Why Is My Menstrual Cycle Getting Longer?

If your period used to show up like clockwork and now you never know when your next one will arrive, it’s natural to wonder what’s going on. Same thing when the bleeding starts to last a week rather than your standard 5 days. (Or both of these!) 

That unpredictability can be annoying, especially as you get older. Let's be real: If you thought the days of getting caught off guard by your period were long behind you, we feel you. But if you suddenly feel as unprepared as you did in your teens, you’re in good company: Research suggests irregular cycles are nearly twice as common for women in their 50s than those in their late 30s. These shifts are often tied to hormone changes in the years leading up to menopause. But that doesn’t mean you should shrug off ongoing changes or guess your way through what’s happening every month.

Ahead, we’ll walk through what a longer menstrual cycle can mean, the most common reasons it happens, simple at-home checks, and when it’s smart to get care.

What’s the Difference Between a Longer Cycle and a Longer Period?

Before we get into possible causes, let’s define a few basics, because a “longer period” can mean two different things.

The first day of your period marks the start of your menstrual cycle, which ends the day your next period begins—that’s the length of your cycle. Your period length refers to how many days you actually bleed during a single cycle. A typical period lasts anywhere from 2 to 7 days, though it can vary from one cycle to the next.

A longer menstrual cycle usually means more days between periods, while a longer period means the bleeding lasts for more days than usual. This distinction is important because a longer cycle and a longer period can have different causes, and you can experience one without the other. Clarifying which change you're noticing is the first step to figuring out why it’s happening. 

What’s a “Normal” Range? 

A “normal” menstrual cycle is usually 24 to 38 days, but some variation from month to month is common. 

What matters most are your personal patterns. A cycle that’s usually 32 days long and occasionally shifts to 34 days is common, and that’s very different from a cycle that suddenly stretches much longer than usual or becomes less predictable.

Pattern shifts don’t always mean something is wrong, but they’re worth tracking. If you notice sudden, significant, or ongoing changes in your menstrual cycle length, consider checking in with a healthcare professional. This can include cycles that are consistently longer than about 38 to 40 days or if you go 60 to 90 days between periods. 

Common Reasons Why a Period Cycle Lengthens 

When your menstrual cycle starts getting longer, it’s usually tied to hormone changes. These shifts can affect cycle timing and make the span between periods stretch out. Below are some of the most common reasons this happens.

Perimenopause

Your cycles might be all over the place in the years leading up to menopause, which are known as perimenopause.

“In perimenopause, cycles can be longer or shorter and heavier or lighter,” says Midi Health Clinician Sonya Carothers, APRN, PhD, FNP. “That’s often how women know something is changing.”

This transition phase usually begins in your mid-to-late 40s (though it can start earlier or later), as your reproductive years wind down. Hormones that regulate your cycle, like estrogen and progesterone, fluctuate as they decline. So ovulation may happen later than usual or not at all in some cycles. These changes can lead to irregular cycles, including longer gaps between periods, over time.

During cycles when you don’t ovulate, you still may experience bleeding, Carothers explains. But since ovulation can still happen if you’re having periods occasionally, pregnancy is still possible.

Studies suggest that longer menstrual cycles may become more common in the later stages of perimenopause, with stretched-out gaps between periods happening more often as menopause approaches.

Stress, Sleep Loss, and Travel 

Some lifestyle factors, like your stress level, can also cause a longer menstrual cycle. When you’re feeling tense or frazzled, your body releases more cortisol, which can delay ovulation and interfere with the hormones that regulate your cycle. As a result, cycles can become longer or less predictable.

Not getting enough sleep––whether it’s from stress, work, or travel––can also throw off the hormones that keep your cycle on track. Inadequate sleep has been linked to longer or irregular menstrual cycles. Jet lag can also throw off your circadian rhythm, and research shows that this can temporarily knock your cycle out of whack.

Weight Changes, Intense Exercise, or Under-Fueling

Major weight changes (whether you lose or gain weight) and intense exercise may disrupt hormones that control ovulation, especially when you don’t eat enough to support your activity level. That disruption could delay ovulation––or prevent it altogether––making your cycle longer than usual. 

Thyroid or Prolactin Changes

Not all menstrual cycle changes start with reproductive hormones, though. The thyroid, for example, is a small butterfly-shaped gland in your neck that releases hormones, which (among other things) help control your cycle. When thyroid hormone levels are too high (hyperthyroidism) or too low (hypothyroidism), cycles may be longer or less predictable. High levels of prolactin, another hormone, can also cause irregular cycles. 

PCOS 

Polycystic ovary syndrome (PCOS) causes a hormonal imbalance that affects ovulation. It’s a common cause of missed or out-of-whack menstrual cycles, which can extend well beyond 24 to 38 days. Insulin resistance is often part of the cause of PCOS. (It can also cause excess testosterone, a condition known as hyperandrogenism, leading to unwanted hair and skin changes.)

