WHO recommendation on interventions for the relief of leg cramps during pregnancy

WHO recommendation on interventions for the relief of leg cramps during pregnancy



Magnesium, calcium or non-pharmacological treatment options can be used for the relief of leg cramps in pregnancy, based on a woman’s preferences and available options.



Publication history

First published: November 2016

Updated: No update planned

Assessed as up-to-date: November 2016



  • The review found no evidence on the effect of non-pharmacological therapies, such as muscle stretching, relaxation, heat therapy, dorsiflexion of the foot and massage.
  • The evidence on magnesium and calcium is generally of low certainty. However, the GDG agreed that they are unlikely to be harmful in the dose schedules evaluated in included studies.
  • Further research into the etiology and prevalence of leg cramps in pregnancy, and the role (if any) of magnesium and calcium in symptom relief, is needed.



Women’s bodies undergo substantial changes during pregnancy, which are brought about by both hormonal and mechanical effects. These changes lead to a variety of common symptoms – including nausea and vomiting, low back and pelvic pain, heartburn, varicose veins, constipation and leg cramps – that in some women cause severe discomfort and negatively affects their pregnancy experience. In general, symptoms associated with mechanical effects, e.g. pelvic pain, heartburn and varicose veins, often worsen as pregnancy progresses. Leg cramps often occur at night and can be very painful, affecting sleep and daily activities (1)



The ANC recommendations are intended to inform the development of relevant health-care policies and clinical protocols. These recommendations were developed in accordance with the methods described in the WHO handbook for guideline development (2). In summary, the process included: identification of priority questions and outcomes, retrieval of evidence, assessment and synthesis of the evidence, formulation of recommendations, and planning for the implementation, dissemination, impact evaluation and updating of the guideline.

The quality of the scientific evidence underpinning the recommendations was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) (3) and Confidence in the Evidence from Reviews of Qualitative research (GRADE-CERQual) (4) approaches, for quantitative and qualitative evidence, respectively. Up-to-date systematic reviews were used to prepare evidence profiles for priority questions. The DECIDE (Developing and Evaluating Communication Strategies to support Informed Decisions and Practice based on Evidence) (5) framework, an evidence-to-decision tool that includes intervention effects, values, resources, equity, acceptability and feasibility criteria, was used to guide the formulation and approval of recommendations by the Guideline Development Group (GDG) – an international group of experts assembled for the purpose of developing this guideline – at three Technical Consultations between October 2015 and March 2016.

To ensure that each recommendation is correctly understood and applied in practice, the context of all context-specific recommendations is clearly stated within each recommendation, and the contributing experts provided additional remarks where needed.

In accordance with WHO guideline development standards, these recommendations will be reviewed and updated following the identification of new evidence, with major reviews and updates at least every five years.

Further information on procedures for developing this recommendation are available here.


Recommendation question

For this recommendation, we aimed to answer the following question:

  • For pregnant women (P), what interventions (pharmacological or non-pharmacological) for leg cramps (I) compared with no interventions (C) reduce morbidity and improve outcomes (O)?


Evidence summary

The evidence on the effects of various interventions for leg cramps in pregnancy is derived from a Cochrane review that included six small trials involving 390 pregnant women with leg cramps (1). Three studies from Norway (42 women), Sweden (69 women) and Thailand (86 women) contributed data on oral magnesium compared with placebo. One study from Sweden (43 women) compared oral calcium with no treatment; a study conducted in the Islamic Republic of Iran (42 women) compared oral vitamins B6 and B1 with no treatment; and another conducted in Sweden compared oral calcium with vitamin C (30 women). Symptom relief, measured in different ways, was the primary outcome in these studies, and other maternal and perinatal outcomes relevant to this guideline were not reported.

Oral magnesium versus placebo

In three small studies, women in the intervention group were given 300–360 mg magnesium per day in two or three divided doses. Studies measured persistence or occurrence of leg cramps in different ways, so results could not be pooled. Moderate-certainty evidence from the Thai study suggests that women receiving magnesium are more likely to experience a 50% reduction in the number of leg cramps (1 trial, 86 women; RR: 1.42, 95% CI: 1.09–1.86). The same direction of effect was found in the Swedish study, which reported the outcome “no leg cramps” after treatment, but the evidence was of low certainty (1 trial, 69 women; RR: 5.66, 95% CI: 1.35–23.68). Low-certainty evidence suggests that oral magnesium has little or no effect on the occurrence of potential side-effects, including nausea, diarrhoea, flatulence and bloating. Evidence from the third study was judged to be very uncertain.

Oral calcium versus no treatment

Calcium, 1 g twice daily for two weeks, was compared with no treatment in one small study. Low-certainty evidence suggests that women receiving calcium treatment are more likely to experience no leg cramps after treatment (43 women; RR: 8.59, 95% CI: 1.19–62.07). Oral calcium versus vitamin C Low-certainty evidence suggests that there may be little or no difference between calcium and vitamin C in the effect (if any) on complete symptom relief from leg cramps (RR: 1.33, 95% CI: 0.53–3.38).

