Obstetrics and gynecology expert: Encourage pregnant and breastfeeding women to supplement calcium appropriately

During pregnancy and lactation, calcium is transferred from the mother's body to the fetus for growth and to the infant through breast milk. When calcium reserves are insufficient, the body mobilizes calcium from bones to meet fetal needs.

Calcium supplementation presents a perplexing dilemma: Expectant mothers worry that inadequate calcium intake may hinder fetal development, yet fear excessive supplementation could burden their bodies. Additionally, many grassroots obstetricians harbor uncertainties, such as determining appropriate calcium dosage and selecting suitable supplements for pregnant women. To address these concerns, our editorial team had the privilege of interviewing Professor Liu Xinghui, Director of Obstetrics at West China Second University Hospital, Sichuan University, seeking insights on calcium nutrition during pregnancy.

Editor: During pregnancy and lactation, women undergo significant changes in calcium balance. How do these stages alter calcium absorption, distribution, and excretion? What specific calcium intake requirements exist?

Professor Liu: Pregnancy and lactation cause calcium transfer to the fetus and milk production. When calcium reserves are insufficient, the body mobilizes calcium from bones to meet fetal needs. While typical calcium absorption rates are 30-40%, absorption increases in pregnant and lactating women, though still limited. Due to pregnancy and lactation, their calcium requirements significantly exceed those of non-pregnant women: 800mg/day in early pregnancy, and 1000mg/day during mid-to-late pregnancy and lactation. Thus, routine calcium supplementation is essential throughout pregnancy.

Editor: Given the increased intake requirements, calcium supplementation is crucial for pregnant and lactating women. With improving living standards, why does actual calcium intake still fall short of recommendations? Is it due to low awareness of supplementation?

Professor Liu: Dietary surveys in China indicate that daily calcium intake and absorption from food sources averages around 400mg—nearly half of the required amount. Therefore, healthcare providers should encourage and recommend calcium supplementation for pregnant and lactating women. These supplements should contain vitamin D or be taken alongside vitamin D to enhance calcium absorption. While awareness of calcium supplementation among pregnant women has improved significantly compared to the past, certain misconceptions persist. Many women worry that calcium supplementation may cause placental aging or even lead to fetal skull hardening and difficult labor. In reality, these concerns are unfounded.

Editor: For women whose calcium intake is significantly below recommended levels, what immediate and long-term risks does calcium deficiency pose to both mother and fetus?

Professor Liu: For the mother, decreased serum calcium levels can cause severe cramps. Thus, calcium deficiency during pregnancy leads to rapid mobilization of calcium from bones to replenish blood calcium. During delivery, this increases the risk of uterine atony and postpartum hemorrhage. Additionally, it accelerates the onset of maternal osteoporosis and tooth loosening, while raising fracture risk. Recent studies also indicate that calcium deficiency during pregnancy significantly increases the incidence of gestational hypertension, preeclampsia, and eclampsia. Therefore, high-risk individuals should supplement calcium early in pregnancy to prevent these conditions. From the fetal perspective, maternal calcium deficiency often leads to intrauterine growth restriction, increasing the risk of fetal distress, preterm birth, and neonatal asphyxia. Insufficient calcium in maternal breast milk can cause slower growth rates compared to peers, weakened immune function, and increased rates of intellectual disabilities in infants. Additionally, these children face heightened risks of cardiovascular disease and diabetes in adulthood, creating a domino effect of adverse health outcomes.

Editor: What calcium-rich foods with good absorption are suitable during pregnancy and lactation? Which types of calcium supplements should be chosen?

Professor Liu: Milk and dairy products are high-calcium foods, with roughly 1mg of calcium per 1ml of milk. However, daily milk intake should not exceed 500ml to avoid excessive fat and protein consumption. Sesame seeds are also high in calcium, and grinding them into powder improves absorption. However, sesame seeds are rich in oils, so excessive consumption may lead to excessive energy intake. Soy products also contain significant amounts of calcium. The key to dietary intake is moderation and variety. Calcium supplements are generally recommended in the form of calcium carbonate + vitamin D3, which is safe and effective. Common calcium gluconate supplements contain relatively low calcium per small bottle (10ml). An adult needing 600mg of calcium would require approximately 7 bottles to meet the requirement. Healthcare professionals are advised to refer to the “Dietary Reference Intakes for Chinese Residents” and the “Chinese Dietary Pyramid” when guiding calcium intake for pregnant and lactating women, providing personalized and effective guidance based on individual circumstances. Calcium Nutrition Recommendations for Pregnant and Lactating Women

Editor: Many mothers worry that excessive calcium supplementation may cause kidney stones. What is your perspective on this concern? Professor Liu: All current research indicates no direct link between kidney stones and calcium supplementation. However, kidney stone patients typically have underlying conditions where metabolic disorders lead to calcium oxalate accumulation, resulting in kidney stones.