Contraception Changes 

Sometimes, there’s a really simple explanation for a longer cycle, like adding a new medication to your routine. Starting, stopping, or switching hormonal birth control can throw off your cycle’s timing for a few months as your body adjusts. Taking emergency contraception can push back ovulation and make your current cycle longer than usual. 

Pregnancy

If your period is very late and there’s any chance you could be pregnant, take a home pregnancy test to be sure. Early pregnancy can sometimes show up as light bleeding or spotting that you might confuse for your period. So testing can provide clarity. 

Why Your Period May Last Longer Than Usual

If your period is longer than you’re accustomed to—meaning you’re bleeding for more days—that could point to different causes than a longer menstrual cycle. Prolonged bleeding might be linked to physical changes in the uterus or month-to-month hormonal shifts. But there can be some overlap.

Common reasons your period lasts longer than usual include:

• Anovulatory cycles (cycles without ovulation): When an egg isn’t released, the hormone shift that typically tells your body to stop bleeding doesn’t happen. So your period might last longer or feel more irregular than usual.
• Fibroids, polyps, or adenomyosis: These noncancerous growths and tissue changes in or around the uterus are common, especially as you get older. They don’t always cause symptoms, but when they do, they often show up as longer periods or heavier bleeding with clots.
• IUDs: A copper IUD can make periods longer or heavier for the first few months after insertion. Hormonal IUDs tend to do the opposite over time, often leading to lighter or shorter periods, though spotting can happen early on.
• Certain medications: Some meds can affect your period even if they don’t change the length of your cycle. Blood thinners, for example, can make periods heavier or longer. Some antidepressants (SSRIs) or steroids can also make your periods irregular.

If your periods are lasting longer than usual or getting harder to manage, that’s a good reason to check in with a healthcare professional.

Quick At-Home Triage 

Cycle changes can be confusing, especially when periods start lasting longer or showing up unpredictably. It doesn’t necessarily mean something is wrong, but a bit of at-home tracking can help you make sense of what’s happening.

Start by tracking two cycles. You can use an app, calendar, or good old-fashioned pen and paper to jot down:

• when bleeding starts and ends
• how heavy your flow is, including whether you see any clots
• cramps or pelvic pain
• potential triggers, like missed birth control pills, travel, or stress

If there’s any chance you could be pregnant, take an at-home test. (Yes, many women have surprise pregnancies in their 40s.)

It’s also worth thinking about what’s changed recently, such as new medications, unusual stress, or poor sleep. Pay attention to any new symptoms, too. Fatigue, dizziness, heat or cold intolerance, sleep changes, or hot flashes can offer clues about thyroid shifts, iron levels, or perimenopause.

Diagnosis and Treatment Options 

A healthcare professional, like a Midi clinician, can help you understand why your period or cycle is getting longer.

An evaluation usually starts with a conversation about your recent cycles, symptoms, medications, and any changes in health or routine (this is where tracking really pays off). From there, your clinician may recommend a few targeted tests to fill in the picture. 

Tests can include:

• a pregnancy test
• basic blood work to test thyroid function and iron levels
• blood sugar or hormone tests if PCOS is a possibility
• an ultrasound to check for fibroids, polyps, or other uterine changes

Then, the two of you can come up with a treatment plan that works for you. It should be designed to address any underlying causes, manage bleeding, protect iron stores, and align with your health goals. 

A Range of Treatment Options 

Typically, a mix of lifestyle changes and medications can help regulate cycle timing and reduce bleeding. The right approach often depends on how and why your cycle has changed.

Lifestyle Support

The basics really do matter. Focusing on a few healthy lifestyle habits may make your cycle feel more manageable over time:

• Keep a consistent sleep schedule, even on weekends.
• Manage stress with whatever method works for you—like journaling, stretching, or deep breathing.
• Eat nutrient-packed meals with protein and complex carbs to support your activity level.
• Ease up on intense training if you’ve been pushing too hard.

Iron Repletion

If your iron is low from long or heavy periods, rebuilding it will be an important part of your treatment plan. Your doctor may recommend adding more iron-rich foods––like leafy greens, whole grains, and red meat––to your diet or taking an iron supplement. This can help address symptoms like fatigue, dizziness, and shortness of breath. 

Cycle Regulation 

When irregular ovulation causes longer gaps between periods or prolonged bleeding, hormonal medications can help. They provide a steady dose of hormones to regulate cycles and make periods more predictable. Common options include:

• a hormonal (levonorgestrel) IUD
• combined hormonal methods, like the pill, patch, or ring
• cyclic or continuous progestin therapy

Your clinician can help you choose the best method based on your symptoms, medical history, and fertility goals.

