Magnesium and Pregnancy: How to Get Enough

Magnesium and Pregnancy: How to Get Enough

Magnesium is an essential mineral that is needed by the body to regulate many different systems in both adults and children. Pregnant women need to increase their intake of magnesium not only because they are growing little babies in their bodies that also need this valuable mineral, but because its absence can cause some unique complications during pregnancy.

One of the primary jobs of magnesium is to relax your muscles. Some studies suggest that insufficient magnesium intake may lead to premature uterine contractions. This valuable mineral is also needed by the baby to develop healthy and strong bones and teeth. Some studies further claim that insufficient magnesium may cause the mothers to feel even more fatigued and have a lack of muscle strength.

Due to these reasons, it’s crucial that pregnant women get enough magnesium during pregnancy. If they don’t, they may put themselves at an increased risk for certain pregnancy complications. Thankfully, the amount of magnesium pregnant women need isn’t hard to reach with supplements and a healthy diet.

How Much Magnesium Do Pregnant Women Need?

The amount of magnesium needed during pregnancy will depend on the age of the pregnant mother, as well as whether they are breastfeeding or not. The rule of thumb is that pregnant women who are 19 years of age and older should aim to get around 350 mg of magnesium in their diet every day, while pregnant women who are 18 years of age and under should aim to get over 400 mg of magnesium.

Magnesium While Breastfeeding

Breastfeeding mothers should also consume more magnesium, as they’ll pass off some of their supply to their babies. Most experts recommend aiming for a daily intake of about 400 mg while breastfeeding. They also recommend taking magnesium supplements or consuming more magnesium through a healthy, balanced diet throughout the entire pregnancy and until the end of breastfeeding.

Signs of Magnesium Deficiency

Most people will get enough magnesium from their diet; however, pregnant women who can’t stomach any food may have difficulties getting the daily requirements. Some health conditions, like chronic alcoholism, Crohn’s disease and intestinal surgery, can also affect a person’s ability to absorb magnesium.

When this happens, it’s not unusual for the affected individual to notice signs of magnesium deficiency. They include:

  • Appetite loss
  • Fatigue
  • Muscle cramps
  • Nausea
  • Numbness and tingling
  • Seizures
  • Vomiting

If you notice any of the signs of magnesium deficiency above, talk to a healthcare professional immediately. These signs can also be an indication that there is something else that’s wrong.

Your doctor will look at your blood magnesium levels to see whether you have a magnesium deficiency. Normal magnesium levels are generally between 0.6 to 1.1 mmol/L. Anything under 0.6 mmol/L is defined as deficient.

If you are experiencing the symptoms above and have a diagnosed magnesium deficiency, the quickest solution is to start taking magnesium supplements while simultaneously working on adopting a healthier diet.

Foods Rich in Magnesium

a photo of foods that are rich in magnesium

Most healthcare professionals recommend pregnant women to get all of the magnesium that they need from a healthy, balanced diet. Fortunately, this valuable mineral is found naturally in many food items, like:

  • Dark chocolate, which contains around 50 mg of magnesium per every 1-ounce serving
  • Dry, roasted almonds, which contain about 80 mg of magnesium per every 1-ounce serving
  • Kidney beans, which contain 35 mg of magnesium per every 1/2-cup serving
  • Plain, low-fat yogurt, which contains 42 mg of magnesium per every 8-ounce serving
  • Pumpkin seeds, which contain about 168 mg of magnesium per every 1-ounce serving
  • Salmon, which contain 26 mg of magnesium per every 3-ounce serving
  • Soymilk, which contains 61 mg of magnesium per every 1-cup serving
  • Spinach, which contains about 78 mg of magnesium per every 1/2-cup serving
  • Whole wheat bread, which contains 46 mg of magnesium per every 2 slices
  • White rice, which contains 10 mg of magnesium per every 1/2-cup serving

A lot of other food items contain a healthy amount of magnesium. In general, you’ll find lots of magnesium in greens, nuts, seeds, whole grains and beans. It’s easy to incorporate these foods into your diet by eating more salads. You can also try eating more rice dishes into your diet.

Magnesium Supplements

Another way to up your magnesium intake during pregnancy is to take supplements. In general, this isn’t necessary for most pregnant women who are eating healthy, balanced diets. However, some women may want to add magnesium supplements to their diet if they have difficulties stomaching food.

With that said, you should look for supplements that contain less than 100 mg of magnesium oxide if you’re also taking iron supplements, as any amount larger than this may reduce your body’s ability to absorb iron. There are several different types of magnesium supplements that you can take. The different options include:

  • Magnesium chloride, which is often found in capsules or tablets and can be used to treat heartburn and constipation
  • Magnesium citrate, which is found naturally in citrus fruits and is considered the most bioavailable form of magnesium available
  • Magnesium malate, which is often found in fruit and wine and may have less of a laxative effect on your body
  • Magnesium sulfate, which is also known as Epsom salt and is often dissolved in bathwater to help ease sore muscles
  • Magnesium taurate, which can also help improve blood sugar levels thanks to the taurine in it

Magnesium is also found in many prenatal supplements in small quantities. Check the nutrition label to see how much magnesium is present. Most prenatal supplements will contain several hundred milligrams of this mineral. You should look at the type of magnesium that is used, as different types may have different effects.

Studies have shown that it’s better to take effervescent magnesium tablets rather than multimineral tablets if you plan on adding magnesium supplements to your day-to-day life. Effervescent magnesium tablets do a better job at preventing intrauterine growth retardation, preterm labor, pregnancy-induced hypertension, preeclampsia, leg cramps and gestational diabetes mellitus.

