Is Magnesium Safe To Take if You're Pregnant?

Magnesium is one of the seven essential minerals your body needs for hundreds of vital processes.
During pregnancy, this mineral becomes even more important—it supports your nerves, muscles, bones, and heart while helping your baby develop strong bones and a healthy metabolism.

Yet, magnesium deficiency is surprisingly common among pregnant people. Understanding how magnesium works, the best food sources, and whether supplements are safe can help you make informed choices for a healthier pregnancy.

Why Magnesium Matters During Pregnancy

Magnesium plays a crucial role in both maternal and fetal health.
It supports:

• Muscle and nerve function – helping your uterus and body relax naturally.

• Bone health – essential for the baby’s skeletal development.

• Energy production – assisting in the conversion of food into energy.

• Blood pressure regulation – keeping preeclampsia risk lower.

• Blood sugar control – improving glucose metabolism to prevent gestational diabetes.

Because pregnancy increases metabolic demand, your body needs slightly more magnesium—about 10 % higher than usual.

For most adults, the recommended daily allowance (RDA) is:

Can You Take Magnesium While Pregnant?

Research is still evolving, but current evidence suggests that magnesium supplements are safe in moderate doses when prescribed by a healthcare professional.

Because many people consume less than the required amount through food, supplements may be necessary to fill nutritional gaps—especially for those with morning sickness, food aversions, or dietary restrictions.

The safe upper intake level (UL) for magnesium from supplements during pregnancy is generally 350–400 mg per day, depending on your age.

Always check with your OB-GYN or midwife before starting supplementation, since excessive intake can lead to side effects such as diarrhea or nausea.

Signs of Magnesium Deficiency in Pregnancy

Deficiency can affect both the pregnant person and the developing baby.
Common signs include:

• Muscle cramps or twitching

• Fatigue or weakness

• Headaches or migraines

• Irritability or mood swings

• Trouble sleeping

• Irregular heartbeat

A 2019 review found that up to 80 % of pregnant women consume less than 300 mg/day, mostly due to poor diet and nausea in early pregnancy.

Addressing magnesium deficiency can help reduce discomfort and prevent complications such as preeclampsia and preterm labor.

Benefits of Magnesium During Pregnancy

1. Helps Prevent High Blood Pressure

Magnesium supports blood-vessel relaxation and helps regulate pressure inside the arteries.
Low magnesium levels are linked to preeclampsia, a pregnancy complication characterized by high blood pressure and organ stress.

Several studies show that magnesium supplementation can lower the risk of preeclampsia when taken consistently under medical supervision.

2. Relieves Leg Cramps

Leg cramps are common during pregnancy, especially at night.
Magnesium assists in muscle relaxation, reducing cramps and spasms.

A 2022 study found that taking 200–360 mg of magnesium daily significantly decreased both the frequency and intensity of leg cramps among pregnant participants.

3. Lowers Risk of Cerebral Palsy in Preterm Infants

For pregnant people at risk of preterm delivery, magnesium sulfate given intravenously may protect the baby’s brain and reduce the risk of cerebral palsy.

This treatment is typically administered in hospitals and monitored carefully by healthcare professionals.

4. Improves Sleep Quality

Magnesium helps activate the body’s natural relaxation system by influencing GABA receptors, which calm the nervous system.
This may lead to better sleep and less fatigue, both of which are critical for healthy pregnancy outcomes.

5. Supports Mood and Emotional Health

Low magnesium levels are associated with higher rates of anxiety and depression, including postpartum depression (PPD).
Some evidence suggests that maintaining optimal magnesium levels during pregnancy may help stabilize mood and reduce the risk of PPD.

6. Promotes a Healthier Start for Babies

Adequate magnesium intake can:

• Reduce the risk of low APGAR scores (a measure of a newborn’s health right after birth)

• Lower the likelihood of admission to neonatal intensive care (NICU)

• Support healthy fetal growth and muscle tone

Best Sources of Magnesium for Pregnant People

Food Sources

Natural dietary intake is the safest way to meet your magnesium needs.