Condition-Specific Care

Sometimes a longer menstrual cycle is a sign of another health issue, and treatment needs to focus on the root cause. For instance, with PCOS or insulin resistance, healthy habits—like eating balanced meals and moving your body without overdoing it—can help balance hormones. A healthcare professional may also prescribe medications like metformin to improve cycle regularity.

Surgical or Procedural Options 

Surgery isn’t usually the go-to treatment for longer or irregular menstrual cycles. But your doctor might discuss surgical options if prolonged bleeding is severe or other treatments haven’t helped. Together, you can talk through the pros and cons of each option, based on your diagnosis, symptoms, preferences, and health and fertility goals.

• Polyp or fibroid removal: Removing polyps or fibroids through targeted procedures—like a polypectomy or myomectomy—can reduce heavy bleeding while leaving the uterus intact.
• Endometrial ablation: This procedure thins the uterine lining, which may make heavy periods lighter and more predictable. It’s usually only considered if you are done having children or don’t want any children.
• Hysterectomy: A hysterectomy to remove the uterus is a big step, and it’s generally reserved for situations where other treatments haven’t helped or heavy bleeding and other symptoms are taking a real toll on your well-being.  

Working with a Healthcare Professional 

Cycle changes aren’t always easy to explain, especially if you’re not exactly sure what’s changed. Is your menstrual cycle getting longer, your period lasting longer than usual, or both?

That’s why it helps to gather some key details before your first visit with a healthcare professional. Bring your cycle and symptom tracker, a list of your current medications and birth control, and the result of a pregnancy test (if you took one).

During the visit, ask what the likely cause of your cycle disruptions is and whether lab or imaging tests are recommended. Also talk about treatment options and when you should follow up. Make sure it’s clear what the next steps should be.

When to Seek Care 

Cycle changes can be frustrating, but they’re not always a sign that something is wrong. Still, some symptoms are worth getting checked out sooner rather than later. Get medical care if you notice any of the following:

• Very heavy bleeding that soaks through a pad or tampon every hour for 2 hours in a row.
• Large or frequent blood clots, especially if bleeding is hard to manage.
• Dizziness, fainting, or shortness of breath with heavy bleeding.
• Periods that regularly last longer than 8 days or cycles that go longer than 90 days apart (and you’re not pregnant or breastfeeding).
• Severe pelvic pain, fever, or foul-smelling vaginal discharge.
• Bleeding after sex or any bleeding after menopause (12 months without a period).
• A positive pregnancy test with bleeding or one-sided pelvic pain.

Key Takeaways

• A longer menstrual cycle usually means ovulation is delayed or skipped. This is common during perimenopause, when fluctuating estrogen and progesterone make cycle timing less predictable.
• “Longer cycle” and “longer period” are not the same thing. A longer cycle means more days between periods, while a longer period means bleeding lasts more days—and each has different causes.
• Perimenopause is the most common reason cycles lengthen with age. As menopause approaches, ovulation becomes irregular, often leading to longer gaps between periods.
• Stress, poor sleep, weight changes, and travel can also lengthen your cycle. High cortisol, circadian rhythm disruptions, and under-fueling can delay ovulation even outside of perimenopause.
• Cycles consistently longer than 38–40 days should be checked. Ongoing long cycles may be linked to thyroid issues, PCOS, medication changes, or other treatable conditions—and are worth discussing with a healthcare professional.

Frequently Asked Questions (FAQs)

Why is my menstrual cycle suddenly longer?

A longer menstrual cycle often means ovulation happened later than usual or didn’t happen at all that month. That can be triggered by hormone shifts during perimenopause, high stress, or poor sleep. Occasional longer cycles aren’t usually a cause for concern. But if it keeps happening, it’s worth tracking your cycles and checking in with a healthcare professional.

When should I worry about cycle length?

A little variation from month to month is typical. But if your cycles are consistently longer than 38 to 40 days—or you’re going 60 to 90 days between periods—it’s a good idea to track what’s happening and check in with a healthcare professional.

Does your menstrual cycle get longer as you age?

For many women, yes. As you approach perimenopause, ovulation can become less predictable, which often shows up as longer or more irregular cycles.

What does it mean if your period is lasting longer than usual?

Hormone shifts and physical changes in the uterus can make your period last longer than usual. Cycles without ovulation, which are more common in perimenopause, may cause longer bleeding. Fibroids or polyps, and even certain medications, can prolong your period. One-off changes happen, but it’s worth checking in with a doctor if prolonged bleeding persists or gets harder to manage.

Can a long period mean pregnancy?

Pregnancy usually causes a missed period, but sometimes early pregnancy—or early pregnancy loss—can look like a late or unusual period. If there’s any chance you could be pregnant, taking a test can help clear things up.