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Illustration by Katrin Friedmann

Cycle A-Z

Why is my period late?

Reasons for a late period

by Jen Bell, Writer
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You go to the bathroom, pull down your underpants and… nothing. You expected your period to be here by now, but it’s not. Before you start to worry about why it could be late, take a deep breath and read this.

Your body is not a clock, and variation in your menstrual cycle is normal, especially if you are a teenager, breastfeeding or nearing menopause. Stress, travel, diet, illness and medication (including birth control) can also affect your cycle length, symptoms and the length and heaviness of your period. Up to 7–9 days of variation cycle-to-cycle is considered normal for adults.

It can be hard to know if your period is late, if you don’t know your average cycle length or when your last period was. With Clue you can view your recent period dates, cycle averages and predictions for your next three cycles. You can set a reminder to let you know when your period is coming, and to alert you if it’s late.

A hand holding a phone with the Clue app opened

Track your cycle with the Clue period tracker app.

The best time to take a pregnancy test

If you have a regular menstrual cycle (for example, your cycle length rarely varies by more than a couple days), then you are only at risk of pregnancy if you had unprotected heterosexual sex or had a high risk of sperm touching your genitals during your fertile window. This is the six days leading up to and including ovulation, usually around the middle of your cycle (note that the fertile window displayed in Clue is only an estimate — your actual fertile window might have different timing, which can vary cycle-to-cycle along with the start date of your period). You can take a pregnancy test about two weeks after your estimated ovulation day, but the earlier you take a test the less accurate it may be and some brands are more sensitive than others (1). You should probably take a pregnancy test or contact your healthcare provider if your period is nine or more days late.

If you have an irregular cycle (i.e. you don’t know when your period is going to come and the difference between your longest cycle and shortest cycle is more than 7–9 days), then unprotected sex or exposure of sperm on your genitals at most times represents a risk. You can take a pregnancy test about two weeks after your last unprotected sexual encounter, though the earlier you take a test the less accurate it may be and some brands are more sensitive than others (1).

If you get a negative result at first and your period still hasn’t come after a week, you might want to try taking another pregnancy test—just to be sure. The sooner you know if you are pregnant or not, the sooner you’ll be able to develop a plan (if you do continue a pregnancy, certain vitamins are usually recommended right away). You can get confidential testing and counseling in most healthcare providers’ offices and clinics.

Read more here about the different types of pregnancy tests and how to use them.

Unsure where to go?

The International Planned Parenthood Federation lists member associations in over 170 countries on their site. Planned Parenthood has over 600 clinics in the USA and Family Planning offers services in the UK, Australia and New Zealand. To find a service provider in Canada, try the Canadian Federation for Sexual Health (CFSH). If you are transgender there are many organizations worldwide that can help you to find a trans-friendly ob/gyn.

If you’ve had a negative pregnancy test and you haven’t had a period in more than 90 days, make an appointment with your healthcare provider. Tell them about your previous periods, cycle length and heaviness, and any other symptoms you have noticed. They may want to run a few tests to check if your cycle is being affected by another health condition.

A late period can be emotional, but try not to jump to conclusions until you find out what’s really going on. It’s completely normal for the length of your menstrual cycle to vary sometimes—maybe it’s nothing at all.

Download Clue to learn about your cycle and get accurate period predictions.