You’re pregnant and your close ones keep pestering you to drink milk because you need to load on calcium. The thing is you’re not really a dairy person. So, is it such a big deal if you’re not getting enough of the mineral?

Well, yes, it definitely is! Did you know that calcium plays a key role in the function of almost every cell in your body and that of the tiny life growing inside of you? This article briefly reviews the roles of calcium during pregnancy and will give you tips on how to meet your needs.

Why is calcium important in pregnancy?

It’s common knowledge that calcium is crucial for proper foetal bone and teeth development. But were you aware that you and your baby need calcium to maintain a normal heart beat? Or that adequate hormone secretion, muscle contraction, nerve transmission and blood clotting depend on your calcium intake?

So how much calcium do you need?

The RNI for calcium during pregnancy is 700mg per day – the same amount a woman needs prior to pregnancy. The reason why your needs remain unchanged is that, in an attempt to protect your skeleton, your body will adapt by:

  • Doubling your levels of 1,25-dihydroxyvitamin D which, in turn, doubles the rate at which calcium is absorbed from your intestines. Researchers explain that this increase in bone density occurs from as early as 12 weeks into your pregnancy as your body starts storing calcium to meet your baby’s needs during the 3rd trimester.
  • Decreasing the amount of renal calcium loss.
  • Boosting the absorption of calcium from your skeleton.

What if you’re a pregnant teenager?

Then you’ll need to get about 800mg of calcium daily.

Why the difference? Well, after testing the forearm of adolescent mothers, researchers found that their bone density decreased by as much as 10% during pregnancy and lactation. This was not observed in women above 18.

The scientists speculate that, since a teen mother is still building her total bone mass, the growing baby may be competing with her for calcium to develop his own skeleton. An inadequate intake could thus prevent the young mother from achieving her optimal bone density – this may render her more vulnerable to osteoporosis later on.

So if you’re under 18, increase your dietary intake of calcium to compensate for the decline in bone density.

More information on nutritional needs in adolescent pregnancy

Dietary sources of calcium

You’re probably aware that the best sources of calcium are milk and dairy products such as yogurt and cheese. But what if you’re vegan, lactose intolerant or an adherent of the paleo diet?

Good news: you can get sufficient calcium from green leafy veggies, molasses, baked beans, nuts and nut butters, oranges, figs, apricots, tofu made with calcium sulphate and sardines with the bones.

Here’s how to fit calcium into your busy day and get your 700mg:

Breakfast: An orange and a 2 egg omelette (102mg)
Morning snack: 12 almonds, a glass of milk and a fig (359mg)
Lunch: About 90g of fresh salmon with bones and 1/2 cup of cooked broccoli (227mg)
Dinner: 90g lean meat and 1 cup of kale (100mg)

Total: 788mg!

Of course, you really don’t have to count the milligrams of calcium you’re getting; just make sure to enjoy a varied diet. And don’t forget your dose of sunshine vitamin – vitamin D helps the body regulate calcium and phosphate absorption!

Dairy products to shelve during pregnancy

Because of the way they’re prepared, some cheeses and unpasteurised milk can cause food borne illnesses. For more information read our guide on food safety in pregnancy.

Foods that inhibit absorption of calcium

  • Foods rich in sodium: Most processed foods and meats.
  • Oxalates: These are found in most green leafy veggies, sweet potatoes, okra, beets, soy products, chocolate and tea.
  • Phytates: High fibre foods like whole-grain products, wheat bran, beans, nuts and seeds are rich in phytates.

Ditching processed salty foods would definitely benefit you and your baby. However, you don’t need to avoid eating foods rich in oxalates and phytates – instead, consume several servings of calcium-rich foods and this will offset the small amount of calcium that isn’t be absorbed.

Calcium supplements: do you need them?

Maybe, maybe not – it all depends on whether you were calcium deficient prior to pregnancy and if you’re having trouble meeting your RNI with food alone. Before popping calcium pills, make sure to talk to your GP first and have a dietitian review your current diet.