Including a variety of these foods daily supports overall nutrient balance—not just magnesium.

When Supplements Are Needed

If your diet doesn’t meet your magnesium requirements, your healthcare provider might recommend supplementation.

The best-known forms of magnesium include:

Magnesium Sulfate

Magnesium sulfate (MgSO₄) is widely used in hospitals for serious pregnancy complications.
The World Health Organization (WHO) recommends magnesium sulfate as a first-line treatment for preeclampsia and eclampsia.

It’s typically given through IV infusion and closely monitored for safety.

Outside hospital settings, magnesium sulfate can also appear as Epsom salt, commonly used in warm baths to soothe muscle aches and tension.
However, oral magnesium sulfate should not be taken without medical approval, as it can cause diarrhea or dehydration.

Magnesium Citrate

Magnesium citrate is one of the most easily absorbed forms of the mineral and is often used to relieve mild constipation during pregnancy.

A 2021 clinical study found that 360 mg of magnesium citrate per day reduced leg cramps and improved muscle relaxation in magnesium-deficient pregnant people.

It’s generally well-tolerated, though it may have a mild laxative effect.

Magnesium Oxide

Magnesium oxide contains a high percentage of elemental magnesium but is less bioavailable (not absorbed as easily).
It’s often used to treat migraines or headaches during pregnancy and can be safe up to 400 mg per day under medical guidance.

One potential side effect: it may delay breast-milk production, so postpartum monitoring is important.

Magnesium Bisglycinate

This gentle, highly absorbable form of magnesium binds to the amino acid glycine, making it easy on the stomach.

Clinical studies suggest 300 mg of magnesium bisglycinate can effectively reduce nighttime leg cramps in pregnancy without significant gastrointestinal discomfort.

This form is ideal for people who can’t tolerate other types of magnesium due to nausea or diarrhea.

Possible Side Effects and Precautions

When taken within the recommended dose, magnesium is generally safe during pregnancy.
However, overuse or sensitivity can lead to unpleasant side effects.

Common Side Effects:

• Diarrhea

• Stomach upset or nausea

• Flushing and sweating

• Headaches

• Dizziness or blurred vision

• Muscle weakness

If you experience severe reactions such as vomiting or persistent diarrhea, stop taking the supplement and contact your healthcare provider immediately.

Magnesium Interactions

Magnesium can affect the absorption of other nutrients and medications, including:

• Iron supplements – take these at least 2 hours apart.

• Zinc – excessive magnesium can reduce zinc absorption.

• Antibiotics – magnesium can interfere with tetracycline and quinolone antibiotics.

Because dietary supplements are minimally regulated by the FDA, it’s important to purchase only reputable brands tested for purity and potency.

When To Talk to Your Doctor

Consult your healthcare provider if you:

• Have persistent cramps or fatigue despite dietary improvements

• Experience symptoms of preeclampsia (swelling, headache, vision changes)

• Have chronic kidney disease or heart issues

• Take multiple supplements or prescription medications

Your provider may recommend a blood test to check magnesium levels and determine the safest dosage or supplement form for your specific needs.

Practical Tips for Getting Enough Magnesium Naturally

1. Include at least two magnesium-rich foods in every meal.

2. Choose whole grains over refined ones.

3. Snack on nuts, seeds, and legumes instead of processed foods.

4. Stay hydrated—magnesium helps balance electrolytes.

5. Combine magnesium foods with vitamin B6 and calcium for better absorption.

A Quick Review

Magnesium supports muscle, nerve, and heart health for both you and your baby.
While most people can get enough from food, supplements may help fill gaps—especially for preventing preeclampsia, leg cramps, and fatigue.

Always consult your healthcare provider before starting magnesium supplements during pregnancy.
Proper dosage, form, and timing are key to maximizing benefits while minimizing side effects.