness, bloating – that are seen with pills rarely happen with the implant.

Intrauterine Systems (IUSs)

There are now three IUSs on prescription. They all release small amounts of the progestogen. The latest Kyleena is particularly useful for women who have heavy periods. So those who tend towards heavier periods i.e older women and women who have had children usually opt for this coil.

However, like all intrauterine devices, it is also suitable for women who have not had children. Women with normal/ light periods usually find that they have no periods after the first six months or so. It lasts for five years.

The newest, Kyleena has been on prescription since April 2017. It releases less than half the amount of progestogen compared to Mirena so most women will continue to have regular but light periods. It also lasts for five years.

Jaydess is a smaller device that releases even less progestogen. It has a three year license.

Copper intrauterine devices (IUCDs)

Some women want an effective hormone free method of contraception. A copper coil fits the bill. There are several different types of coil but the gold standard is the copper T 380. This is effective for ten years.The crucial question to ask is “How heavy / painful are your periods?” For women who already have heavy bleeding, copper coils may make the blood flow unmanageable. Similarly, if periods are painful/ crampy a copper coil is only going to make the symptoms worse. So they are suitable for women with light to moderate flow relatively pain free periods.


Ref: Trussell et al Contraceptive Technology 20th ed 2011

You can find out more about contraception at the Well Woman Centre. 

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