Leg cramps during pregnancy

Cramps are involuntary muscle spasms caused by a buildup of acids. They usually last 30 to 60 seconds. More than half of all pregnant women get leg cramps. Some women also experience cramps in their buttocks and thighs. These muscle contractions often occur at night, especially during the second and third trimesters.

Causes

Many different factors can cause cramps during pregnancy:

• The increased weight of the uterus, which puts greater pressure on the abdominal nerves and blood vessels
• Fatigue
• A mineral imbalance in the blood or a vitamin deficiency (e.g., a lack of calcium, phosphorus, vitamin D, or vitamin E)
• Dehydration
• Too little or too much exercise
• Poor blood circulation due to increased blood volume and the pressure of the uterus on the blood vessels
• Muscle tension in the toes

Prevention

Here are a few tips to help you prevent muscle cramps:

• Maintain a balanced diet. For example, eat foods rich in calcium (milk, cheese, yogurt) and magnesium (legumes, nuts, spinach, Swiss chard, seeds, dark chocolate).
• Drink plenty of fluids to stay hydrated (i.e., 1.5–2 litres per day). Increase your fluid intake in extreme heat.
• Don’t overexert yourself, and rest whenever you have the chance.
• Wear shoes with flat heels.
• Wear compression stockings to improve circulation.
• Place your feet and legs in an elevated position several times a day.
• Exercise every day, such as by going for walks.
• Do one of the following calf stretches before bed:
  – Sit with your legs uncrossed. Lift your right leg, bending your knee at 90 degrees, and pull your toes toward you while flexing your heel forward. Repeat with the left leg.
  – Stand facing a wall. Place your hands on the wall and position your right leg behind your left foot. Gently bend your left leg forward, keeping your right leg in extension and your right heel on the floor. Hold this position for about 30 seconds. Repeat with your left leg behind your right foot.
  – Do a few repetitions of these exercises.
• Apply heat to your calves or take a warm bath before going to bed.

Pain relief

If you get a leg cramp, there are a few things you can do to reduce your discomfort:

• Extend your leg.
• Stretch your calf muscle by flexing your foot upward to avoid pointing your toes. You can also try standing up, making sure to keep your foot flat, or standing on a cold surface.
• Massage and apply heat to the affected muscle.
• Take a hot shower or bath.
• Walk around or elevate your legs to prevent the cramp from returning.

If you get a severe cramp, your calf may be tender the next morning. If the pain persists for several hours, applying heat may help, especially before exercising. The pain should fade with time, much like muscle pain from a hard workout.

When should you see a doctor?

In rare cases, thrombosis can occur if a blood clot forms in the deep veins of the leg. This condition needs to be treated promptly. You should see a health care professional as soon as possible in the following situations:

• You experience intense leg pain that is not a cramp
• Your leg or foot is swollen
• Your skin turns very pale or bluish

You should also see your doctor if your leg pain persists, if you notice any redness or swelling, or if you experience numbness in your leg.

Things to keep in mind

• Leg cramps are caused by involuntary muscle spasms.
• Eating a balanced diet, staying hydrated, and exercising can help prevent cramps.
• Calf stretches can relieve pain when a cramp occurs.

Scientific review: Lise Ross, M.Sc., nurse, CHUM Birthing Centre Research and copywriting: The Naître et grandir team Updated: May 2020