Transdermal Magnesium Absorption

green jar of salts and containers with oils

There are a lot of misconceptions behind whether it’s better to take magnesium supplements or to apply magnesium lotions and oils. There’s a lot of confusion surrounding whether magnesium is better absorbed through the skin, otherwise referred to as transdermal absorption.

While some studies have found that serum magnesium levels have increased with transdermal absorption, the difference was rather negligible and only affected a subgroup of participants. There aren’t many studies that have found a noticeable difference.

Due to this reason, it’s best to opt for magnesium supplements rather than magnesium oils and lotions. However, if you have the funds for it, there’s no harm in trying both. You can always take more baths with Epsom salts that contain magnesium, as the magnesium may soak through your skin.

Complications of Low Magnesium Intake During Pregnancy

pregnant woman in pain and calling for help

As mentioned previously, magnesium is a valuable mineral and not enough of it can contribute to pregnancy complications. However, these complications usually arise when there are problems with the mother’s diet. Pregnant women who are eating a healthy, balanced diet seldom need to consume more magnesium, although it rarely hurts.

Some of the most common health complications that are associated with poor magnesium intake during pregnancy include preterm labor and birth, preeclampsia, gestational diabetes, poor fetal growth, leg cramps and migraines.

Preterm Labor and Birth

The leading cause of perinatal mortality is associated with preterm birth. In the US, the incidence of preterm birth is fairly low, so there haven’t been too many studies on the use of magnesium to prevent this from happening.

With that said, some studies that looked at other cultures have found that magnesium may inhibit preterm uterine contractions by helping your muscles relax. After all, magnesium blocks calcium, which causes muscles to contract.


Preeclampsia is one of the most common pregnancy complications. It is characterized by high blood pressure and most pregnant women will also experience some type of damage to their organ systems, especially their liver and kidneys. This pregnancy complication usually begins at about 20 weeks of pregnancy.

Studies have found that magnesium supplements may help prevent preeclampsia. In fact, magnesium sulfate is often the most recommended form of magnesium used to treat this complication. By taking magnesium supplements early on, you might be able to avoid this complication altogether.

Magnesium supplements are believed to reduce blood pressure in pregnant women to prevent hypertensive disorders associated with pregnancy. Although magnesium is great for lowering blood pressure in pregnant women, it’s important to note that there are also other risk factors for preeclampsia, like obesity or insulin resistance.

Gestational Diabetes

Approximately 1% to 14% of pregnant women will struggle with gestational diabetes mellitus (GDM). GDM is associated with an increased risk of preeclampsia and a need for cesarean section delivery. It has also been linked with shoulder dystocia or birth injury and newborn adiposity.

Those with GDM are thought to have insufficient magnesium because this mineral plays many important roles in the insulin-signaling pathway. If there isn’t enough magnesium in your diet, you’re more likely to develop GDM, which can in turn lead to the development of type II diabetes. That said, GDM will usually disappear by itself after pregnancy unless it develops into type II.

Poor Fetal Growth

Some studies suggest that low magnesium intake may be associated with intrauterine growth restriction (IUGR) and small for gestational age (SGA) diagnoses. Both of these terms essentially mean that the baby is smaller than expected. Magnesium, along with other vitamins and minerals, can increase overall birth weight and reduce the risk for preterm labor.

Leg Cramps

Approximately 30% of pregnant women get leg cramps during their pregnancy. If this resonates with you, then you should consider adding more magnesium into your diet. Magnesium helps muscles relax, and some studies have shown that taking a highly absorbable form of magnesium, like magnesium glycinate chelate, can help reduce the frequency of leg cramps.


Migraines are often attributed to hormonal changes, and many pregnant women will experience their first migraine when they’re pregnant. Those with a history of migraines will usually experience an increase in the frequency and intensity of their migraines within the first trimester.

Some studies have also found that adding magnesium supplements to a pregnant woman’s diet can lower their likelihood of migraines for a smoother pregnancy. There have also been studies that suggested that magnesium supplements can help non-pregnant women reduce the number of migraine attacks that they experience as well; however, there are a lot of critiques for those studies, and criticisms usually revolve around how the results for those conclusions are rather weak. Still, unless you’re taking too much magnesium, it can’t hurt, so it’s worth a shot if you’re suffering from migraines while pregnant.

Side Effects of Taking Too Much Magnesium

Although magnesium is a valuable mineral, taking too much of it is known to come with one single side effect — a need to go to the washroom. This is because excess magnesium will go through the kidneys and be excreted through urine and stool. The excess magnesium can have a slightly laxative effect; however, many pregnant women struggle with constipation and may find this side effect to be a welcome bonus at times.

The only exception is a massive overdose at a level that you’re unlikely to unintentionally achieve through diet or supplementation, which can cause more serious side effects including an irregular heartbeat, vomiting, and the possiblity of organ failure. However, this requires as much as 5,000 mg of magnesium to occur, making it very uncommon.

Be Mindful of Your Diet

Make sure that you get enough magnesium by being mindful of your diet. If you’re eating a healthy, balanced diet, you likely won’t need to include any magnesium supplements at all. Still, if you’re not sure, there’s no harm in speaking with a healthcare professional about your situation.

A healthcare professional can conduct tests to determine whether you have enough magnesium in your body and whether you need to make any dietary changes to get more magnesium during pregnancy.