Choosing the Best Calcium Supplement for Pregnancy

What's up with my strong cravings for all things dairy right now?? Well, I did some investigating and check this out:

The amount of calcium your intestines absorb during pregnancy doubles!   

Another fun fact…about 80% of the calcium present in the baby’s skeleton at the end of pregnancy crossed the placenta during the third trimester and is mostly derived from the calcium in mom’s diet during pregnancy. The calcium mom eats seems to be the main way our bodies adapt to meet those high calcium demands during pregnancy (1). Amazing! That definitely explains the cravings and my baby needs the calcium with only 6 weeks left to grow.

How Much Calcium Does A Pregnant Woman Need? 

A pregnant woman needs 1,000 mg calcium per day and pregnant teenagers need 1,300 mg calcium per day (4).

A prenatal supplement isn’t going to provide a lot of calcium, and if needed, additional calcium can be supplemented alongside the prenatal supplement, especially in the third trimester of pregnancy when calcium's needed most. Calcium can be obtained from foods naturally rich in calcium, calcium-fortified foods and beverages, supplements, or a combination of all. 

A comparison of calcium-containing foods per serving relative to milk is shown here:


 Serving size

Calcium content        (milligrams, mg)

Servings needed to equal 1 cup milk


1 cup

 300 mg



 ½ cup

 35 mg


 Bok choy

 ½ cup

 79 mg


 Cheddar cheese

 1.5 ounces

 303 mg


 Chinese mustard greens

 ½ cup

 212 mg


 Orange juice with calcium citrate-malate

 1 cup

 300 mg



 ½ cup

 61 mg



 ½ cup

 115 mg


 Tofu with calcium

 ½ cup

 258 mg



 1 cup

 300 mg


*References 2 and 3.

Choosing A Calcium Supplement 

First things first, please examine the nutrition label. You are looking for the amount of "elemental calcium,” not the milligrams or grams of calcium compound. For example, a 600 mg calcium tablet can actually contain only 150 mg of elemental calcium. Most high-quality manufacturers will specify on the label the milligram content of the compound and also the milligram content of "elemental calcium." If the label does not present this information, it would be best to avoid that product.

Maximize Absorption Of Your Calcium Supplement

1.  Look for the highly absorbable forms of calcium…calcium citrate and calcium citrate-malate. I like this blend with a handful of vitamins and minerals involved in bone growth.  

2. The percentage of calcium absorbed in your intestines decreases as the quantity of calcium consumed increases (5). This means, to maximize absorption, divide your calcium intake into more doses throughout the day.

3. The time you take your calcium is important because calcium taken with a meal is usually better absorbed than calcium taken without a meal (6). 

4. Take a dose of calcium at bedtime. Adding calcium at night seems to result in less removal of calcium from our bones during the night (7).

5. Calcium combined with Vitamin D increases calcium absorption, so vitamin D added to your calcium supplement is a good thing. Get all your vitamin D and pregnancy tips here. I use this easy liquid vitamin D. One tiny drop provides 2000IU, which is a daily maintenance dose. 

One Last Perk About Calcium

Much research shows calcium supplementation during pregnancy decreases the severity of complications brought on by preeclampsia and also decreases your risk of delivering a premature baby (8, 9), especially in teenagers.

If you would like to read more pregnancy blogs, Vitamin D, DHA, probiotics and decreasing exposure to toxins are so important during pregnancy I wrote about them in separate blogs. Here's more information: vitamin D during pregnancyprobiotics during pregnancyhealthy fats during pregnancy, and 10 ways to decrease toxic exposure during pregnancy

Bottom Line: Get your calcium from your diet whenever possible, and if you need additional calcium, look for a highly absorbable form and spread your dosage throughout the day.

In Health and Happiness,

Kelly Harrington, MS, RDN

Registered Dietitian Nutritionist for Healthy Goods



1.  Cross NA, Hillman LS, Allen SH, Krause GF, Vieira NE. Calcium homeostasis and bone metabolism during pregnancy, lactation, and postweaning: a longitudinal study. Am J Clin Nutr 1995;61:514–23.  

2.  Pennington JAT. Bowes and Church’s food values of portions commonly used. 15th ed. New York: Harper & Row, 1989.

3.  US Department of Agriculture. Composition of foods: vegetables and vegetable products. Washington, DC: US Government Printing Office, 1989. (Agriculture Handbook no. 8-11)

4.  Institute of Medicine. Dietary reference intakes for calcium, phosphorus, magnesium, vitamin D, and fluoride. Washington, DC:  National Academy Press, 1997.

5.  Wilkinson R. Absorption of calcium, phosphate and magnesium. In:  Nordin BEC, ed. Calcium, phosphate and magnesium metabolism.  New York: Churchill Livingstone, 1976:36-1 12.

6.  Heaney RP, Smith KT, Recker RR, Hinders SM. Meal effects on calcium absorption. Am I Clin Nutr 1989:49:372-6.

7.  Blumsohn A, Al-Dehaimi AW, Hemngton K, Shao P. Eyre DR.  Eastell R.  Effect of timing of calcium supplementation on the circadian rhythm of bone collagen degradation.  Bone Miner Res 1993;8(suppl):S 158(abstr).

8.  Imdad A, Bhutta ZA.  Effects of calcium supplementation during pregnancy on maternal, fetal and birth outcomes.  Paediatr Perinat Epidemiol.  2012 Jul;26 Suppl 1:138-52.

9.  Villar J et al.  World Health Organization randomized trial of calcium supplementation among low calcium intake pregnant women.  Am J Obstet Gynecol.  2006 Mar; 194(3):639-49.  



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