Wondering why your period is fashionably late? Any disruptions to your menstrual cycle can be alarming, but you might not need to hit the panic button just yet! Here at Unfabled, we're all about demystifying your hormones and helping you understand your body, so here's the thing: a late period doesn't necessarily mean you're pregnant or have a menstrual health condition. We've got the scoop on some the most common reasons behind late periods, and only one of them is pregnancy. Let's get into it.

First up, when is a period actually considered late?

The average menstrual cycle lasts 28 days, which means for most people, they will get their period every 28 days. That being said, only about 16% of us actually follow that script. It's totally normal for the cycle to be anywhere from 23 to 35 days long. So, if your period takes a small detour now and then, it might be completely normal. 

Periods typically last between 2 to 7 days each cycle. It's normal for your period to vary slightly each month – perhaps being a day or two early or late every once in a while – but if your period fluctuates by around 7 to 9 days each month, then it's considered an irregular period. 

If you don't have any known menstrual conditions, and your period should start within 24 to 38 days of your last period, depending on your usual cycle. If you're 7 days past your expected period due date, your period is officially late. If you still haven't started your period after six weeks, you can consider your late period a missed period.

14 reasons for a late period

1. Stress

Feeling like you're juggling a circus lately? Emotional or physical stress can throw your hormones for a loop, hitting pause on your period's monthly visit and making your period late. Take a breather, maybe try some meditation or a Netflix binge – your hormones will thank you.

2. Sudden weight loss

Shedding pounds quickly can throw hormones out of whack, impacting your menstrual cycle. Severely restricting the amount of calories you eat stops the production of hormones needed for ovulation, so dieting and associated weight loss could be wrecking havoc on your cycle and causing your late period. A balanced lifestyle is key – and will help you regulate your cycle. 

3. Excessive exercise

Have you been putting in extra hours at the gym? Intense physical activity can actually halt your menstrual cycle by slowing down your metabolism. This slowdown prompts your body to conserve energy, potentially leading to the interruption of ovulation. If you suspect that your rigorous workout routine is the reason behind your late period, it's crucial to consult with your healthcare provider for personalized guidance.

4. Post-morning after pill delays

The morning after pill comes with a host of potential symptoms like spotting (irregular bleeding between periods), a heavier or lighter menstrual flow, a shorter or longer period, or an early or delayed period. If you've recently taken the morning after pill, it's natural to be panicking about your period being a bit later than expected. But, the morning after pill works by delaying ovulation. So, if you've taken it before ovulating, there's a chance it could have extended your cycle and made your period late. 

5. It could be polycystic ovary syndrome (PCOS)

If your period is irregular and you're frequently experiencing delays, it could be a sign of Polycystic Ovary Syndrome, or PCOS. PCOS can disrupt the regular release of eggs, leading to delayed or missed periods. Keep an eye out for additional symptoms, track your cycle and consult a healthcare professional for diagnosis and guidance.

6. You could be starting perimenopause

As early as your mid-30s, perimenopause might start playing with your hormones, causing irregular periods. Don't fret – it's a natural transition, but consulting with your healthcare provider is wise.

7. Thyroid disease

A thyroid hormone imbalance may result in a disrupted menstrual cycle. When thyroid hormone levels are too low or too high, it can cause prolonged menstrual bleeding, anovulatory cycles (cycles without ovulation), and irregular periods. In some cases, thyroid disease can also cause periods to stop for several months, which is called amenorrhea. 

8. Primary Ovarian Insufficiency (POI)

POI occurs when the ovaries stop working as they should before age 40. People with primary ovarian insufficiency can have irregular or occasional periods for years. Just as we said with PCOS, if you're experiencing consistent irregularities with your period, it's definitely worth checking in with your GP so they can let you know if it is Primary Ovarian Insufficiency or down to other reasons. 

9. Long distance travel

Yes, travel can actually impact your cycle, especially if you've recently travelled across timezones. Travelling can directly influence your hormones and the menstrual cycle due to its associations with the circadian rhythm – the body’s “inner clock”. The further that your travels go, the more likely your hormones and menstrual cycle are to be thrown out of whack. This might mean that when travelling, your period might make an appearance earlier or later than expected or it could also be lighter or heavier. 

10. Poor sleep

A consistent sleep schedule keeps your biological schedule consistent too. But when your sleep schedule is thrown off, the secretion of hormones is not as consistent and regular as it usually is, which in turn affects the secretion of reproductive hormones. This could lead to fluctuations in your cycle, like a late period.

11. Some medications

Certain medications can cause disrupt your period. If you've recently switched up your medication and have since experienced period delays, it's worth touching base with your GP to see if your medications could be to blame

12. Hormonal contraception

Hormonal contraceptives can also influence your cycle, and sometimes lead to late periods. Different types of contraceptives can affect your menstrual cycle in different ways. Some contraceptives are associated with heavy periods, some with light periods, and some with amenorrhea. You can learn more about how the pill impacts your cycle here.

13. You've only recently had your first ever period

A normal menstrual cycle can vary. This is especially true for young people who are just starting to get their periods or for people who have not had periods for several years (due to hormonal birth control, for instance) and are only just starting to menstruate again.

If you've only had a few cycles, or just had your fist ever period, you may go months without another one until a regular pattern begins. Similarly, people who have not had a period due to contraceptive use, hormonal therapy, or illness may not resume regular, monthly periods right away, either.

14. Pregnancy

We couldn't forget this one – whether it's something you're planning or something you're hoping to avoid, it's important to remember that a late period could  be due to pregnancy if you're sexually active. The surest way to find out? Take a pregnancy test. 

The bottom line

There you have it, 14 reasons why your period could be late – from pregnancy through to PCOS, changes in your diet, stress and more. Remember, your body is unique, and while late periods might raise an eyebrow, understanding the underlying reasons can bring clarity and peace of mind.