The Contraceptive Patch: What is it? How it Works | Treated

Birth control patch

Table of contents

Medically reviewed by

Dr Daniel Atkinson

GP Clinical lead

on November 03, 2022.

Was this article useful?

What is a birth control patch?

The birth control patch, also known as the contraceptive patch, is a relatively small, square-shaped patch that sticks to the skin. It releases hormones which work in the body to prevent pregnancy.

Here in Canada, the brand of contraceptive patch we use is known as Evra. It’s a highly effective method of birth control that may be preferable for women who don’t like swallowing pills.

How does the contraceptive patch work?

The contraceptive patch is a type of transdermal medication. Transdermal means “through the skin”.

Contraceptive transdermal patches contain two synthetic variants of naturally occurring female hormones – oestrogen and progestogen. These synthetic hormones are used in a number of other combined contraceptive methods, including the combined pill.

To prepare the body for pregnancy each month, levels of oestrogen and progesterone will rise and fall naturally, causing certain actions to take place. This includes the release of an egg, also known as ovulation.

When someone uses the contraceptive patch, the addition of synthetic hormones changes the body hormone levels, which then changes how the body prepares for pregnancy. The hormone changes caused by the patch protect you against pregnancy in three main ways:

Ovulation doesn’t happen, so no eggs are released
Vaginal mucus thickens, making it harder for sperm to pass through the cervix
Uterine lining gets thinner, meaning that in the rare case an egg does get fertilized, it is unlikely to be able to implant itself

How to use the Evra Patch

Using the contraceptive patch is relatively simple. You apply the patch to an area of the skin of your choice and wear it for seven days. On the eighth day, change your patch. Do this for three weeks, and then spend the fourth week patch-free. (Contraceptive effectiveness isn’t affected during your patch-free week.)

In the week you don’t wear a patch, you may experience what’s called a ‘withdrawal bleed’, which might feel similar to a period. However, some people don’t experience this. Either way, it’s nothing to worry about.

After seven days without a patch, you apply a new patch and repeat the four week cycle again.

Where to put the contraceptive patch

It’s common to see the patch used on the upper arm but you can stick the contraceptive patch almost anywhere, providing the area of skin you choose is dry, clean and not too hairy. You must also avoid wearing the patch on skin that’s sore or irritated, or on the breasts. Lastly, avoid placing the patch on an area of skin that regularly experiences a lot of rubbing or friction. The patches are made to withstand this (and you can also wear them in the bath or shower), but it’s always good to be extra-careful.

Doctors sometimes recommend switching up where you stick the patch each time you change it. This can help reduce skin irritation.

Here’s what to do if your patch does come off. If the patch has been off for two days or less:

Apply a brand new patch
Change it on the normal day that you would
You’re still protected if you’ve used your patch in the correct way for the last seven days. If you’re on your patch-free week, you are still protected provided you used the patch correctly in the seven days that led up to your patch-free week

If the patch has been off for two days or more:

Apply a brand new patch. Do not try to re-apply the old one
If you’re in the first or second week of your patch cycle, change it on the day you normally would
If you’re in the third week of your patch cycle, you need to start a new cycle. When you apply a new patch, that is the first day of your first week in the cycle
Use an additional method of contraception, like condoms, until you’ve worn a new patch for a full seven days

When does the patch start working?

If you’re wondering how long it is before the Evra patch becomes effective, the answer is relatively straightforward.

If you start using Evra on the first five days of your period, you’ll enjoy immediate contraceptive protection.

If you decide to start using it on the sixth day of your period, or on a non-period day, you are not protected straight away and should make use of additional contraceptive methods like condoms. Do this for seven days, after which you will be protected against pregnancy.

If you have short menstrual cycles (meaning your cycle is 23 days or less) you’re only protected immediately if you start using the patch on day one to four of your period. If you start using it on the fifth day or on a non-period day, you need to use additional contraception for seven days.

How effective is the patch?

The birth control patch effectiveness rate is relatively high. If you use the patch correctly — meaning you wear it perfectly for seven days, change it on the eighth day, repeat for three weeks and then spend seven days patch-free, plus it never falls off — it is more than 99% effective at preventing pregnancy.

If you use the patch typically, and most people fall into this category, its effectiveness lowers to around 91%. Meaning 9 out of every 100 women will get pregnant who use the contraceptive patch typically.

So the contraceptive patch is highly effective even with just typical use, but it’s better to do everything you can to ensure you wear it properly and change it at the correct time each week.

Contraceptive patch benefits

Preferable for women who don’t like taking or swallowing pills.
You don’t have to apply the patch daily, as you’d have to take a contraceptive pill.
Instead it’s applied weekly for three weeks followed by a ‘patch-free’ week.
Easy to apply and wont interrupt sex the same way a condom might.
The contraceptive patch hormones are absorbed directly to the bloodstream, not the stomach as is the case with pills. So if you vomit, contraceptive protection isn’t affected.
It can positively impact periods - making them more regular, lighter and sometimes less painful.
Can help with premenstrual symptoms (PMS).
May reduce the risk of ovarian, womb and bowel cancers.[2]

Contraceptive patch disadvantages

You can’t just apply the contraceptive patch and forget, you need to change it every week and remember to change it. If you’re more likely to forget, you may benefit more from contraceptive methods like the implant or IUD.
Certain medications can make the patch less effective or increase the risk of certain side effects.
You may not be allowed to use the patch on certain medications.
Spotting between periods is common when you first start using the patch.
When you first start applying the patch you may experience side effects.
Examples include headache, nausea, breast tenderness and changes in mood.
You’re not protected against sexually transmitted infections when you use the contraceptive patch.
It can cause irritation or soreness to the skin. Avoid this by changing where you apply the patch each time.
It may at times be visible.

This page was medically reviewed by Dr Daniel Atkinson, GP Clinical lead on November 03, 2022. Next review due on November 03, 2024.

How we source info:

When we present you with stats, data, opinion or a consensus, we’ll tell you where this came from. And we’ll only present data as clinically reliable if it’s come from a reputable source, such as a state or government-funded health body, a peer-reviewed medical journal, or a recognized analytics or data body. Read more in our editorial policy.

Let’s help you choose better.

Back to the top