Daylight Saving Time and Your Birth Control Pill

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For maximum pregnancy prevention, you should take your birth control pill at about the same time every day. Whether you take progestin-only or combo pills, this ensures your body has enough hormones to keep you from ovulating.

You've probably been told if you forget a pill or take it earlier or later than usual, it could become less effective. So, when it comes to daylight saving time, you may wonder about the timing of your birth control.

This article discusses whether daylight saving time affects when you should take your birth control pill and how you should adjust.

Packages of birth control pills with calendar background
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Spring Forward

Most medical professionals agree you have a one-hour to two-hour window for taking your birth control pill without compromising its effectiveness. This means if you take it an hour earlier or an hour later, it should still work just fine.

Say you always take your pill at 10 p.m. When daylight saving time goes into effect, the clocks "spring forward" an hour. You can still take your pill when the clock says 10 p.m. even though it's not 24 hours after your last one. You don't necessarily need to adjust for daylight savings.

If you'd rather be super-cautious, you can always adjust your pill-taking time. This means at the beginning of daylight saving time, you'd switch from 10 p.m. to 11 p.m.

Really want to keep your "usual" time? After your placebo week and starting with a new pack of pills, go back to taking them at your "normal" time. In the above example, you could take them at 10 p.m. again.

Recap

Ideally, you should take your birth control pill within the same one-hour to two-hour period each day. When turning clocks forward in the spring, you can either take it at the same time as usual or an hour later.

Fall Back

When daylight saving time is over, the clock is moved back one hour. In this case, it may be wise to just take your pill one hour earlier than you normally would. This helps ensure your hormone level doesn't drop too much.

You can always go back to taking the pill at your “regular” time after the placebo week is over. Resume your usual time when you start the next pack of pills.

Taking your pill an hour earlier or later generally does not matter. However, taking your pill one hour earlier (as opposed to one hour later) is a slightly better option.

Also, keep in mind that computer software programs and smartphones will usually (but not always) automatically update the time.

You might rely on a reminder email/text, phone alarm, or birth control app to remind you to take your pill. If so, make sure your devices have adjusted the time for the start or end of daylight saving time.

History

Since World War I, daylight saving time has been used in the United States and in many European countries. During daylight saving time, you advance your clocks during the spring/summer months by one hour. This allows daylight to last an hour longer during the time people are usually awake.

Places that follow daylight saving time will move their clocks forward one hour near the start of spring and adjust them back to standard time in autumn. You'll see the terms "spring forward" and "fall back" when referring to this.

Daylight saving time was not formally adopted in the US until 1918. On March 19, 1918, an official bill was created to preserve daylight and provide standard time for the United States.

After World War I ended, the bill was not very popular. President Wilson ended the bill but allowed each state to decide whether to observe daylight saving time. They could also decide when it started and ended. This created a lot of confusion.

In order to create one pattern across the country, President Lyndon Johnson signed the Uniform Time Act of 1966. It was passed into law on April 13, 1966. It established a uniform period to observe daylight saving time while allowing states to be exempt by passing a state law.

Recap

Daylight saving time was started in the U.S. in 1918 and made into law with the Uniform Time Act of 1966. The goal was to have an extra hour of daylight during waking hours in the spring and summer. States can be exempt from daylight saving time if they pass a state law.

When It Happens

Most of the U.S. begins daylight saving time at 2 a.m. on the second Sunday in March. They go back to standard time on the first Sunday in November.

In the spring, clocks "spring forward" from 1:59 a.m. to 3 a.m. In the fall, clocks "fall back" from 1:59 a.m. to 1 a.m. Each time zone in the U.S. switches at a different time.

The following states and U.S. territories do NOT observe daylight saving time:

  • Arizona
  • Hawaii
  • American Samoa
  • Guam
  • Puerto Rico
  • The Virgin Islands
  • The Commonwealth of Northern Mariana Islands

The beginning and ending of daylight saving time can sometimes be confusing. It may cause problems when traveling, sleeping, or taking medications (like the pill).

Summary

Birth control pills may be most effective when taken at about the same time every day. During daylight saving time, your clock changes an hour, so you may be taking your pill earlier or later.

Most medical experts say you should take your pill within a one- to two-hour window every day. So the pill should still work fine if you take it an hour earlier or later.

If you'd rather be cautious, you can take your pill an hour later when you "spring forward." You could also take it an hour earlier when you "fall back."

Whichever time you decide, you can go back to your usual time after your placebo week as you start a new pill pack.

A Word From Verywell

When it comes to daylight saving time, there is no need to become overly anxious about adjusting when you take your pill. As long as you're still taking your pill within an hour of when you normally do, put your worries away!

You will have maximum protection as long as you take the pill at about the same time every day.

Frequently Asked Questions

  • Why is the pill taken at the same time every day?

    The hormones in the pill stop you from ovulating. Your body metabolizes the hormones in the pill each day. If the level of hormones drops and a new dose isn't provided (via the next pill), you may begin ovulating again. This is especially true for progestin-only pills. If you take those pills more than 24 hours apart, you may lower the effectiveness of the pill.

  • What affect does changing time zones have on the pill?

    For the pill to be effective, it is supposed to be taken at the same time every day. Thus, if it's regularly taken at 10:00 a.m. Eastern time, it would need to be taken at 7:00 a.m. Pacific time.

  • What happens if you take a birth control pill a few hours later than normal?

    The level of hormones in the body drops if a birth control pill is taken too late. To prevent getting pregnant, it would be necessary to take the missed dose as soon as possible and then take the next pill at the regularly scheduled time (which may mean taking two pills within 24 hours).

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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Planned Parenthood. Can daylight savings time mess up the effectiveness of my birth control pills?

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  4. Beagan, G, Wegman C. Daylight saving time 2019 ends Sunday: It's not plural and was never about the farmers. USA Today.

  5. Gebel Berg E. The Chemistry of the Pill. ACS Cent Sci. 2015;1(1):5–7. doi:10.1021/acscentsci.5b00066

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