How Many Days Should a Period Last?

Just as no two women are exactly the same, no two menstrual cycles are the same. But there are some guidelines when it comes to the length of your periods and other factors, like flow and frequency.

At the private practice of OB/GYN Kelly Morales, MD, we diagnose and treat abnormal periods, including periods that are too long, too heavy, or infrequent. Keep reading to learn more about the typical length of periods and the signs that it’s time to seek medical help.

How long should my period last? 

Before considering whether your period is too long or too short, you need to understand how doctors think about normal periods. What’s normal for one woman might be unusual for another, making it more difficult to know when something’s wrong.

On average, we consider normal menstrual cycles to last 21-35 days, and normal periods to last as few as three days or as long as seven days. With such a wide range of what’s considered normal, we also take into account what has been normal for you historically. 

It’s time to schedule an exam with Dr. Morales if your periods are:

• Typically very long (more than seven days)

• Very short (less than three days)

• Accompanied by other symptoms that could indicate an underlying condition, such as severe pain or bleeding between your periods

What can I do if my period is too long or too short? 

Many different conditions can cause long or short periods, making it even more important to see Dr. Morales for an expert diagnosis. Here’s a look at some of the most common causes of long and short periods:

Very long periods

If your periods last longer than a week, schedule an appointment, since long periods can be the result of a wide range of conditions, including:

• Polycystic ovarian syndrome (PCOS)

• Injury or infection

• Changes in hormones or ovulation

• Certain medications (e.g., IUDs, contraceptives, blood thinners)

• Pregnancy

• Endometriosis or adenomyosis

• Uterine fibroids or polyps

• Hypothyroidism

• Pelvic inflammatory disease

• Certain cancers

• Obesity 

Dr. Morales reviews your medical history, conducts a physical exam, and may order lab work or imaging, like an ultrasound, to get to the root cause. Depending on what she determines, treatment may involve birth control, hormone replacement therapy, minimally invasive procedures like ablation, or surgery.

Very short periods

While very short periods, those lasting a day or two, may sound like a dream to some women, they could be the sign of an underlying health condition, especially if your cycle suddenly becomes shorter.

As with long periods, there are many possible causes of very short periods. Some reasons women experience very short periods include:

• Pregnancy, which can cause spotting or light bleeding a week or two after fertilization

• Miscarriage, which can start with light spotting that may be mistaken for a period

• Perimenopause

• Anovulation (your ovaries do not release an egg)

• PCOS

• Endometriosis 

• Certain types of birth control

While one short period probably isn’t cause for concern, contact Dr. Morales if your period becomes short after being regular or if you experience other symptoms with a short period, like heavy bleeding or skipping several periods. 

To learn more about normal menstrual cycles or for help with long or short periods, schedule an appointment today with Dr. Morales in San Antonio, Texas.