Lower back pain on your period: why it happens and what helps

What period back pain feels like

For some people, period pain lives mostly in the back rather than the tummy. It's usually a deep, dull ache across the lower back or just above the buttocks, sometimes with waves that match the cramps in front. It can spread into the hips and down the thighs.

• A dull, heavy ache in the lower back, on both sides or in the middle
• Pain that comes and goes in waves with period cramps
• Aching that spreads into the hips, buttocks or legs
• Worse when you've been sitting or standing still for a long time
• Starting a day or two before bleeding and easing by day 2 or 3

Why your back hurts on your period

Referred pain from the uterus

As your period starts, the uterine lining releases prostaglandins, which make the muscle of the uterus contract. Pain signals from the uterus travel along nerves that enter the spinal cord at the same levels as nerves from the lower back. The brain can't always tell exactly where the pain is coming from, so you feel it in your back. That's called referred pain.

Other contributors

• Prostaglandins themselves increase general sensitivity to pain and inflammation.
• Bloating and fluid in the days before your period change how you hold yourself.
• Tension and poor sleep tighten the muscles around your hips and back.
• Position of the uterus: some people with a tilted (retroverted) uterus notice more back pain, though this varies.

What helps period back pain

1. Heat on your lower back. A stick-on heat patch under your clothes works well during the day; a hot water bottle or warm bath in the evening.
2. An anti-inflammatory, taken early. Ibuprofen or naproxen reduce prostaglandins, so they work best at the first sign of pain. Check with a pharmacist if they're right for you.
3. Move gently. Walking, swimming or cycling ease back pain more than lying still. Regular exercise across the month is linked with less period pain overall.
4. Stretch. Child's pose, cat-cow, knees-to-chest and gentle pelvic tilts release the lower back and hips.
5. Massage. Firm pressure on the lower back, or rolling on a ball against a wall, can help a lot.
6. Change position often. Avoid sitting still for long stretches on day 1. Lying on your side with a pillow between your knees can help at night.
7. TENS. A small TENS machine on the lower back helps some people with period pain.

When back pain points to something else

Back pain that gets worse every cycle, starts well before your period, or continues after it can be a sign of endometriosis or adenomyosis, where tissue similar to the uterine lining grows outside the uterus or into its muscle. Large fibroids can press on the back. Pelvic inflammatory disease can also cause lower back pain with fever and unusual discharge. And sometimes back pain has nothing to do with your period at all, such as a muscle strain, a kidney problem or a urinary infection.

Pain and mood

A nagging ache is exhausting. It makes it harder to concentrate, sleep and stay patient, so it's no surprise that painful period days often feel like low mood days. Treating pain early is also a way of looking after your mood. Read about mood during your period.