Painful Menstruation (Dysmenorrhea): Causes and Relief

What period pain feels like

Typical period pain is a cramping, aching or throbbing pain in the lower belly, starting a few hours to a day before bleeding and lasting 1 to 3 days. It may spread to the lower back and the inner thighs. Many people also have:

• nausea, vomiting or loose stools
• headache
• tiredness and dizziness
• bloating

Why periods hurt

During a period, the uterine lining releases prostaglandins. These make the uterine muscle contract to shed the lining, and in high amounts cause strong contractions that briefly cut off blood flow to the muscle, which hurts in the same way as a cramp elsewhere. Prostaglandins also cause the nausea and diarrhea. People with more prostaglandins have more painful periods. This explains why NSAIDs, which block prostaglandin production, work so well.

Primary vs secondary dysmenorrhea

Causes of secondary dysmenorrhea

• Endometriosis: tissue similar to the uterine lining grows outside the uterus. It causes severe period pain, pain with sex, painful bowel movements or urination during periods, chronic pelvic pain and difficulty conceiving. It often starts in the teens and takes years to diagnose. Period pain severe enough to miss school is a common early sign.
• Adenomyosis: lining tissue inside the uterine muscle, causing heavy, painful periods, usually in the 30s and 40s.
• Uterine fibroids: can cause heavy, painful periods and pressure.
• Pelvic inflammatory disease: infection of the uterus and tubes, usually from chlamydia or gonorrhea, causing pain, fever, discharge and painful sex.
• Copper IUD: can increase cramps, especially in the first months.
• Ovarian cysts, cervical stenosis (a narrowed cervix) and congenital uterine abnormalities.

How the cause is found

A doctor will ask when the pain started, how it affects your life, its pattern and severity, bleeding, pain with sex or bowel movements, and contraception. A pain diary and a 0 to 10 pain score help. For teens with typical primary dysmenorrhea, an examination may not be needed before trying treatment.

Tests for secondary causes may include:

• sexually transmitted infection testing and a pregnancy test
• pelvic exam
• transvaginal or abdominal ultrasound for fibroids, adenomyosis and cysts
• MRI in some cases
• laparoscopy (keyhole surgery), which can confirm and treat endometriosis

Treatment and relief

Medicines

• NSAIDs: ibuprofen, naproxen or mefenamic acid are the first choice. Start at the first sign of the period or pain, or a day before if your cycle is predictable, and take regularly for 2 to 3 days rather than waiting until pain is severe. Follow the label dose. Avoid if you have stomach ulcers, kidney disease, NSAID-sensitive asthma, or are pregnant.
• Acetaminophen (paracetamol) helps less but is an option if you cannot take NSAIDs.
• Hormonal birth control: the combined pill, patch or ring, the hormonal IUD, the implant and the injection reduce or stop period pain for most people. The pill can be taken continuously to skip periods.

Home measures

• Heat: a heating pad or hot water bottle on the lower belly is about as effective as an NSAID for some people.
• Exercise: regular aerobic activity reduces period pain over time.
• TENS machines: a small device that sends mild electrical pulses through the skin can reduce pain.
• Rest, warm baths, and gentle stretching or yoga.
• Stop smoking: smokers have more painful periods.

Treating the cause

Secondary dysmenorrhea is treated by addressing the condition: hormonal treatments or surgery for endometriosis and adenomyosis, fibroid treatments, antibiotics for pelvic infection, or removing a copper IUD.

Frequently asked questions

What is the difference between primary and secondary dysmenorrhea?

Primary dysmenorrhea is common period pain caused by prostaglandins, with no underlying disease, usually beginning in the teens. Secondary dysmenorrhea is caused by a condition such as endometriosis, adenomyosis, fibroids or infection, and often starts later or worsens over time.

When is period pain not normal?

Period pain is not normal if it stops you from going to school or work, does not improve with NSAIDs or hormonal contraception, worsens over the years, starts after 25, or comes with heavy bleeding, pain during sex or bowel movements, or bleeding between periods.

What is the fastest way to relieve period cramps?

Take an NSAID such as ibuprofen or naproxen at the first sign of pain, following the label dose, and apply heat to your lower belly. Gentle movement and a warm bath help. Taking the NSAID early works better than waiting until the pain is severe.

Can period pain be a sign of endometriosis?

Yes. Severe period pain, especially with pain during sex, painful bowel movements during periods, chronic pelvic pain or difficulty getting pregnant, is a common sign of endometriosis. It is often missed for years, so ask your doctor about it if your pain is severe.

Does period pain get better with age?

Primary dysmenorrhea often eases in the mid-20s and after childbirth. Pain that gets worse with age suggests a secondary cause such as endometriosis, adenomyosis or fibroids and should be evaluated.