Calcium

​In this article, we’ll discuss the optimal calcium ranges in pregnancy, the causes behind abnormal levels, and how physiological changes during pregnancy influence these values. A solid understanding of calcium’s role helps ensure comprehensive maternal and fetal health support.

Calcium Testing

The calcium test measures the concentration of total calcium in the blood. It is an analyte on the basic and comprehensive metabolic panels (CMP). 

Calcium metabolism and function are regulated by parathyroid hormones, calcitonin, and vitamin D3, as well as the bones, kidneys, and small intestines.

99% of all the body’s calcium is stored in the bones; <1% is found in the bloodstream.

Calcium is found in the bloodstream in three forms: free ionic calcium, albumin-bound calcium, and bicarbonate (and other anions)-bound calcium. 

• Complexes: calcium-bound to citrate, oxalate, carbonate, and phosphate
• Ionized: free ionic calcium
• Protein-Bound: mostly bound to albumin and some to globulin

The kidneys filter Ionized and complex calcium, while protein-bound calcium is not. 

Calcium in Pregnancy

Calcitonin increases in the first trimester and remains elevated throughout pregnancy. Parathyroid hormones are suppressed in the first trimester but return to normal ranges in the third trimester. The placenta increases the production of calcitriol, which increases calcium absorption in the gut by two or threefold.

​Serum-ionized calcium levels are unchanged in pregnancy, but there is a decrease in serum total calcium due to a decrease in serum albumin and the bound fraction of calcium, brought about by volume expansion in pregnancy.

For most women, serum calcium levels typically normalize by around six weeks postpartum.

High Calcium in Pregnancy

In women with hyperparathyroidism, serum calcium levels are usually only mildly elevated during pregnancy. A significant proportion of cases go undiagnosed. Mild hypercalcemia in gestational hyperparathyroidism is generally not associated with an increased risk of obstetrical complications.

​However, severe maternal hypercalcemia is associated with life-threatening complications for both mom and baby. 

Most Common Causes of High Calcium in Pregnancy

• Dehydration
• Vitamin D Overdose
• Hyperthyroidism
• Heavy Metal Exposure
• Metabolic Acidosis
• Parathyroid Hyperfunction
• Certain Medications (diuretics)

Low Calcium in Pregnancy

The most common cause of hypocalcemia in pregnancy is poor oral calcium intake and vitamin D3 deficiency. 

In some countries, hypocalcemia can be as high as between 60% and 70% of pregnancies. There is also a link between low calcium and gestational hypertension. 

There is an association between ionized calcium levels and the severity of postpartum hemorrhaging.

Most Common Causes of Low Calcium in Pregnancy

• Hypothyroidism
• Metabolic Alkalosis
• Low Progesterone
• Nutritional Deficiencies (vitamin D, magnesium)
• Low Protein Diet
• Low Albumin (Proteinuria) 
• Poor Protein Metabolism

Interested in functional lab analysis? 

​My advanced course is tailored for maternity care!

Click here for more!

---

Copyright © 2024 Functional Maternity, all rights reserved.

Medical Disclaimer:
This content is for educational purposes only and is intended for licensed medical professionals. It is based on current research, subject to change, and not intended to diagnose, treat, or prevent any medical condition. This information does not replace consultation with a qualified healthcare provider. Seek professional medical evaluation and treatment from a licensed provider. Use of this information is at your own risk.

---