Abstract: Calcium is an essential mineral for overall health, particularly throughout pregnancy. This mighty mineral is crucial for various bodily functions, including muscular contraction, hormone signaling, and enzyme function, and is most commonly known for its role in bone health. Inadequate calcium intake during pregnancy can have longer-term health effects for both mother and baby. Calcium deficiency is associated with an increased risk of preeclampsia, hypothyroidism, preterm birth, and low birth weight. Additionally, inadequate calcium during pregnancy can lead to osteoporosis later in life. For your baby, low calcium is associated with; poor bone structure, both at birth and later in life; slow heart rate; tremors; and even schizophrenia later in life. Adequate calcium is also crucial to support the longevity and health of breastfed infants. There is a risk of calcium toxicity, particularly from supplementation, so it is essential to be mindful of the type and how much calcium you are intaking.

What Is Calcium And Why Do I Need It?

Calcium is the most abundant mineral in the body. It is essential for muscle contraction, bone formation, enzyme function, nerve transduction, and hormone signaling. Other than dairy products, calcium-rich foods include spinach, chia seeds, almonds, and salmon. Since your body can absorb greater amounts of calcium within the small intestine when pregnant, recommended intake does not change.

Back in week 22, we learned:

The role of calcium during pregnancy
The interaction between calcium and other nutrients such as iron and vitamin D
Ways of getting calcium both through diet and supplementation during pregnancy
Recommendations for calcium intake during pregnancy

This week we will delve into calcium’s role during late pregnancy and postpartum. We will learn how calcium during this later part of pregnancy:

Effects on the development of bone and teeth
Impacts thyroid function
Influences the risk of preeclampsia
Supports breastfeeding

Did you know? A women's intestinal absorption of calcium is about 50% higher in early pregnancy and almost 75% higher in late pregnancy than women not pregnant!

Calcium For Bone And Teeth Development

By now, we’ve learned that calcium, vitamin D, phosphorus, and magnesium are essential for building your baby's bones. Almost all (98%) of calcium in the body is stored in the bones. The extra mineral is stored in the mother's bones throughout early pregnancy, where you absorb more calcium. Then, later in pregnancy, there is a dramatic increase in calcium that goes from the mom across the placenta to the baby. In fact, research finds that in the final weeks of pregnancy, more than 300 mg of calcium is transported to the fetus per day!

Did you know? Immediately after birth, fetal calcium levels decline significantly, then stabilize within 24 to 48 hrs. This is due to the cut-off of immediate calcium from the placenta.

Calcium homeostasis is a complex process involving calcium and three hormones—parathyroid hormone, calcitonin, and calcitriol, the active form of vitamin D. To maintain calcium homeostasis, your body undergoes a process called bone remodeling. Bone remodeling is a process where old bone tissue breaks down, bone resorption, and new bone forms through ossification; this occurs throughout your entire life. Osteoclasts are the cells that activate the resorption or breakdown, while osteoblasts trigger ossification or the formation of new bone.

When younger, the bone remodeling process has a fairly even trade-off of tissue breakdown to new tissue formation. However, after about 25 years old, your body stops the ossification, thus halting new tissue growth.

Important fact: Pregnant women younger than age 25 are still actively depositing minerals in their bones as they are approaching ‘peak bone mass.’ This means that just like your baby’s bones are growing, yours are too. Therefore, proper calcium intake is vital for this age group!

Although your bones stop growing at this age, calcium is just as crucial for maintaining bone health, along with supporting all of the other functions of calcium, such as nerve transduction, hormone signaling, and muscular contraction.

Excessive supplementation can lead to build-up in soft tissue and kidneys, leading to the formation of kidney stones. There is inconclusive evidence supporting calcium supplementation and bone loss since large doses are found to have these adverse effects listed above. Because of this, a tolerable upper limit has been established for calcium:

2000mg for all adults
2500 for pregnant women > 18 years old
3000mg for women who are 18 or younger and pregnant.

Did you know? The skeleton of a newborn baby contains approximately 20–30 g of calcium.

How Does Calcium Influence Thyroid Function?

The regulation of calcium involves the parathyroid gland, the bone, the kidneys, and the blood. Low blood calcium signals the parathyroid gland to release parathyroid hormone (PTH) into the blood. The PTH then does most of the work, binding to bone cells to trigger resorption, acting on kidneys to synthesize the active form of vitamin D, and promoting calcium reabsorption from the kidneys into the blood.

Hyperparathyroidism is a condition caused by higher than normal calcium levels (parathyroid glands producing too much PTH) and can lead to negative effects like osteoporosis, kidney stones, chronic fatigue, and others. The opposite problem, hypoparathyroidism, occurs when parathyroid glands do not produce enough PTH, leading to low blood calcium levels and adversely affecting muscles, nerves, and other functions.

The Relationship Between Low Calcium And Preeclampsia

Preeclampsia is a condition that involves both high blood pressure and elevated protein in the urine. It typically appears after 20 weeks of pregnancy and will disappear a few days after birth. It Is the leading cause of preterm birth and accounts for about 15% of infants who are growth restricted.

Not only does this condition influence birth outcomes, but also significantly affects the mother's health. This condition affects almost all of the mother's organs, including the brain, heart, liver, and kidneys. If preeclampsia progresses, it can evolve into a more serious condition called eclampsia which could result in seizures or even death.

Researchers have found a lower prevalence of preeclampsia in countries with a diet high in calcium, such as Ethiopians and Mayans from Guatemala. The Dietary Guidelines for America 2020-2025 identifies low calcium as a public health concern for Americans. This aligns with the fact that most Americans also do not meet the recommended intake of fruits and vegetables.

As mentioned above, low calcium also influences thyroid function. Low intake may stimulate the secretion of parathyroid hormone, which can lead to vasoconstriction and retention of sodium and fluid. These physiological changes can lead to the development of preeclampsia.

Choosing To Breastfeed? Calcium Is An Essential Nutrient For Breastfed Babies

If you choose to breastfeed, many micronutrients, macronutrients, and phytochemicals within your diet can support your baby's health. Calcium is one of those essential micronutrients that help your baby's growth, development, and longevity.

Studies find that, on average, about 200 mg of calcium/day is secreted into breast milk, with some women secreting as much as 400 mg/day! Interestingly, research finds that women who take calcium supplements are more likely to breastfeed than those who do not supplement. That being said, it is essential to remember to risk of toxicity.

While breastfeeding, calcium intake is just as important for you as your baby. Researchers have found that women lose 3 to 5 percent of their bone mass while breastfeeding.

Summary

Calcium is an essential mineral for overall health, particularly throughout pregnancy. This mighty mineral is crucial for various bodily functions, including muscular contraction, hormone signaling, and enzyme function, and is most commonly known for its role in bone health. Inadequate calcium intake during pregnancy can have longer-term health effects for both mother and baby.

Calcium deficiency is associated with an increased risk of preeclampsia, hypothyroidism, preterm birth, and low birth weight. Additionally, inadequate calcium during pregnancy can lead to osteoporosis later in life. For your baby, low calcium is associated with; poor bone structure, both at birth and later in life; slow heart rate; tremors; and even schizophrenia later in life. Adequate calcium is also crucial to support the longevity and health of breastfed infants.

There is a risk of calcium toxicity, particularly from supplementation, so it is essential to be mindful of the type and how much calcium you are intaking. Additionally, calcium supplements have not been proven to support bone mass effectively. Eating various calcium-rich foods such as spinach, beans, nuts, seeds, and kiwi will help you and your baby's health!

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