Can You Take Magnesium While Pregnant?
You likely already know that it’s beneficial to take a prenatal vitamin. But you might also be wondering if you need to take any other supplements on top of that. Magnesium, a supplement that can help with leg cramps, sleep and constipation, is one that’s been talked about a lot lately. While many of the best prenatal vitamins already contain magnesium, you might be curious if you could benefit from even more extra magnesium. So can you take magnesium while pregnant? Healthcare providers say it’s both safe and beneficial—but there are a few important things to keep in mind. Read ahead to learn more.
Magnesium is an abundant mineral in the body, according to the National Institutes of Health (NIH). Magnesium is required for a range of reactions and functions in the body, including muscle and nerve function, blood sugar control and blood pressure. You can get magnesium from foods—leafy greens are a great source—as well as take it in supplement form.
Magnesium is important for health, whether you’re pregnant or not. “Magnesium plays a big role in muscle and nerve function,” says Jessica Cording, MS, RD, CDN, a dietitian, health coach and author of The Little Book of Game Changers: 50 Healthy Habits for Managing Stress & Anxiety. The mineral also influences your blood pressure, blood sugar and digestion, she says.
Magnesium during pregnancy is beneficial for baby too. “In fetal development, magnesium plays a role in building baby’s skeleton, bones and teeth,” Cording says.
Magnesium can also help with certain health issues that may come up during pregnancy. “If someone is getting muscle cramps, for example, we want to look at their magnesium levels,” Cording says.
It’s generally considered safe to take magnesium during pregnancy, says Jennifer Wu, MD, an ob-gyn at Northwell Lenox Hill Hospital in New York City. “We haven’t found that it causes birth defects,” she says. Cording agrees. “I’ve worked with many expectant moms who take magnesium,” she says.
Taking magnesium while pregnant isn’t only safe—it’s good for you. “Most women are usually a little deficient,” Wu says. While Wu points out that many prenatal vitamins contain magnesium, you might also benefit from a separate magnesium supplement. Be sure to check in with your healthcare provider first.
The right dosage depends on your individual needs, as well as how deficient you currently are. Most expectant moms need between 350 to 400 milligrams a day, according to the NIH. But how much magnesium during pregnancy you need depends on how much of the mineral you’re currently getting from food, as well as why you’re taking it, Cording says—again, this is why it’s important to talk to your healthcare provider first.
There are a few potential benefits you might get from taking a magnesium supplement, according to the experts:
- It could help to support good sleep during pregnancy.
- It may help with leg cramps.
- It could help with restless leg syndrome.
- It could help relieve constipation.
- It may relieve headaches.
- It could lower feelings of stress.
Doctors also use magnesium to treat preeclampsia (high blood pressure during pregnancy), although that treatment is typically different from taking a standard pill. “We give it through an IV and at a high dose,” Wu says.
Keep in mind that taking too much magnesium can cause diarrhea, stomach cramps and nausea, according to the NIH. “If someone has a little more than they need, they’ll end up with digestive issues,” Cording says.
Which type of magnesium supplement should you try?
Magnesium comes in different forms, and it’s important to ask your doctor which type is best for you while you’re pregnant.
These are the most common forms that your healthcare provider will likely suggest:
- Magnesium glycinate. This form is usually recommended for sleep and relaxation, Cording says. “It’s shown to be very highly absorbable and very effective at helping your body calm down for sleep,” she says. However, it’s “very gentle on the gastrointestinal system,” Cording adds.
- Magnesium citrate. This is usually used to treat constipation, since it tends to cause a bowel movement anywhere from a half hour to six hours after you take it, according to Medline Plus.
- Magnesium sulfate. This can also be used for short-term constipation relief.
- Magnesium oxide. Magnesium oxide, which is the most common type of magnesium found in supplements, can be used to treat a range of health issues, including as an antacid and for constipation, according to Medline Plus.
- Magnesium L-threonate. This type of magnesium supplement has been shown to improve cognition.
- Magnesium hydroxide. This is in a class of medications called saline laxatives and is used to treat occasional constipation, per Medline Plus.
If you want to test your magnesium levels, it’s not a bad idea to take a magnesium blood test—but keep in mind that blood levels only represent a small amount of overall magnesium in the body, and you might still be deficient. Make sure to speak with your provider, and pay attention to your symptoms as well. Cording says you may notice these symptoms if your magnesium levels are low:
- Constipation
- Muscle cramps
- Feeling very stressed out
- Headaches
It’s important to point out that having these symptoms doesn’t automatically mean you’re struggling with low magnesium. That’s why it’s important to talk to your healthcare provider before adding a magnesium supplement to your pregnancy routine.
You can get a lot of your magnesium from foods, and experts recommend you try to increase your levels by having magnesium-rich foods. “I always recommend food sources as a first step,” Cording says. These are some of your best options if you’re looking to eat magnesium-rich foods, per the NIH:
- Pumpkin seeds: 1 ounce, or 156 milligrams
- Chia seeds: 1 ounce, or 111 milligrams
- Almonds: 1 ounce, or 80 milligrams
- Boiled spinach: ½ cup, or 78 milligrams
- Cashews: 1 ounce, or 74 milligrams
Frequently Asked Questions
Is 500 mg of magnesium safe during pregnancy?
The highest recommended daily allowance (RDA) for magnesium during pregnancy is 400 milligrams, so 500 milligrams is a little high. “The supplement is usually 100 milligrams,” Wu says. Talk to your doctor. “Always discuss any herbs or supplements with your doctor before starting them,” Wu says.
What is the best magnesium supplement for pregnancy?
The best magnesium supplement during pregnancy is one that will meet your needs—and that’s where a conversation with your healthcare provider comes in. “Ask your doctor specific questions on which form is best for you, what dosage to take and when to take it,” Cording says.
Should you try magnesium for headaches in pregnancy?
Magnesium may help with headaches in pregnancy—Wu says that some of her patients take the supplement for chronic migraines. “Because magnesium is involved in muscle and nerve function, and both can play a role in headaches, it could definitely be helpful,” Cording adds.
Again, if you’re concerned about your magnesium levels or have symptoms of low magnesium during pregnancy, talk to your healthcare provider about taking a magnesium supplement during pregnancy. They should be able to guide you on next steps.
Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.
Plus, more from The Bump:
Jessica Cording, MS, RD, CDN, INHC, is a dietitian, health coach and author of The Little Book of Game Changers: 50 Healthy Habits for Managing Stress & Anxiety.
Jennifer Wu, MD, is an ob-gyn at Northwell Lenox Hill Hospital in New York City. She earned her medical degree from the University of South Carolina at Charleston.
National Institutes of Health, Magnesium, June 2022
National Library of Medicine, Medline Plus, Magnesium Citrate, April 2019
National Library of Medicine, Medline Plus, Magnesium Hydroxide, April 2019
National Library of Medicine, Medline Plus, Magnesium Oxide, June 2024
Nutrients, A Magtein®, Magnesium L-Threonate, -Based Formula Improves Brain Cognitive Functions in Healthy Chinese Adults, December 2022
Nutrients, Magnesium: Are We Consuming Enough?, December 2018
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