How to get enough calcium in pregnancy

Pregnancy does not raise your calcium requirement, which the American College of Obstetricians and Gynecologists puts at around 1,000 mg a day for adult women. What changes is the cost of missing it, because your baby draws calcium through the placenta and your skeleton makes up any shortfall.

How much calcium does pregnancy need?

About 1,000 mg a day for most adult women, according to the American College of Obstetricians and Gynecologists, and around 1,300 mg a day for pregnant teenagers whose own bones are still laying down mass.

That surprises people. The requirement does not jump during pregnancy, because your gut absorbs calcium more efficiently once you are pregnant, which covers most of what your baby takes.

The catch is the starting point. A woman who was already low before conception has no reserve to draw on, and she is the one who ends up losing bone.

Why your baby takes calcium from you

Calcium crosses the placenta continuously, and demand climbs steeply in the third trimester as your baby's skeleton hardens. Bone, teeth, nerve signalling and muscle function all depend on it.

Your body will not let your blood calcium fall for long. It releases calcium from your bone instead, which keeps your baby supplied and quietly bills you for it.

Most of that bone loss recovers after weaning. Not all of it does, in women who never had much to begin with.

Does low calcium have symptoms?

Mostly not, and this is where the older advice on the internet goes wrong.

Because your skeleton buffers the blood level, a diet short on calcium produces no tingling, no cramps and no obvious sign. Symptoms such as numbness around the mouth, muscle spasm or twitching reflect a genuinely low blood calcium level, which is a medical problem with its own causes and needs a doctor rather than a supplement.

Leg cramps in the second and third trimesters are extremely common and are not a reliable sign of anything nutritional. Mention them at your antenatal visit anyway.

You cannot feel your way to this one. You work it out from what you eat.

Calcium-rich foods you can buy here

The Health Promotion Board's Healthier Choice Symbol appears on calcium-fortified milks and soy drinks in local supermarkets, which makes the label quicker to read when you are deciding between six cartons.

Spread it through the day rather than taking it all at one meal. Absorption is better in portions of around 500 mg or less, so a glass of milk at breakfast and tofu at dinner beats a single large dose.

Vitamin D, and why sunshine is not the whole answer

Calcium needs vitamin D to be absorbed, and Singapore is an odd case.

We sit almost on the equator with strong sun all year, and most of us spend the working day in air-conditioned offices, travel through covered walkways, and apply sunscreen when we do go out. Plenty of sun overhead does not mean plenty of sun on your skin.

Ask at your next visit. Antenatal vitamins sold here generally include vitamin D, and your obstetrician or polyclinic doctor can tell you whether you need more than that. Do not stack several supplements on your own.

Calcium, blood pressure and pre-eclampsia

The World Health Organization recommends calcium supplementation during pregnancy in populations whose dietary calcium intake is low, as part of reducing the risk of pre-eclampsia and its complications. The recommendation is aimed at populations rather than at everyone.

That distinction matters. Pre-eclampsia itself is a blood pressure disorder of pregnancy that affects the liver, kidneys and placenta. It is one of the reasons your blood pressure and urine get checked at every antenatal visit, and those visits are where it gets caught.

MediSave can be drawn on for antenatal care and delivery under the Ministry of Health's maternity arrangements, so the cost of regular checks is lower than many first-time mothers expect. Ask at your polyclinic or at KK Women's and Children's Hospital what your package covers.

Hypertension in pregnancy is defined at a reading of 140/90 mmHg or above. One high reading at home is not a diagnosis. Repeated ones need a call to your clinic within a day or two. A high reading with a bad headache, blurred vision, pain under the ribs or sudden swelling of the face or hands needs the hospital the same day.

Teeth and gums during pregnancy

Gums that bleed when you brush are common from the first trimester onwards, and the usual cause is pregnancy gingivitis rather than calcium. Hormonal changes make gum tissue react more strongly to plaque, so the same brushing that was fine last year now draws blood.

Keep brushing anyway, gently, twice a day. Stopping makes it worse. Our pieces on toothaches during pregnancy and choosing a toothpaste in pregnancy go into what helps.

If strong toothpaste sets off your nausea, or you simply prefer a fluoride-free paste while pregnant, Mama's Choice Non-Fluoride Toothpaste is made with pregnant and breastfeeding mothers in mind. It is SLS-free, with a mild mint, and regular brushing with it may help fight tooth decay. In a 2022 survey of 62 mothers, 93% said they could use it comfortably without nausea. Fluoride toothpaste is fine in pregnancy too, so this is about what you can face at 7am rather than about calcium.

When should you ask about supplements?

• Your diet contains almost no dairy, tofu, small fish or leafy greens
• You are pregnant at 18 or younger, when the requirement is higher
• You are carrying twins, or your pregnancies have been close together
• You have a condition affecting absorption, such as coeliac disease
• You have had pre-eclampsia before, or your blood pressure is being watched
• Numbness, tingling or muscle spasm, which needs assessment rather than a shop

Bring the actual packet to the appointment. Many antenatal multivitamins already contain calcium and vitamin D, and doubling up is a real risk once a well-meaning relative starts buying tubs of supplements for you.

Our guide to foods to avoid during pregnancy covers the other half of the question, and staying comfortable through pregnancy deals with the aches that calcium will not fix.