Severe Period Cramps: Why You Feel Faint and in Pain

Some people feel lightheaded or experience fainting episodes during their period. If you feel period cramps so badly you almost pass out, then you may also be concerned that it's a sign of a serious issue rather than a common experience.

Your body undergoes many changes during a normal menstrual cycle. Sometimes these changes can heighten certain responses in your body that increase your risk of fainting during your period.

This article explains the medical reasons why people faint from any cause. It also discusses the specific reasons why that may happen during your period and what you can do about it.

Why You Feel Like You’re Going to Pass Out

Vasovagal syncope is the most common type of fainting and is characterized as a sudden drop in blood pressure, leading to fainting. During your period, changes in your body, such as hormonal fluctuations, pain, heavy menstrual bleeding, and low blood sugar, may increase your chance of fainting.

Vasovagal syncope involves both your nervous and cardiac systems. The nervous system is always sending signals that control heart rate and other vital functions in your body. One of those nerves is the vagus. Certain things can trigger a reflex in which the vagus nerve sends signals that cause heart rate and blood pressure to drop quickly. This can cause decreased blood flow to your brain and lead to fainting.

As these changes are happening, they cause common symptoms that may include:

• Nausea
• Sweating
• Lightheadedness
• Blurred vision
• Rapid or irregular heartbeat
• A sense of numbness (paresthesia)
• Pallor, or looking pale

If you know the warning signs, you can try to avoid fainting because of a vasovagal response. But sometimes, these symptoms come on too fast, and you can't stop yourself from fainting.

Painful Periods

Pain, in general, is a known trigger for vasovagal syncope. Just like other forms of pain, your response to period pain can cause changes in your body that lead you to faint. But there might be something specific about period pain that increases your chance of fainting.

Primary dysmenorrhea, or a painful period with no underlying cause, is related to a hormone called prostaglandin. It's produced in the endometrium, the lining of your uterus, during the later part of your menstrual cycle, right before and as your period starts.

Painful periods may cause your body to make more prostaglandin, which your body needs to manage pain, illness, and injury. One of these responses will cause your blood vessels to open wider, a process known as vasodilation.

Your blood pressure can drop when your blood vessels are wider. This may set the stage for a heightened vagal response, and a higher risk of fainting due to the pain caused by menstrual cramps.

Fibroids

Uterine fibroids, also known as leiomyomas, are non-cancerous tumors that grow in the uterus and can lead to painful periods. In addition to pain, fibroids can cause heavy or long-lasting menstrual bleeding, bloating, trouble going to the bathroom, pain during intercourse, infertility, and miscarriage. Many people with uteruses experience fibroids, but Black people are three times as likely to develop fibroids as white people.

There are many possible treatment options for fibroids, including:

• Uterine fibroid embolization: A procedure in which tiny particles are placed in the arteries that supply blood to the fibroid, depleting their blood supply and causing it to shrink
• Myomectomy: A surgical procedure to remove a fibroid while preserving uterus function
• Hysterectomy: The surgical removal of the uterus along with all its fibroids

Endometriosis

Endometriosis is a condition where tissue that lines the uterus (the endometrium) grows outside of the uterus. Endometrial tissue might grow almost anywhere in the body but is more commonly found on the ovaries, fallopian tubes, bowel, kidneys, and liver. It can cause debilitating symptoms and severe pain. The only way to definitively diagnose endometriosis is a surgical procedure where tissue outside the uterus is collected and analyzed to see if it is endometrial tissue.

While there is no cure for endometriosis, some treatments include:

• Medication to control pain
• Oral contraceptives
• Surgical removal of endometrial tissue
• Gonadotropin-releasing hormone (GnRH) agonists

Adenomyosis

Adenomyosis is a potentially painful condition in which the lining of the uterus (the endometrium) grows into the muscular walls of the uterus. Although most women with adenomyosis are in their 40s and 50s, younger women are being diagnosed at higher rates. It is diagnosed with a clinical history of symptoms and can be detected with ultrasound and MRI.

Treatment for adenomyosis includes:

• Oral contraceptives
• Hormone-containing IUD
• Hysterectomy

Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome is characterized by an array of clinical symptoms, including higher-than-average levels of androgens and other hormonal imbalances, enlarged ovaries prone to developing cysts, resistance to insulin, and being overweight. Not every person with PCOS will necessarily experience all of these symptoms.

PCOS is associated with painful periods, although the exact cause is somewhat unclear. Some research suggests it may be due to the general hormonal imbalances typically seen in people with PCOS.

Treatment for PCOS can include lifestyle changes, oral contraceptives, and other medications to help with hormones.

Heavy Periods

Often, a heavier menstrual flow is associated with more build-up of the endometrial lining in your uterus during your menstrual cycle. This may lead to more prostaglandin production—which, as noted above, might also increase the chances of a fainting episode.

Heavy periods also can lead to blood loss that causes anemia. When you are anemic, the amount of oxygen that your blood can carry is lower. When your brain senses even the slightest drop in oxygen levels, it triggers the changes that may lead to fainting.

The amount of flow in a period is relative, however, there are some guidelines. Your period is considered heavy if you meet one or more of the following criteria:

• You need to change your pad or tampon every hour.
• You need to double up on menstrual products to prevent leaking.
• You have to get up at night to change your menstrual product.
• You pass clots larger than a quarter.

There are many factors that can cause heavy menstrual bleeding, also called menorrhagia. Some people simply have a more heavy period based on their own genetics and predisposition. Other reasons periods can become heavy include:

• Fibroids
• Polyps
• Adenomyosis
• Cancer
• Endometriosis
• Blood disorders
• Using a copper IUD
• Blood-thinning medications

Hormonal Changes

Changes in hormone levels are the basis of your menstrual cycle. If you have regular cycles, the estrogen and progesterone levels in your body change in typical ways across the cycle. During the start of your period, these hormone levels are at their lowest.

Hypoglycemia

In some people, these hormonal shifts can cause changes in insulin sensitivity that can lead to episodes of relatively low blood sugar called hypoglycemia. These episodes can happen even if you do not have diabetes. Low blood sugar levels also may lead to a vasovagal response that causes you to faint.

Fluid Shifts

Another cause of fainting episodes is linked to fluid shifts in your body. The low hormonal levels during a period may cause more fluid to move from the bloodstream and into body tissues. This may cause edema, or swelling, of the legs and ankles. It also means there is less blood volume circulating oxygen throughout your body.

Your body reacts to this much as it does to dehydration. Because the amount of fluid in your bloodstream is less, your body can't adjust as well to changes in position. This may cause a drop in blood pressure when you stand or move, called orthostatic hypotension, which can lead to fainting.

POTS

Fluid shifts caused by hormone changes can also aggravate a specific condition in young adults called postural orthostatic tachycardia syndrome (POTS). This disorder disrupts the nervous system's normal ability to control heart rate and blood pressure, with symptoms that worsen during your period.

Symptoms of POTS include fatigue, dizziness, and frequent fainting.

Summary

Some people do experience fainting spells during their periods. In many cases, hormonal changes in the body during your period may be part of the reason. These can lead to lower blood pressure, less blood volume, lower blood sugar, anemia, and a more sensitive vagal response.

All of these can lead to fainting. In most cases, though, these episodes are not caused by a serious medical condition. Simple diet and lifestyle changes, along with taking the right pain medication, can often prevent fainting.