Magnesium is an important nutrient that is responsible for over 300 processes in the body. Deficiency can be common during pregnancy and can result in some undesirable side effects.
We will review magnesium supplements, whether or not they are safe during pregnancy, and any benefits that can be provided by magnesium supplementation.
We will also review good food sources of magnesium. And finally, we will explore whether or not magnesium could be harmful during pregnancy.
Should I Take a Magnesium Supplement During Pregnancy?
Magnesium requirements do increase during pregnancy and when breastfeeding.
Luckily, there are a lot of foods that contain magnesium, which means you may not have to take a supplement at all. I’ve put together a list of magnesium-rich foods for pregnancy later in this article.
Prenatal vitamins usually contain some magnesium, but not enough to meet your daily 100% (which will be outlined a little later in the article).
One interesting fact published in the Journal of Pregnancy and Child Health found that one of the main reasons that magnesium requirements are increased during pregnancy is because over 50% of women are already magnesium deficient prior to becoming pregnant (Source: Research Gate)
Additionally, those with absorption disorders like Crohn’s disease, inflammatory diseases like Type II diabetes, and people with alcohol dependence are likely already magnesium deficient.
This is because their bodies do not digest and absorb as well as healthy people, so if you already have one of these conditions and become pregnant, the risk for magnesium deficiency might be even greater (Source: NIH).
Therefore, if you think you might be deficient in magnesium (for instance, if you are experiencing muscle cramps or increased heart rate), adding in some magnesium-rich foods would be a good way to start to meet your daily needs.
If you do choose to take a magnesium supplement during pregnancy, you’ll find that there are a lot of different types of magnesium supplements on the market, so let’s take a quick look at what is out there, and why it might be used.
We will review Magnesium Citrate a little later on in this article.
Magnesium Oxide
It’s important to know that your body only absorbs a certain percentage of magnesium, so even if you think you might be getting too much, a quick check with your medical professional would be a good idea.
This is a form of magnesium bound to an oxygen molecule that is used for indigestion and constipation. It’s inexpensive but may not be absorbed as quickly or effectively by the body (Source: NIH).
Magnesium Chloride
This is a form of magnesium that could be given during hospitalization, as an intravenous injection. It can also be taken orally.
It is commonly used as a supplement to help prevent or treat magnesium deficiency. It is also used as a sleep aid, which we will discuss more later on in the article (Source: NIH)
Magnesium Sulfate
Commonly used as a treatment and prevention for preeclampsia, magnesium sulfate may also help with cognition, as it has the ability to help dilate the circulatory system (Source: NIH)
Magnesium Aspartate
This is an over the counter supplement commonly taken to help treat magnesium deficiency.
It can be taken as a pill or powder, and could have some undesirable side effects including diarrhea, cramps, and gas.
It looks to be safe to take magnesium aspartate during pregnancy, with no known side effects, but check with your medical professional to determine if you need to take a supplement. (Source: rxlist)
Magnesium Lactate
Magnesium lactate is a supplement that combines elemental magnesium with lactic acid.
This form appears to be more bioavailable, meaning that your body can more effectively use the magnesium from the supplement.
There appears to be only one company that sells this form of magnesium, so a double-check with your doctor before consumption during pregnancy is probably best (Source: Drugs).
Is Magnesium Citrate Safe While Pregnant?
Magnesium Citrate is the form of magnesium found in the body. It is also the form of magnesium found in food. Chemically, it is a molecule of magnesium bound to citric acid (Vitamin C).
As I’ve already mentioned, there is an increased need for magnesium during pregnancy, since it seems that women tend to excrete more in the urine.
Plus magnesium citrate was the form of supplement used in one of the research studies published in the Journal of Pregnancy (Source: Journal of Pregnancy).
Magnesium Citrate does appear to be safe during pregnancy, but check with your medical professional if you have any questions.
Magnesium Dosage: How Much Do Pregnant Women Need?
For pregnant and breastfeeding women, magnesium needs increase based on age. Here is a quick breakdown:
| Age | During Pregnancy | When Breastfeeding |
|---|---|---|
| 14 – 18 | 400 mg | 360 mg |
| 19 – 30 | 350 mg | 310 mg |
| 31 – 50 | 360 mg | 320 mg |
As previously stated, needs likely increase because of the prevalence of deficiency among women who are not yet pregnant.
When your baby is developing, magnesium is required for the healthy growth and development of your baby.
Additionally, during pregnancy, magnesium appears to be excreted 20% more than when not pregnant, mainly due to increased heart rate and increased urine production that happens during pregnancy.
