Last updated: June 2026
During pregnancy, health takes on a whole new level of importance — for both mother and baby. Magnesium is one of the most important minerals involved in pregnancy, yet deficiency is surprisingly common. Here’s everything you need to know.
Can you take magnesium while pregnant?
Yes — pregnant people can take magnesium supplements, and in many cases it’s actively recommended. Hormonal changes during pregnancy make expectant mothers more susceptible to magnesium deficiency: on average, pregnant women lose 20–25% of their magnesium through the kidneys, while both mother and foetus require the mineral.
Research has found that the mean dietary magnesium intake of pregnant women falls between 35–58% of the recommended dietary allowance — well below adequate levels. A published study on magnesium in pregnancy and fetal programming concluded that magnesium deficiency during gestation may interfere with fetal growth, favour premature labour, and even increase the baby’s risk of health conditions in adulthood.
Always consult your midwife or GP before starting any supplement during pregnancy.
Symptoms of low magnesium in pregnancy
Low magnesium in pregnancy can manifest in many ways that overlap with other pregnancy symptoms — making it easy to miss:
- Headaches
- Leg cramps (particularly at night)
- Anxiety and low mood
- High blood pressure
- Constipation
- Nausea and vomiting
- Restless legs
- Difficulty sleeping
Notably, fluctuating hormones can alter magnesium levels and contribute to morning sickness — magnesium plays a role in balancing cortisol and regulating blood sugar, and blood sugar changes are thought to be a driver of pregnancy nausea.
Looking for magnesium supplements for adult wellbeing?
Take our free quiz and we’ll match you with the right Evopure formula. Always consult your GP or midwife before taking any supplement during pregnancy.
Take the free health quiz →Benefits of magnesium during pregnancy
Reduced physical discomfort
Leg cramps, restless leg syndrome, headaches, insomnia and constipation are all common pregnancy symptoms that may be alleviated by addressing magnesium deficiency. Read more: Magnesium for sleep
Emotional support
Pregnancy is an emotional experience even when joyful. Hormonal fluctuations commonly manifest as anxiety, irritability and low mood — and magnesium is linked to emotional regulation. A clinical trial found that 248 mg of magnesium daily led to significant reductions in depression and anxiety symptoms compared to placebo. This was in a general population context, but the mechanism is relevant to pregnancy-related emotional vulnerability.
Reduced risk of complications
Research has linked low serum magnesium levels in pregnant women with higher rates of preterm labour and preterm birth. Women supplementing magnesium throughout pregnancy may also be less likely to develop high blood pressure, uterine irritability, preeclampsia or eclampsia. One study found that a magnesium-containing multi-mineral supplement resulted in fewer pregnancy complications than two control groups.
Always consult a clinician who can advise on the correct type and dosage for your specific situation.
Side effects of magnesium in pregnancy
Magnesium is generally safe and well-tolerated. However, excess intake may cause: nausea, vomiting, diarrhoea, urine retention and lethargy as the body eliminates surplus magnesium. Always stick to recommended dosage guidelines and check in regularly with your midwife or GP.
How much magnesium is safe during pregnancy?
The commonly cited recommended daily dose during pregnancy is 350–360 mg/day. Around 500 mg/day is considered too high for a pregnant person. The UK government drug safety guidelines note that maternal administration of magnesium sulfate for longer than 5–7 days may be associated with adverse effects on the foetus — however, this warning relates to intravenous magnesium sulfate administered in medical settings, not typical oral supplement use at the doses discussed here.
Magnesium is also safe to continue while breastfeeding after delivery.
Read more: How long does magnesium stay in your body?
What happens if you take too much magnesium during pregnancy?
Excessive oral magnesium leads to the side effects described above as the body eliminates the surplus. Always stay within recommended dosage and never exceed 500 mg/day during pregnancy. Regular check-ins with a health professional are particularly important during pregnancy — they can monitor magnesium levels and adjust dosage for mother and baby’s needs.
Frequently asked questions
Can you take magnesium while pregnant?
Yes — and in many cases it’s recommended given the high prevalence of deficiency. Always consult your midwife or GP first.
What are signs of low magnesium in pregnancy?
Leg cramps, headaches, anxiety, low mood, high blood pressure, constipation, nausea and insomnia can all indicate deficiency — though these overlap with other pregnancy symptoms. Seek clinical assessment.
How much magnesium is safe during pregnancy?
350–360 mg/day is the commonly recommended range. Around 500 mg/day is considered too high. Always follow your clinician’s guidance.
Is the magnesium sulfate warning relevant to oral supplements?
No — the UK warning relates to prolonged intravenous magnesium sulfate in medical settings, not daily oral supplementation at the doses discussed here.
Is magnesium safe while breastfeeding?
Yes — magnesium is considered safe to continue while breastfeeding after delivery.
Looking for magnesium for adult wellbeing?
Take our free quiz to find the right Evopure formula for stress, sleep or energy. Always consult a clinician before taking supplements during pregnancy.
Take the free health quiz →Final thoughts on magnesium in pregnancy
Magnesium supplementation during pregnancy can support both mother and baby — replacing minerals lost through excretion, reducing common discomforts, supporting emotional balance and potentially lowering the risk of complications. The evidence base is strong. Always discuss supplementation with your midwife or GP, stay within recommended dosage ranges, and consult on the appropriate form of magnesium for your specific needs.
