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Menstrual Cycles: Is My Period Normal or Irregular?

Periods. They not only mark the end of a sentence, but they also mark the start of your menstrual cycle. 

From menarche (your first period) to menopause (when your period stops), your period will be a part of your life for many years. For some, this time of the month is no biggie, but for others, it can be filled with a range of period symptoms, some that are annoying and others that may be downright concerning. 

Just like no two people are alike, neither is your period. During the 3,000 days (give or take) you menstruate, it is normal to notice changes and there are several factors at play. 

To decide whether what you’re experiencing is normal or abnormal, a good place to start is to understand how it naturally can fluctuate during your lifetime. 

Read on to understand how your period will change over the years and five important menstrual period symptoms you should bring up with your health care provider.

How your menstrual cycle changes throughout your life

Your period in your pre-teen/teen years

In the U.S., the average age to start a period is around 12 years old. It may be irregular at first, with as many as six months passing between periods. One month, you get it at 21 days – the next, a no-show. It can make knowing the day of your next period difficult. 

Most cycles during early adolescence are between 21 days to 45 days. The good news is your cycle length should eventually level off somewhere between 21 days to 34 days (28 days on average) when you reach adulthood. 

Regardless of when they start their period, young women should make their first visit to the OBGYN between the ages of 13 and 15, according to the American College of Obstetricians and Gynecologists (ACOG). After that first visit, it’s typical for people with periods to start seeing a gynecologist or family provider regularly around 18 years old to maintain good reproductive health. Topics that may be discussed include birth control, safe sex and mental health.

Many young people in their teens and well into their 20s may start experiencing unpleasant symptoms of premenstrual syndrome (PMS), such as cramps and breast tenderness. 

Your period in your 20s 

In addition to symptoms of PMS, your 20s or even earlier is also the time when you may decide to begin hormonal contraception or birth control. Different birth control options can impact your menstrual cycle and period differently.  

“It can make your period shorter, lighter and more regular and reduce PMS symptoms,” said Heather Reed, MD, an OBGYN at Banner Health in Tucson, AZ. 

Your period in your 30s

For the most part, menstruation in your 30s should be pretty predictable and consistent at this point, although your PMS symptoms may worsen in your late 30s as you approach perimenopause. 

Another game-changer for your period that can occur during this time is pregnancy. Getting pregnant can stop your period. “Typically, your period won’t come back until about six weeks post-partum or longer if you’re breastfeeding,” Dr. Reed said.

Your period in your 40s

Many people in their 40s are also having children, so it’s not unusual to not have your period during this time. 

Your 40s is also when you begin perimenopausal hormonal changes. During this time, which can last 7 years to 14 years, your body prepares for your period to stop (menopause). 

“Your ovulation may be more irregular, you may experience a heavier flow or spotting between periods and longer stretches of PMS,” Dr. Reed said. “Just remember that you can still get pregnant, even when ovulation is erratic.”

Is my period normal? When to see your provider

Although your period can change over time, talk to your health care provider if you notice any of the following symptoms:

Severe pain. Cramps are a normal part of PMS. Typically, this causes mild pain that can be treated with heating pads and over-the-counter medications. However, if these normal interventions don’t work and your cycle is causing you to miss work or school, talk to your provider. 

“Constant pain could be a sign of uterine fibroids, adenomyosis or endometriosis, a condition where tissue similar to the lining of your uterus grows on other parts of your body,” Dr. Reed said. “Sharp pains could be a sign of an infection, such as a UTI (urinary tract infection), a ruptured ovarian cyst or an ectopic pregnancy.”

Heavy period. Although it may feel like you’re leaking gallons of blood, on average, you only lose three to four tablespoons of blood each cycle. Some people are lucky enough to have a light flow the whole time, while others have a heavy menstrual flow on the first day of their cycle and then again on day three or four. 

Let your provider know if your bleeding has become very heavy, where your pad or tampon is fully soaked through every hour for several hours in a row, or if your bleeding lasts longer than a week. A heavy flow could be a sign of something else, such as polyps, fibroids, a thyroid problem or von Willebrand disease.

No period or missed period. Before you run out for a home pregnancy test, consider what you have going on in your life at that time. It’s normal to skip periods from time to time. 

“You may notice after a stressful time in your life, a medical illness, breastfeeding, surgery, or after starting a new diet or fitness routine that your cycle is a little irregular,” Dr. Reed said. “Even using certain forms of birth control can affect your period. One skipped period shouldn’t be a cause for concern or worry.”

That said, if you have missed two or more periods in a row, talk to your provider. They can help rule out life changes and other causes of irregularity, such as polycystic ovary syndrome (PCOS), perimenopause or diabetes. 

Bleeding between periods. Spotting mid-cycle can happen from time to time. The most common cause for spotting is due to hormonal birth control, such as birth control pills, injections, patch and IUDs (intrauterine devices). 

Some people may also experience mild spotting when ovulation occurs or in the early stages of pregnancy when the fertilized egg attaches to the lining of the uterus.  

“Fluctuations in estrogen and progesterone during the time of ovulation can cause spotting mid-cycle,” Dr. Reed said. “Light spotting and bleeding, known as implantation bleeding, can also occur about 10 to 14 days after conception—when an egg is fertilized by sperm.”

Other potential causes could be due to a medical condition that needs to be addressed, such as an ectopic pregnancy, an infection of your reproductive organs, like chlamydia or gonorrhea, or cancer or a precancerous condition.

“If you start bleeding or spotting after menopause, you should see your provider as this can be a symptom of gynecologic cancer such as cervical or endometrial cancer,” Dr. Reed said.

Your period symptoms affect your daily functioning. Most people experience some degree of emotional and physical PMS symptoms before their period. But if you’re experiencing severe symptoms that affect your day-to-day life, it could be caused by a rare health condition known as premenstrual dysphoric disorder (PMDD).

“Someone with PMS might feel moodier or more sensitive, but PMDD causes more extreme behavioral and physical symptoms,” Dr. Reed said. “You may find yourself fighting with loved ones out of nowhere—even damaging relationships. May find it hard to concentrate and sleep.”

If you believe you have symptoms of PMDD, talk to your provider about treatment options that may help reduce or clear up your symptoms.


Periods can be unpredictable from time to time. If you have questions about your flow, don’t sweat it.

Have questions or concerns about your menstrual cycle?

Schedule an appointment with a primary care provider.
Schedule an appointment with a gynecologist.

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