Why Period Cramps Make You Feel Faint and What to Do

Feeling faint during severe period cramps is often linked to vasovagal syncope, a response to pain and other bodily changes during your cycle that cause sudden drops in blood pressure. Solutions like staying hydrated, managing pain, and getting enough iron can help reduce these episodes.

Why You Feel Like You’re Going to Pass Out

Vasovagal syncope is the most common type of fainting, caused by a sudden drop in blood pressure. During your period, factors like hormonal fluctuations, pain, heavy bleeding, and low blood sugar may increase this risk.

Vasovagal syncope affects both your nervous and cardiac systems. Your nervous system sends signals to control heart rate and other functions, with the vagus nerve playing a key role. Certain triggers can cause it to signal a rapid decrease in heart rate and blood pressure, which reduces blood flow to the brain and may result in fainting.

These changes can cause symptoms such as:

Recognizing the warning signs might help you avoid fainting from a vasovagal reaction, but symptoms can sometimes appear too fast to prevent it.

What Causes Severe Period Cramps?

Pain can trigger vasovagal syncope, including pain from menstrual cramps. Period pain may cause bodily changes that increase fainting risk. 

Primary dysmenorrhea, or painful periods without an underlying cause, are linked to a hormone called prostaglandin. This hormone, produced in the endometrium (uterus lining), increases just before and during your period.

Prostaglandins can help manage pain by widening blood vessels, a process known as vasodilation.

When blood vessels widen, blood pressure can drop, setting the stage for a heightened vagal response and an increased risk of fainting due to menstrual cramp pain.

Fibroids

Uterine fibroids, or leiomyomas, are non-cancerous tumors in the uterus that can cause painful periods. They may also lead to heavy bleeding, bloating, bathroom issues, pain during intercourse, infertility, and miscarriage. Many people with uteruses have fibroids, but Black people are three times as likely to develop them compared to 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.

Why Is My Period So Heavy?

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

How Hormonal Changes Cause Faintness

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.