Why calcium is essential in pregnancy

Posted on 11 October 2016

Dr Olufemi Owolabi, an obstetrician and gynaecologist at Mediclinic Ermelo, says your diet and intake of Vitamin D and calcium in pregnancy can impact both your and your baby’s bone mass – and insufficient intake results in an increased risk of osteoporosis later in life.

‘A full-term baby accumulates 30 grams of calcium in bone mass, so the mother needs to ensure she gets an adequate amount to maintain her own bone strength and provide for the baby too,’ says Dr Owolabi. ‘This is very important for a healthy pregnancy and delivery.’

Calcium in pregnancy: how much is enough?

‘Calcium is an essential nutrient,’ says Dr Owolabi, explaining that 99% of the body’s calcium is found in the bones and teeth. ‘Calcium helps with the skeletal development of the foetus, and also plays a role in neuromuscular function and blood coagulation. During pregnancy, calcium supplementation can reduce the risk of high blood pressure and premature labour.’

Vitamin D in pregnancy

‘Vitamin D is essential for calcium homoeostasis – the regulation of the concentration of calcium ions in extracellular fluid – and maintenance of bone health,’ says Dr Owolabi. ‘Vitamin D deficiency in pregnancy has been linked to many short-term and long-term health problems in babies, including impaired skeletal growth.’

‘Calcium and Vitamin D are needed throughout pregnancy. A pregnant woman should get 1 000 to 1 300mg of calcium and 200 to 600 IU [international units] of Vitamin D per day,’ Dr Owolabi advises.

Calcium is found in the following foods:

• milk
• cheese
• yoghurt
• spinach
• okra

Vitamin D is found in:

• some dairy products, such as cheese
• orange juice
• soy milk
• cereals
• beef liver
• egg yolks

‘Sensible sunlight exposure also helps in attaining optimal levels of Vitamin D,’ Dr Owolabi adds.

Eating foods rich in calcium and Vitamin D is advisable, but the correct intake can be ensured with supplements, as food alone is often insufficient to provide the correct dosage.

Calcium in twin pregnancies

While there are increased demands for calcium and Vitamin D in the case of a twin pregnancy, increasing the recommended intake is unnecessary, says Dr Owolabi. ‘The changes in bone metabolism in women carrying twins are different from those with a single pregnancy. Early in twin pregnancies there is a large increase in bone mass, which allows women carrying twins to meet the high foetal demand for calcium during pregnancy.’

Calcium in pregnancy and osteoporosis in later life

Osteoporosis literally means ‘porous bones’ and occurs when bones start losing their protein and mineral content, particularly calcium. This leads to fragile bones with an increased susceptibility to fracture. Adequate calcium and Vitamin D intake during pregnancy can help limit later risks of osteoporosis to both mother and child. Dr Owolabi says studies show that deficiency in calcium and Vitamin D in the womb can have an effect on the bone and skeleton growth of the foetus, which could be reflected later in life.

In a small proportion of women, inadequate calcium and Vitamin D intake may lead to a weakening of the bones during pregnancy. For women already diagnosed with low bone density or osteoporosis, optimising bone health during pregnancy through supplements is very important.

Dr Owolabi says women who need to pay special attention to calcium intake during pregnancy include those who have any of these conditions:

• autoimmune disorders like rheumatoid arthritis or lupus
• surgical procedure, especially a gastrectomy (surgical removal of a part or whole of the stomach)
• endocrine problems like diabetes or hyperthyroidism
• malignancy
• stroke
• AIDS

‘Bone density starts decreasing after 35 years of age,’ adds Dr Owolabi, which makes adequate calcium and Vitamin D intake especially important for all women above this age.