SINGAPORE - You've probably heard that menopause, old age and smoking can increase your risk of osteoporosis, a condition where your bones become weak and brittle.

Pregnancy and breastfeeding may also drain your calcium stores, especially if you are not meeting your recommended daily calcium needs.

“When a pregnant or lactating mother has a low dietary calcium intake, there will be resorption of calcium from her bones,” said Dr Tan Thiam Chye, an obstetrician and gynaecologist at KK Women’s and Children’s Hospital, who co-authored The New Art and Science of Pregnancy and Childbirth.

Resorption is a process in which a substance, such as bone calcium, is broken down and then absorbed by the body.

According to Dr Tan, about 30g of calcium is transferred from the mother to the foetus during the entire pregnancy. Eighty per cent of this transferrence occurs in the third trimester (from the seventh month onwards).

By then, the mother loses about 250mg to 300mg of calcium daily to help build up her baby’s bones, on top of her daily calcium requirements.

Breastfeeding mothers also shave 280mg to 400mg off their calcium stores each day, but Dr Tan said that “daily losses as great as 1,000mg of calcium have been reported, depending on the amount of breastmilk produced”.

But with the calcium drain, are pregnant women and mothers who breastfeed for prolonged periods really more susceptible to osteoporosis later in life?

Not really, said Ms Betty Lee, a lactation consultant in private practice.

“Most women replace bone loss rapidly once the baby stops breastfeeding. Although some bone mass may be lost during breastfeeding and pregnancy, some studies suggest that the situation may reverse and actually decrease the risk of post-menopausal osteoporosis once menstruation resumes and breastfeeding is stopped,” said Ms Lee.

Plus, during breastfeeding, a woman’s body changes to adapt to the increased calcium needs by “excreting less calcium in the urine”, she added.

The same occurs during pregnancy.

“In as early as 12 weeks of the pregnancy, the ability of the digestive tract to absorb calcium is increased. There is also a decrease in the loss of calcium via the kidneys,” said Dr Tan.

Dr Tan advised pregnant and lactating mothers to supplement for calcium loss.

The Health Promotion Board recommends that pregnant and breastfeeding mothers consume 1,000mg of calcium daily. This translates to about three glasses of milk, or two to four servings of milk products daily (see box for other high-calcium foods).

Ms Yondi Lee, a holistic nutritionist at Ascension Healing, recommended calcium supplementation because “it is realistically rather difficult to obtain sufficient calcium from our diet”.

She added: “It’s an extra boost on top of our natural diet. But be sure to choose a well-balanced supplement formula with magnesium and Vitamin B for your body to absorb calcium properly.” - TODAY/ar