Calcium supplements in pregnancy

Key points about calcium supplements in pregnancy

  • Some pregnant people are at risk of developing a serious high blood pressure condition called pre-eclampsia.
  • If you're at risk of pre-eclampsia, especially if you don't have enough calcium in your diet, taking calcium supplements every day during pregnancy reduces your risk and increases your chance of having a healthy baby. 
  • Find out how to take it safely and possible side effects.
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Calcium has been found to be helpful for people who are at risk of developing preeclampsia. Pre-eclampsia is a condition in pregnancy that can cause you and your baby to become seriously ill. One of the common symptoms is high blood pressure. Read more about pre-eclampsia.

  • Getting calcium from your diet is the best way to ensure you get enough calcium. The best sources of calcium are low-fat milk and milk products as the calcium in milk is easily absorbed by the body. Calcium is also found in other foods, including dark green leafy vegetables, almonds, sardines, salmon with bones and tofu.
  • Although getting calcium from your diet is preferred, there may not be enough calcium in your diet to prevent pre-eclampsia and taking calcium tablets may be necessary.

Note: Low-dose aspirin has also been found to be beneficial for pregnant people who are at risk of developing preeclampsia. Read more about low dose aspirin in pregnancy

Risk factors for pre‑eclampsia

The chance of developing pre-eclampsia is higher if you have:

  • certain medical conditions, eg, high blood pressure, diabetes, kidney disease, antiphospholipid antibodies or systemic lupus erythematosus (SLE)
  • had pre-eclampsia before
  • a sister or mother who had pre-eclampsia
  • had in vitro fertilisation (IVF).

  • Calcium supplements to prevent pre-eclampsia are usually given as calcium tablets (Calci-Tabs or calcium carbonate).
  • The dose to prevent pre-eclampsia is 2 tablets once a day, during pregnancy.
  • Swallow the tablets whole with a glass of water.
  • It is best to take your calcium tablets with food.
  • Calcium tablets can interfere with the way your body absorbs other medicines so you may need to take these at a different time to your calcium – ask your pharmacist for advice.

Note: Do not take multi-vitamins, vitamin C, vitamin E or other supplements, such as fish oil or magnesium if you are at risk of pre-eclampsia.

Calcium tablets can cause stomach upset and constipation. Tell your doctor if these side effects bother you.

Also tell you doctor if you get signs of too much calcium, eg, nausea, headache, confusion and weakness.

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

Last reviewed: