Calcium homeostasis during pregnancy and lactation: role of vitamin D supplementation

Pregnancy and lactation cycle is a period of considerable strain on maternal calcium homeostasis. A number of adaptive mechanisms involve increased intestinal calcium absorption, renal calcium conservation and changes in bone metabolism. These adaptations are mediated through changes in the secretion of various calciotropic hormones [1,25(OH)2 D3, parathormone, and calcitonin]. In all of these adaptive mechanisms, vitamin D is involved directly or indirectly. Now, it is being realized that not only dark-skinned but also even Caucasian women tend to go into vitamin D deficiency during pregnancy. Adverse health outcomes such as preeclampsia, low birth-weight, neonatal hypocalcemia, poor postnatal growth, bone fragility, and increased incidence of autoimmune diseases have been linked to low vitamin D levels during pregnancy and infancy. Vitamin D deficiency seems to be a public health problem even in 2018. Most of the experts in the field are convinced that women need extra amounts of vitamin D during pregnancy and lactation. The amount of vitamin D that is required for optimum calcium homeostasis in this phase of life is still controversial. Studies are under way to establish the recommended daily doses of vitamin D in pregnant and lactating women.