Does Alcohol Affect Birth Control? What You Need to Know

But there are still some things you should know about alcohol and birth control, particularly: 

• How birth control affects your alcohol tolerance
• How alcohol can mess with the almighty birth control pill schedule
• How you can work around the indirect effects of alcohol on birth control

Keep reading to find out where you can slip up if you’ve had a few too many, and what you can do about it. ‍

Types of birth control and their effectiveness‍

First, here’s your baseline efficacy rate––how well each method protects against pregnancy––for each type of birth control, with stats from the Society of Obstetrics and Gynaecology:
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Pill: When taken every day at around the same time, 91%–99% effective

IUD: When replaced every three to ten years, depending on the type, more than 99% effective

Ring: When replaced once a month, 91%–99% effective

Patch: When replaced once a week, 91%–99% effective

Shot: When taken every three months, at least 94%–99% effective‍

‍Does birth control decrease alcohol tolerance?‍

Fun fact: If you’re on the pill, your body metabolizes alcohol more slowly than people who aren’t. Your liver is already processing the pill, so adding alcohol is sort of like adding to its workload.

Just like when you’re on your period, you’ll be drunk for longer when you’re on the pill. ‍

Does alcohol make birth control less effective?

Alcohol does not have a direct effect on the efficacy rate of any birth control method. There’s nothing about the chemical interaction between alcohol and hormonal birth control that can make it less effective.  

That being said, we’re not exactly at peak performance during or after a night of heavy drinking. Alcohol can change our behaviour, which can change the way we adhere to the schedules that birth control methods depend on to remain effective. 

Drinking can affect schedule adherence in two main ways:‍

1. Alcohol can make you forget to take your birth control.‍

This is especially relevant if you’re on the pill, which requires you to take it at around the same time each day. If you’ve been drinking heavily, you may get carried away with your night and forget to take it. 

The pill becomes less effective if you don’t take it at the same time every day, especially progestin-only pills, which should be taken at the same time daily to prevent pregnancy.‍

2. Alcohol can make you vomit your pill.‍

So let’s say you drink so much that you vomit (it happens to the best of us, no judgment). If you took your pill less than two hours before getting sick, you may not have absorbed it.‍

General rule of thumb: If you vomit within two hours of taking your pill, treat it as a missed pill and take another one. If you’ve taken your pill more than two hours before vomiting, you’re still protected.  ‍

If you miss a pill:‍

First of all, don’t panic! If you miss a pill, check out this resource by the Society of Obstetricians and Gynaecologists of Canada, and use back up protection like condoms for a week. ‍

How can I make sure drinking doesn’t affect my birth control?‍

If you’re looking forward to a night of drinking, here are some ways to keep your birth control schedule intact:‍

Take your pill in the afternoon. While people most commonly take their birth control pill in the morning or at night, you may find your schedule is constantly disrupted at these times, either because of drinking or not sleeping well. Set an alarm and take your pill in the middle of the day, and you won’t have to worry about it at all during a night out… or the morning after.‍

Set an alarm: If you don’t want to take your pill in the middle of the day, set an alarm on your phone for the morning or evening and stick to it. Just remember you may need to take your pill in the middle of a party or within the depths of a hangover.  ‍

Carry condoms: We know it’s tempting to get rid of your condom stash if you’re in a monogamous relationship and taking birth control, but it’s useful to keep a few on hand in case.  

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One last reminder, because we wouldn’t be doing our job if we didn’t: birth control doesn’t protect against STIs. Especially if you’re having sex with someone new, always use a condom.