Can you take magnesium while pregnant? What OB-GYNs want you to know

In this article:

• Magnesium benefits for pregnancy
• Recommended dosage
• Which form is best?
• Risks and side effects
• The bottom line

In this article

• Magnesium benefits for pregnancy
• Recommended dosage
• Which form is best?
• Risks and side effects
• The bottom line

Magnesium does a lot of heavy lifting in the body. This essential mineral helps regulate the nervous system, cardiovascular system, muscles, bones, and blood sugar levels. When magnesium levels dip too low, the effects can be serious.

Most people get enough through food, but pregnancy changes the equation. Between morning sickness, food aversions, and increased nutritional demands, it can be harder to meet your daily needs through diet alone. The good news: Oral magnesium supplementation is considered safe during pregnancy and can be a simple, effective way to fill the gap. Here’s what experts say about doing it right.

The benefits of magnesium during pregnancy

Magnesium is necessary and beneficial during all phases of life, but plays an especially important role during pregnancy. “Magnesium supplements are considered safe in pregnancy and have a plethora of health benefits when used in the correct amounts,” says Peter Guirguis, MD, OB-GYN and director of labor and delivery at Northwell’s Staten Island University Hospital.

Dr. Guirguis points to several benefits, including improved sleep, relief of leg cramps, decreased headaches, and relief of constipation. “Magnesium supplementation is also helpful for skeletal development of the fetus and, in certain high-risk preterm situations, can protect the baby from neural damage,” he adds. 

One review article adds to that picture, linking adequate magnesium intake during pregnancy to:

• Muscle relaxation
• Electrolyte balance
• High blood pressure regulation
• Reduced risk of serious complications like gestational diabetes, preterm birth, low birth weight, and preeclampsia

How much magnesium do you need?

The recommended daily magnesium intake during pregnancy is 350-360 mg, and most people can meet that through diet alone. Good food sources of magnesium include:

• Leafy green vegetables
• Beans and legumes
• Nuts and seeds, including pumpkin seeds
• Whole grains
• Dark chocolate
• Bananas

That said, pregnancy can make it harder to eat a balanced diet. Morning sickness, food aversions, and increased calorie needs can all get in the way. That’s where a supplement can help. Prenatal vitamins often contain magnesium, but only 50-100 mg.

Magnesium deficiency doesn’t always cause obvious symptoms, particularly in the early stages. When signs of deficiency do appear, they can include:

• Loss of appetite
• Nausea or vomiting
• Extreme fatigue
• Weakness
• Numbness or muscle cramps
• Seizures or abnormal heart rhythm (more common as the deficiency becomes severe)

Which form is best for pregnancy?

If you’re not getting enough magnesium through diet, a supplement can help. “The recommended daily amount of magnesium supplements during pregnancy is approximately 350 mg per day,” says Diana Kolettis, MD, maternal fetal medicine specialist and associate program director of the Obstetrics & Gynecology Residency Program at Tufts Medical Center. More is not always better. High doses can increase unwanted side effects, and “patients with kidney disease or certain chronic medical conditions should speak with their healthcare provider before starting supplementation,” she advises. Generally, it is advised to speak with your health care provider before starting any supplements or over-the-counter medications during pregnancy.

As for which form to choose, “there is not one single ‘best’ form for everyone, but some forms are often better tolerated than others,” Dr. Kolettis says. She recommends choosing supplements from reputable manufacturers and discussing any new supplement with your prenatal care provider, particularly if you’re taking other medications.

Here’s what to know about the three main types.

Magnesium glycinate

Magnesium glycinate is the form most often recommended during pregnancy. Dr. Guirguis calls it his top pick: “It is highly bioavailable and gentler on the stomach than the other forms on the market.” Vanessa Archil, MD, OB-GYN, chairperson of the department of obstetrics and gynecology at Saint Anthony Hospital in Chicago, agrees, noting it is “highly absorbable and has less of a laxative effect when compared to magnesium citrate.”

Magnesium glycinate coupons 

Magnesium citrate

Magnesium citrate is the form of magnesium that’s most likely to cause loose stools. This is usually undesirable, but it may have some benefits for certain pregnant women. “Magnesium citrate may help patients who are also struggling with constipation,” Dr. Kolettis says. 

Magnesium citrate coupons

Magnesium oxide

Magnesium oxide is the most widely available form, but it absorbs less efficiently than the others and is “more likely to cause gastrointestinal side effects,” Dr. Kolettis notes. It’s not the first choice for most pregnant women.

Magnesium oxide coupons

Potential risks and side effects

“Risks of magnesium supplementation in pregnancy are extremely rare,” Dr. Guirguis says. However, too much magnesium can be problematic. In extremely high doses, such as 5,000 mg daily, magnesium toxicity is possible. “This would result in a dangerous drop in blood pressure, irregular heartbeat, muscle weakness, difficulty breathing, and confusion,” Dr. Guirguis says. “The highest risk factor for this to occur would be overuse of laxatives.” Rarely, cardiac arrest may occur.

Side effects

That said, there are some potential side effects of magnesium supplementation. Most of these are gastrointestinal in nature and may be more likely with supplements like magnesium citrate. Possible side effects include:

• Upset stomach
• Diarrhea
• Nausea
• Vomiting

It’s best to contact your healthcare provider if you experience any new or concerning symptoms while taking a supplement, such as magnesium. Side effects are more likely with high doses of magnesium.

Interactions

“Magnesium supplements can also interact with certain medications, including some antibiotics and thyroid medications, so timing and dosing may matter,” Dr. Kolettis explains. Magnesium may interact with certain medications, such as oral bisphosphonates, tetracyclines, and quinolone antibiotics. In addition, some medications, including diuretics and proton pump inhibitors, can affect magnesium status. It can also compete with calcium for absorption, so it should be spaced out with other supplements.

You should also be wary of taking magnesium supplements if you are taking laxatives that contain magnesium, as you might end up with very uncomfortable GI symptoms. 

The bottom line

Magnesium is one of the most important nutrients you can prioritize during pregnancy. It supports fetal development, helps regulate blood pressure, and may reduce the risk of serious complications like preeclampsia and preterm birth. Most pregnant women can meet their needs through a magnesium-rich diet, but a supplement can be a smart addition when diet falls short.

If you do supplement, stick to 350 mg per day and choose a form that’s well-tolerated, like magnesium glycinate. Before adding anything new to your routine, check with your healthcare provider, especially if you take other medications or have an underlying health condition. A quick conversation can help you supplement safely and get the most out of it.