Nighttime leg cramps are a discomfort that can seriously disrupt daily life, and for pregnant women, they often become a painful routine. It is estimated that this problem affects 30 to even 45% of pregnant women, intensifying especially in the second half of pregnancy. The pain is sudden and sharp, usually targeting the calf muscles, waking women from sleep and preventing the rest that is so crucial during this period. Although medicine has long recognized this problem, until now there has been no standard, fully effective treatment, and research results on popular magnesium supplements have been inconsistent: some confirmed its efficacy, while others suggested it was ineffective. However, the latest studies conducted by researchers in Bangkok shed new light on the topic, offering hope for a restful sleep to many expectant mothers.
The researchers’ starting point was human physiology. Magnesium is the second most important cation inside our cells and participates in over 300 metabolic reactions. During pregnancy, blood levels of this element naturally decrease, which can lead to neuromuscular hyperexcitability and painful cramps. To finally determine whether supplementation makes sense, a team of doctors from the Faculty of Medicine at Chulalongkorn University conducted a rigorous clinical trial involving 86 healthy women between the 14th and 34th week of pregnancy who reported leg cramps at least twice a week. The study was double-blind, meaning that neither the patients nor the doctors administering the treatments knew who received the real supplement and who received a placebo.
A key factor in the success of this experiment may have been the type of supplement used. Previous studies that showed no efficacy of magnesium used magnesium lactate or citrate. In this study, the researchers used magnesium bisglycinate chelate at a dose of 300 mg daily for 4 weeks. This choice was not accidental – this particular chemical form of magnesium has an absorption rate more than twice that of the previously mentioned compounds, which could explain the therapeutic success. Participants recorded the frequency and severity of their cramps using a specialized 100-mm visual analog scale, both before starting treatment and after 4 weeks.
The results were clear and very promising. After 1 month of treatment, the magnesium group showed significantly greater improvement than the placebo group. As many as 86% of women taking magnesium experienced a 50% reduction in cramp frequency, compared to 60.5% in the placebo group. Moreover, supplementation affected not only the frequency of pain but also its severity. Nearly 70% of women in the treatment group reported a significant reduction in pain intensity, compared to just under 49% in the control group. The most striking result, however, was that in the magnesium chelate group, almost half of the women (48.8%) completely eliminated leg cramps by the end of the treatment, a much better outcome than in the placebo group.
It is worth noting that the therapy was safe. Concerns about side effects such as nausea or diarrhea, which often accompany mineral supplementation, were not confirmed in the statistics – these symptoms occurred equally rarely in both groups, suggesting that the tested supplement was well tolerated. Researchers emphasize that the therapy’s success was likely due to a combination of two factors: the use of a highly bioavailable magnesium chelate and a sufficiently long 4-week treatment period. These results send a clear signal that oral magnesium supplementation, specifically magnesium bisglycinate, can be an effective and safe option for treating troublesome leg cramps during pregnancy, significantly improving the quality of life and sleep of expectant mothers.
Reference: Supakatisant C, Phupong V. Oral magnesium for relief in pregnancy-induced leg cramps: a randomised controlled trial. Matern Child Nutr. 2015 Apr;11(2):139-45.
