Is it Safe to Take Magnesium When Pregnant?

While research shows that magnesium supplements can be beneficial during pregnancy, taking them without your doctor’s approval is not a good idea.
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Magnesium is a mineral that may or may not be on your radar. However, your body needs additional magnesium during pregnancy, so it's important to make sure you're getting enough.



While research shows that magnesium supplements can be beneficial during pregnancy, taking them without your doctor’s approval is not a good idea. When consumed in excess, this mineral may cause adverse effects.

Read more: Difference Between Magnesium and Manganese

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Importance of Magnesium During Pregnancy

According to the National Institutes of Health (NIH), magnesium is an essential mineral required for more than 300 different biochemical reactions. Your muscles need this nutrient to contract, your nerves need it to transmit signals and your heart needs it to beat steadily.


Magnesium keeps your immune system healthy, regulates blood sugar levels, keeps your bones strong and assists in the production of proteins and energy. This mineral may also play a role in the prevention and management of health conditions like high blood pressure, heart disease and diabetes, although the NIH notes that research in these areas is still ongoing.

Furthermore, magnesium is vital for a healthy pregnancy. A July 2016 study published in the journal Nutrition Reviews notes that a deficiency of magnesium during pregnancy is associated with conditions like gestational diabetes, preeclampsia, premature labor and other complications.


The NIH recommends the following magnesium intake for pregnant women per day:

  • Women between the ages of 14 and 18: 400 milligrams of magnesium
  • Women between the ages of 19 and 30: 350 milligrams of magnesium
  • Women between the ages of 31 and 50: 360 milligrams of magnesium

These values are around 40 milligrams higher than the daily recommended values for women who are not pregnant. Nursing mothers don't require additional magnesium — in their case, the recommended values are the same as those for women who are not pregnant.


Sources of Magnesium

Magnesium occurs naturally in a wide range of foods, so deficiencies are rare. Plus, it is added to many fortified products.

The NIH lists some of the natural sources of magnesium, which include spinach, bananas, potatoes, avocados, dried apricots, peanuts, cashew nuts, almonds, beans, peas, seeds, soy products like tofu and soy milk, brown rice, millet, milk and yogurt. Foods that have dietary fiber tend to be good sources of magnesium.



Of these, almonds are perhaps one of the best sources of this mineral. One ounce contains 80 milligrams of magnesium, providing over 20 percent of the daily recommended intake, according to the NIH.

You may be surprised to find out that magnesium happens to be a key ingredient in certain medications like laxatives, antacids and heartburn remedies.

A tablet of Extra-Strength Rolaids, for example, contains 55 milligrams of magnesium, states the NIH. Tums, on the other hand, don't contain any magnesium at all. Even some types of tap water and bottled water can contain up to 120 milligrams of magnesium per liter, depending on the source and brand.


Despite the wide availability of naturally occurring magnesium, the NIH notes that dietary surveys of Americans consistently found that magnesium intake was below the recommended amounts. The last survey was conducted between 2005 and 2006, and there is no current data available.

Magnesium is available in supplement form for those who are deficient. There are several types of magnesium supplements, including oxide, citrate, sulfate and chloride formulations.


Read more: Magnesium Malate vs. Magnesium Citrate

Factors That Affect Magnesium Absorption

Only 30 to 40 percent of the magnesium you consume through your diet is absorbed by the body, as the NIH notes. The human body contains roughly 25 grams of magnesium, of which 50 to 60 percent is stored in the bones. The rest can be found in your soft tissues. Less than 1 percent of the total amount of magnesium you consume circulates in your bloodstream.


Approximately 120 grams of magnesium is excreted in the urine every day. Your kidneys play an important role in regulating the balance of magnesium in your body.


Alcohol abuse, gastrointestinal disease, type II diabetes and age-related issues can all affect how much magnesium your body is able to absorb. These factors may increase your chances of developing a magnesium deficiency.

How well your body can absorb this mineral in supplement form depends on the product. Supplements that dissolve in water tend to be absorbed better by the gut, points out the NIH.

Read more: Should You Take Calcium and Magnesium Together?

Supplementing Magnesium During Pregnancy

A February 2017 study published in the Journal of Pregnancy and Child Health notes that pregnant women tend to have symptoms of magnesium deficiency, like calf muscle cramps and muscle spasms, dysmenorrhea, gastrointestinal spasms, uterine contractions and premature labor. Researchers concluded that magnesium supplementation is essential for expecting mothers who exhibit these symptoms.

An August 2017 clinical trial published in the journal_ Advanced Biomedical Research_ found that giving pregnant women a 200-milligram magnesium supplement in addition to a multi-mineral tablet that contained 100 grams of magnesium produced better outcomes than giving them just a multi-mineral tablet.

Women who were given the additional magnesium supplement had fewer pregnancy-related complications. Researchers state that the correct dose of magnesium supplements can not only treat some pregnancy disorders, but it may also help prevent preeclampsia, preterm delivery, low birth weight and other problems that may occur. These findings justify the need for additional magnesium during pregnancy.

Are Magnesium Supplements Safe?

It's important that you consult your health care provider before taking magnesium supplements or any other pregnancy supplements for that matter. Since your kidneys flush out excess magnesium through your urine, the amounts you would normally obtain from your diet don't pose a risk to your health. However, the same doesn't apply to the magnesium obtained from supplements.


Read more: Are Supplements Safe? Here's What You Really Need to Know

The NIH warns that high doses of this mineral obtained from medications or dietary supplements often result in nausea, diarrhea and abdominal cramping. Therefore, it is recommended that all adult women, regardless of whether they are pregnant or lactating, limit their magnesium intake from supplements to a maximum of 350 milligrams per day.

Since these side effects apply to anyone who consumes excess magnesium via supplements and are not specific to pregnant women, it's even more critical that you consult your healthcare provider before popping pills. There could be other risks to you and your baby as well, and your doctor can ferret them out.

Extremely high doses of magnesium, in the vicinity of 5,000 milligrams per day, have been shown to cause magnesium toxicity, which can be fatal.




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