What Are The Benefits of Magnesium During Pregnancy?
Magnesium can help to regulate heart rate, and is one of the main treatment interventions in treating preeclampsia.
Magnesium has several other important benefits for women during pregnancy. These are:
Magnesium can Help Prevent Preterm Birth
Preterm birth is the leading cause of infant death. A common treatment to help prevent early uterine contractions is magnesium, given orally or as an infusion.
Research does show that women who have a higher incidence of preterm birth tend to have lower serum magnesium levels.
However, other conflicting research shows no difference in magnesium blood levels in women who delivered early compared to those who delivered on time (Source: Academic)
Magnesium May Decrease the Risk of Gestational Diabetes
Gestational diabetes can affect up to 15% of pregnant women, and can increase the risk of delivery complications, and health complications after birth for both you and your baby.
Obesity appears to increase the risk for development of Gestational Diabetes, which can also lead to an increased risk for developing Type II diabetes.
Research shows that magnesium intake may help to decrease the risk for developing Type II diabetes.
Magnesium supplementation appears to help improve insulin sensitivity (the body’s ability to use insulin to reduce blood sugar), and can help to improve fasting blood glucose levels over time.
Of course, check with your medical professional to see if adding magnesium is right for you, but know that it might help to prevent or treat Gestational Diabetes (Source: Nutrition Reviews).
Magnesium May Help with Cramp or Leg Cramps When Pregnant
Leg cramps are common during pregnancy, with anywhere from 5-50% of pregnant women experiencing cramping.
Frequency and severity appear to be worse during the later stages of pregnancy. Thankfully, magnesium supplementation may help.
A study (small, with 73 participants) found that magnesium supplementation during pregnancy helped to reduce the severity and frequency of leg cramps (Science Direct).
Because magnesium is a water-soluble nutrient, excess amounts are excreted in urine, so magnesium toxicity is likely very rare.
We were not able to determine the form or amount provided, which may influence the results.
In contrast, a study published in early 2020 found that magnesium citrate supplementation did not reduce severity or frequency of leg cramps during pregnancy in 130 pregnant women(Plos One).
Additionally, a few of the participants experienced gastrointestinal side effects like diarrhea and nausea.
Magnesium may help for leg cramps during pregnancy, but it will likely depend on the form and amount that is provided.
It’s best to check with your medical professional before adding anything to your pregnancy nutrition regimen.
Magnesium For Pregnancy-related Migraine Headaches
Migraines may increase during pregnancy for women who already experience them, or may develop in women who have never had a migraine.
Some research shows that migraines and magnesium levels may have a direct relationship, and other research shows that migraine may be a precursory marker for increased risk for other health issues including preeclampsia, cardiovascular disease, and gestational hypertension.
More research is likely needed in this area, but if you suffer from migraines, especially during pregnancy, incorporating a magnesium supplement might be a good idea (Source: Academic).
Magnesium Can Promote Your Baby’s Healthy Growth and Development During Pregnancy
This topic seems pretty general, but refers specifically to helping prevent intrauterine growth restriction and babies born small for their gestational age.
Preterm delivery, small growth rate, genetic abnormalities, low weight, and increased morbidity are all associated with babies born small for gestational age or with intrauterine growth restriction.
It appears that magnesium levels in babies born with these traits tend to have lower serum magnesium levels, which would suggest that maternal magnesium supplementation may help to prevent these abnormalities. (Source: Nutrition Reviews)
Magnesium to Help Promote Sleep During Pregnancy
During pregnancy there is nothing that you probably want more than a restful night’s sleep! Magnesium might be able to help with that.
Magnesium can help to regulate melatonin and quiet the nervous system, helping you to sleep well and wake up feeling refreshed (Source: Pubmed).
In fact, a study published in 2015 did show a relationship between magnesium deficiency and disrupted sleep patterns, meaning that a supplement might be a good idea (Source: Science Direct).
Is Too Much Magnesium Dangerous During Pregnancy? Side Effects
Magnesium is a water soluble nutrient, meaning that any extra in the body will be excreted through urine or sweat.
If you eat a lot of magnesium from food sources, the risks of toxicity are likely low. However, consuming too many magnesium supplements or medications could pose a health risk.
The body can only get rid of so much, and because supplements are not regulated, it’s difficult to determine how much you could be ingesting or absorbing.
Side effects of too much magnesium include diarrhea, nausea, abdominal cramps, low blood pressure, muscle weakness, difficulty breathing, irregular heartbeat, and could even lead to death in extreme cases.
If kidney function is impaired, the risk for magnesium toxicity does increase, as the kidneys are not as efficient in filtering everything out of the blood.