An excessive calcium intake (from supplements) can harm your baby: some babies fail to thrive, while others suffer from various symptoms ranging from mild constipation, muscle weakness to severe seizures. According to studies, excess calcium intake can also hinder the absorption of other minerals such as iron, magnesium, and zinc which are also essential for both mother and child.

Tips on choosing calcium supplements

If your GP suggests a supplement, enquire which brand would best suit your needs. For instance, pills that contain calcium carbonate are readily absorbable and won’t cause discomfort. But if you’re taking medication to reduce your stomach acid or if you suffer from poor digestion, calcium citrate may be a better option. Your GP may even prescribe you a calcium supplement that contains vitamin D.

Also, because your body can only absorb about 500mg of calcium at a time, if your prescribed dose is greater than that, you may want to split it. These supplements are usually taken with meals.

Busting calcium myths during pregnancy

You only need to watch your calcium intake during the 3rd trimester

You may come across articles saying that calcium is essential only during the last trimester, the period during which Junior’s skeleton is rapidly developing. It’s true that 80% of foetal calcium accretion occurs during the 3rd trimester and that the calcium ‘transfer’ to Junior shoots from 50mg/day during the 2nd trimester to 250mg/day during the 3rd trimester. However, to meet this high demand at the end of gestation, your body must have enough calcium in stock early during the pregnancy. That’s why you need to start getting enough calcium as from the moment you get the good news or ideally as soon as you consider trying for a baby.

In case of inadequate calcium intake, the foetus will take what it needs from the mother – this can lead to osteoporosis or cavities

Studies suggest that women lose about 3 to 6% of their bone mass during pregnancy. However, this ‘lost’ bone is replaced within a few months after pregnancy and the bone density returns to normal. Some women even experience an increase in bone density!

No link has been found between osteoporosis and calcium loss during pregnancy. Researchers explain that the low postpartum bone mass observed among some women cannot be attributed to an inadequate diet or to foetal calcium needs but to:

  • Pre-pregnancy low bone density;
  • Medications like heparin, anticonvulsants, and corticosteroids;
  • Certain diseases.

And no, your baby won’t take calcium from your teeth. The cavities observed by new mothers are often due to an increased consumption of sweets, changes in oral hygiene and vomiting.

Calcium supplements can reduce your risks of pregnancy-induced hypertension (PIH) and preeclampsia

Taking a supplement can offer some protection if you’re at risk of these conditions. Women who are the most vulnerable to PIH and preeclampsia are:

  • Teenagers;
  • Women over 35 years old;
  • Women pregnant for the first time;
  • Women with multiple pregnancies;
  • Women with pre-existing conditions like diabetes, hypertension, renal disease, or obesity;
  • Women with a family history of PIH or pre-eclampsia.

Looking for some extra bone protection?

Consider weight bearing exercises such as stair climbing, aerobics, tennis or jogging on a treadmill. Talk to your GP before starting any new exercise regime.


    Black et al (2000) A detailed assessment of alterations in bone turnover, calcium homeostasis, and bone density in normal pregnancy. J Bone Miner Res. 15(3):557-563.

    Hacker AN, Fung EB and King JC (2012) Role of calcium during pregnancy: maternal and fetal needs. Nutr Rev. 70(7):397-409.

    Kovacs CS (2001) Calcium and bone metabolism in pregnancy and lactation. J Mammary Gland Biol Neoplasia. 10(2):105-118.

    Lamke B, Brundin J and Moberg P (1977) Changes of bone mineral content during pregnancy and lactation. Acta Obstet Gynecol Scand. 56(3):217-9.

    Prentice A (1994) Maternal calcium requirements during pregnancy and lactation. Am J Clin Nutr. 59(2 Suppl):477S-482S

    Prentice A (2000) Calcium in pregnancy and lactation. Annu Rev Nutr. 20:249-72.