16 Jun

Leg cramps and restless leg syndrome can occur at any time, but usually occur at night and may effect up to 30% -50% of pregnant women, especially in the third trimester. 

In the majority of these women, cramps occur twice per week.

The cause of leg cramps in pregnancy remains unclear, although suggested reasons include metabolic disorders, inactivity or excessive activity, imbalances of electrolytes, vitamin deficiency or hyperactive lower motor neurons.

A Cochrane review found that there is currently no evidence on alternative therapies (massage, stretching, relaxation or heat), and insufficient evidence to determine whether any oral interventions (calcium, magnesium, vitamin B or C) are effective for leg cramps in pregnancy.

For some women, calcium, magnesium or vitamin B supplementation may be effective, but results are limited to small studies and are inconsistent.


Causes of leg cramps can include:  

  • Electrolyte imbalances
  • Dehydration
  • Inactivity or excessive exercise
  • Musculoskeletal problems e.g. prolonged sitting, back injuries, strenuous exercise of lower limbs, flat feet
  • Endocrine conditions e.g. thyroid disease, diabetes, renal damage leading to muscle cramping and weakness
  • Cardiovascular conditions e.g. history of deep vein thrombosis causing venous insufficiency
  • Neurological conditions e.g. multiple sclerosis, Huntington disease

Strategies for prevention or relief of cramps include: 

During leg cramps these things may help: 

  • Massage
  • Walking
  • Stretching  
  • Warm bath prior to bedtime
  • Balanced diet
  • Calcium gluconate supplements
  • Drinking adequate fluids
  • Prophylactic night-time calf stretching.

Taking Magnesium

Magnesium supplement 500mg (magnesium aspartate) tablets which contain equivalent magnesium of 37.4mg (1.55 mmol magnesium). 

Max one tablet daily.

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