Oral vitamin B1 and B6 versus no treatment

One study evaluated this comparison, with 21 women receiving vitamin B1 (100 mg) plus B6 (40 mg) once daily for two weeks and 21 women receiving no treatment; however, the low-certainty findings are contradictory and difficult to interpret.


Additional considerations

The review found no evidence on nonpharmacological therapies, such as muscle stretching, massage, relaxation, heat therapy and dorsiflexion of the foot.


Magnesium and calcium supplements are relatively low-cost interventions, particularly when administered for limited periods of two to four weeks.


The potential etiology of leg cramps being related to a nutritional deficiency (magnesium) suggests that the prevalence of leg cramps might be higher in disadvantaged populations. In theory, therefore, nutritional interventions may have equity implications, but evidence is needed.


Qualitative evidence from a diverse range of settings suggests that women generally appreciate the pregnancy-related advice given by healthcare professionals during ANC, so may respond to supplement suggestions favourably (moderate confidence in the evidence) (6). Evidence from some LMICs suggests that women hold the belief that pregnancy is a healthy condition and may turn to traditional healers and/or herbal remedies to treat these kinds of associated symptoms (high confidence in the evidence).


Qualitative evidence suggests that a lack of resources may limit the offer of treatment for this condition (high confidence in the evidence) (7). In addition, where there are additional costs for pregnant women associated with treatment, women are less likely to use it.


Further information and considerations related to this recommendation can be found in the WHO guidelines, available at:



Implementation considerations

  • The successful introduction of evidence-based policies related to antenatal care into national programmes and health care services depends on well-planned and participatory consensus-driven processes of adaptation and implementation. These processes may include the development or revision of national guidelines or protocols based on this recommendation.
  • The recommendation should be adapted into locally-appropriate documents and tools that are able to meet the specific needs of each country and health service. Modifications to the recommendation, where necessary, should be justified in an explicit and transparent manner.
  • An enabling environment should be created for the use of this recommendation, including changes in the behaviour of health care practitioners to enable the use of evidence-based practices.
  • Local professional societies may play important roles in this process and an all-inclusive and participatory process should be encouraged.
  • Antenatal care models with a minimum of eight contacts are recommended to reduce perinatal mortality and improve women’s experience of care. Taking this as a foundation, the GDG reviewed how ANC should be delivered in terms of both the timing and content of each of the ANC contacts, and arrived at a new model – the 2016 WHO ANC model – which replaces the previous four-visit focused ANC (FANC) model. For the purpose of developing this new ANC model, the ANC recommendations were mapped to the eight contacts based on the evidence supporting each recommendation and the optimal timing of delivery of the recommended interventions to achieve maximal impact.


Research implications

The GDG identified these priority questions related to this recommendation

  • What is the prevalence of common physiological symptoms among pregnant women in low-resource settings, and can the offer of treatment of these symptoms reduce health inequality, improve ANC coverage and improve women’s pregnancy experiences?
  • What is the etiology of leg cramps in pregnancy, and does treatment with magnesium and/or calcium relieve symptoms?



Related links

WHO recommendations on antenatal care for a positive pregnancy experience

(2016) - full document and evidence tables

Managing Complications in Pregnancy and Childbirth: A guide for midwives and doctors

Pregnancy, Childbirth, Postpartum and Newborn Care: A guide for essential practice

WHO Programmes: Sexual and Reproductive health

Maternal Health




  1. Zhou K, West HM, Zhang J, Xu L, Li W. Interventions for leg cramps in pregnancy. Cochrane Database Syst Rev. 2015;(8):CD010655.
  2. WHO handbook for guideline development, 2nd edition. Geneva: World Health Organization; 2014 (http://www.who.int/kms/handbook_2nd_ ed.pdf, accessed 6 October 2016).
  3. GRADE [website]. The GRADE Working Group; 2016 (http://gradeworkinggroup.org/, accessed 27 October 2016).
  4. GRADE-CERQual [website]. The GRADECERQual Project Group; 2016 (https://cerqual. org/, accessed 27 October 2016).
  5. The DECIDE Project; 2016 (http://www.decide-collaboration.eu/, accessed 27 October 2016).
  6. Downe S, Finlayson K, Tunçalp Ö, Gülmezoglu AM. Factors that influence the use of routine antenatal services by pregnant women: a qualitative evidence synthesis. Cochrane Database Syst Rev. 2016;(10):CD012392
  7. Downe S, Finlayson K, Tunçalp Ö, Gülmezoglu AM. Factors that influence the provision of good quality routine antenatal care services by health staff: a qualitative evidence synthesis. Cochrane Database Syst Rev. 2016


Citation: WHO Reproductive Health Library. WHO recommendation on interventions for the relief of leg cramps during pregnancy. (November 2016). The WHO Reproductive Health Library; Geneva: World Health Organization.