It does appear that too much Magnesium sulfate taken during pregnancy is one of the medications that could interfere with your baby’s ability to breathe properly.
However, the instance where this would likely occur is rare, and usually only if you require large amounts of intravenous magnesium (and not from food).
In this case, you’d be closely monitored to make sure you and your baby are as healthy as can be with risks minimized as much as possible. (Source: Nursing for Women’s Health)
Magnesium-Rich Foods for Pregnancy
The good news is that you can increase your magnesium intake during pregnancy by eating magnesium-rich foods.
Here are some good food sources that contain more than 60 milligrams of magnesium, that are safe to consume during pregnancy (Source: NIH):
1. Roasted Pumpkin Seeds
Magnesium Content: 156 milligrams per 1 ounce serving
A sprinkle of pumpkin seeds on yogurt is a delicious way to start the day. The fiber in pumpkin seeds can also help with any constipation, making it a super nutritious addition to your pregnancy diet.
We have a dedicated article to pumpkin during pregnancy too.
2. Chia Seeds
Magnesium Content: 111 milligrams per 1 ounce serving
Not only are chia seeds a great source of magnesium, but are also a nutrition powerhouse!
11 grams of fiber and 4 grams of protein means that adding these to a smoothie can really help to boost your overall nutrition during pregnancy. You can read more here about chia seeds during pregnancy.
3. Baked Potato (with skin)
Magnesium Content: 98 milligrams per 8 ounces
Not only are potatoes a great source of magnesium, they also offer potassium, fiber, and healthy carbohydrates. Their soft, mild flavor can also help to soothe your stomach if nausea strikes. They’re on our top foods to fight pregnancy-related nausea.
4. Roasted Almonds
Magnesium content: 80 milligrams per 1 ounce serving
Almonds are great on their own or as a snack with some dried fruit. They can also be eaten in almond butter form on whole wheat toast for a filling, magnesium rich snack.
5. Spinach
Magnesium Content: 78 milligrams per ½ cup cooked
Spinach is one of the most nutritious green vegetables, and is a great addition to your pregnancy-friendly diet.
Spinach has a mild flavor, so adding it to smoothies is an easy way to sneak in a little extra magnesium.
You can also eat it sauteed with garlic and olive oil, served with a lean protein for a delicious, nutritious meal.
If eating it raw, always wash the spinach – there’s a guide to salad safety in pregnancy right here.
6. Roasted Cashews
Magnesium Content: 74 milligrams per 1 ounce serving
Cashews are one of the higher-fat nuts, so be mindful of serving size; they are also very delicious and easy to snack on!
Their magnesium content, along with protein, fat, and fiber content, do make them a nutrient-dense snack that is easy to eat on the go, while running errands or at work.
7. Roasted Peanuts
Magnesium Content: 63 milligrams per ¼ cup serving.
Peanuts are a legume (as opposed to tree nuts), and are in the same family as soybeans and other beans.
They can be eaten as a snack, spread as peanut butter on toast, or even incorporated into a morning bowl of oats or porridge. Read more about the benefits of peanuts during pregnancy.
8. Soy Milk
Magnesium Content: 61 milligrams per 1 cup serving
If you are lactose intolerant, soy milk is a great non-dairy alternative to add to your bowl of morning cereal (or oatmeal).
Be mindful of sweetened beverages if gestational diabetes is a concern, as some sweetened milks can be high in added sugar. For more on this, check our pregnancy guide to soy milk.
The magnesium content, along with other nutrients like potassium and protein, make it a great addition to your pregnancy (and breastfeeding) diet.
9. Black Beans
Magnesium Content: 60 milligrams per ½ cup cooked
Black beans are commonly eaten with rice, but can also be made into a spread, added to soup or stew, or even sauteed with onions and corn for a delicious, filling, magnesium-rich side dish.
We love a black bean salad dressed with cilantro, lime, and a little olive oil!
Overall, a good rule of thumb is that if a food contains fiber, it might contain some magnesium. Foods that are processed tend to be lower in magnesium because they have had a lot of their fiber removed.
This is another great reason to consume whole grains rather than their processed counterparts (think brown rice instead of white or whole grain bread instead of white bread).
Magnesium can also be found in drinking water, but in smaller amounts.
Therefore, a combination of magnesium rich foods and a high quality prenatal vitamin should help you to meet your magnesium needs.
We hope this helps you understand the benefits of adding magnesium to your pregnancy diet, and the benefits it can give you and your baby, too.
This article has been reviewed and approved for publication in line with our editorial policy.