Magnesium supplements may or may not be recommended during pregnancy, and it depends on a few things: the amount of magnesium in your prenatal vitamin, the amount of magnesium you’re obtaining through your diet, and the purpose of supplementation.

Magnesium is a mineral that comes in many forms: citrate, glycinate, sulfate, and malate, just to name a few. The difference between types boils down to absorption and the reason for use. Many forms of magnesium have advantages when it comes to sleep and digestion. Prenatal vitamins contain magnesium—often magnesium oxide—but the type can vary from prenatal to prenatal. What’s important to note is the dosage.

Prenatal vitamins often contain low doses of magnesium, which make them safe for consumption. The Recommended Dietary Allowance for magnesium during pregnancy ranges between 350-400 milligrams per day, depending on your age. For people who eat a wide variety of foods, meeting your needs for magnesium is pretty doable; but for those who may not have as broad of a palate, or who have developed pregnancy-related food aversions, additional supplementation may not be a bad idea.

Just be mindful of the dosage, as too much magnesium can have a laxative effect. In cases like this, it’s best to consult your healthcare provider to determine the dose and type that’s right for you.