Short answer: Pregnant women need 900 mg of calcium per day, and the Swedish Food Agency states that women need 250 mg of magnesium per day, including during pregnancy. Dairy products are the largest source of calcium in Sweden, while magnesium is found in leafy greens, legumes, whole grains, and almonds. The caveat applies to a strictly vegetarian diet, where calcium intake may be too low without fortified foods.
How much calcium do pregnant women need?
The Swedish Food Agency's report on good food choices during pregnancy (2016) states a recommended intake of 900 mg of calcium per day. This is 100 mg more than for non-pregnant women. The same recommendation applies to young women who become pregnant before their skeletons have finished growing.
The body also absorbs more calcium from food when demand increases, for example during pregnancy, or when intake is low. Milk and dairy products are the largest source of calcium in Sweden. The report also mentions fish eaten with bones, nuts, seeds, legumes, and green leafy vegetables. Those who eat a strictly vegetarian diet may not get enough calcium and should choose calcium-fortified foods or supplements.
How much magnesium do pregnant women need?
According to the same report, the recommended intake for women is 250 mg of magnesium per day, and this also applies during pregnancy. Large amounts of magnesium are found in green leafy vegetables, legumes, whole grain products, and almonds. Mineral-rich, hard water can also contribute to intake.
Magnesium from supplements should not exceed 250 mg per day, as larger amounts can cause diarrhea. The German Federal Institute for Risk Assessment (BfR) suggests the same limit for supplements for people from the age of four, calculated in addition to diet. There, the discomforts are described as temporary within one to two days, and the agency recommends that the daily amount be divided into at least two doses.
Views on the need differ slightly. A review article in Nutrition Reviews (2016) argues that the need for magnesium increases during pregnancy and that many pregnant women do not meet it. It is also pointed out there that magnesium in blood serum is a weak measure of status. The studies are few and the evidence is limited, and the article's summary reports no results from supplement studies. The authors recommend that pregnant women eat magnesium-rich food.
What foods provide what? Figures and food sources
| Calcium | Magnesium | |
|---|---|---|
| Recommended intake during pregnancy | 900 mg per day | 250 mg per day |
| Compared with non-pregnant women | 100 mg more | Same |
| Food sources | Fil, yogurt, quark, milk, cheese, fish with bones, nuts, seeds, legumes, leafy greens | Leafy greens, legumes, whole grains, almonds, hard water |
| Supplements | No upper limit stated in the report | Maximum 250 mg per day |
More minerals are covered in the articles about iodine before and during pregnancy and about vitamins and minerals before pregnancy.
Fewer cases of high blood pressure in calcium studies – in women with low intake
A Cochrane review, summarized by the Norwegian Institute of Public Health, compared calcium supplements with placebo or no supplement in pregnant women. The results for high doses came from 14 studies with 15,730 women. High dose meant more than 1 g per day, usually 1.5–2 g. Most women had a low calcium intake, under 900 mg per day.
With moderate certainty, fewer women had high blood pressure, approximately 35 percent fewer. The incidence of preeclampsia was about half as high. The proportion of preterm births was at most around 40 percent lower, but at worst unchanged. The effect was probably slightly greater in women at high risk and in women with low calcium intake.
The doses in the studies are far above the 900 mg recommended as total daily intake. The Swedish Food Agency still does not conclude that calcium supplements are good for health, because the studies did not report what the women ate before they started. Therefore, intake from food is the starting point.
Frequently asked questions
Do I need to take calcium or magnesium supplements? The Swedish Food Agency report generally does not recommend vitamin and mineral supplements for preventive purposes. The exception is a strictly vegetarian diet, where the report advocates calcium-fortified foods or supplements. If you are unsure about your intake, you can discuss it with the midwife.
Can magnesium cause stomach problems? Yes. Larger amounts of magnesium from supplements can cause diarrhea. Therefore, 250 mg per day is stated as the upper limit for supplements, and the BfR recommends that the daily amount be divided into at least two doses.
Does 900 mg of calcium also apply to very young pregnant women? Yes. The report states the same recommendation for young women who become pregnant before their skeletons have finished growing.
Read also
- Vitamins and minerals before pregnancy – what is needed?
- Choline during pregnancy – what does food contribute?
- Iodine before and during pregnancy – needs and food sources
General information, not medical advice. Consult healthcare professionals about your own situation.
Sources
- Swedish Food Agency: Good food choices during pregnancy, report 13/2016
- Norwegian Institute of Public Health: Review of Cochrane review on calcium supplements in pregnant women (2014)
- BfR: Maximum daily level for magnesium in food supplements (2017)
- PubMed: Magnesium in pregnancy, Nutrition Reviews 2016