Normal blood calcium levels in newborns

Most newborns will receive a full-body physical examination right after they are born. This is mainly to see whether the child's organs are developing normally. Sometimes it may be necessary to test the child's blood calcium to see if the child needs calcium supplementation, because if the newborn is calcium deficient, it is particularly easy to cause rickets. So what is the normal value of blood calcium in newborns?

Calcium balance mainly depends on the regulation of parathyroid glands and calcitonin. If the regulatory function is immature or abnormal, or the fetus stores insufficient calcium or takes in too much phosphorus after birth, it can cause hypocalcemia. The specific causes are as follows:

1. Temporary suppression of parathyroid function

Early hypocalcemia occurs within 2 days after birth and is mostly due to temporary suppression of parathyroid function. Because in the late pregnancy, the amount of calcium in the maternal blood that is actively transferred to the fetus through the placenta increases, parathyroid function is inhibited. Low birth weight infants, asphyxia and newborns with respiratory distress syndrome have poorer parathyroid function and less calcium reserves than full-term normal newborns. Some people have higher levels of calcitonin in their blood within a few days after birth, which is also related to hypocalcemia. The blood calcium level of patients in the early stage is often lower than 1.75mmol/L.

2. Cow milk feeding

Late hypocalcemia occurs 3 days after birth, with the peak at the end of the first week. It is more common in newborns fed with cow's milk. Due to excessive phosphorus intake and imbalance in the calcium-phosphorus ratio, calcium absorption is impaired, resulting in low blood calcium. The blood calcium level is usually lower than 2.00mmol/L.

3. Hypocalcemia caused by congenital parathyroid insufficiency in a few cases

The onset may be early or late, and the symptoms may last for a long time, up to more than 3 weeks. However, in most children, the development of parathyroid function can catch up with that of normal infants as they grow older, so the condition is temporary.

4. Occasionally, pregnant mothers may suffer from hyperparathyroidism or adenoma

The mother has hyperparathyroidism and increased blood calcium, which inhibits the fetal parathyroid function and causes persistent hypocalcemia in the newborn after birth. The mother is often asymptomatic, and hypocalcemia in the neonate is a clue to the diagnosis of maternal hyperparathyroidism or a tumor.

Clinical manifestations

Symptoms vary in severity, mainly manifested as increased neuromuscular excitability, irritability, startles, hand and foot cramps, tremors and convulsions. During an attack, there may be an increase in heart rate or cyanosis, and severe symptoms include laryngeal spasm and respiratory arrest. The digestive system may cause vomiting and bloody stools. The child is generally in good condition between attacks, but has slightly higher muscle tone and increased tendon reflexes.

examine

1. Blood calcium decreases and blood phosphorus increases.

2. Electrocardiogram: prolonged QT time.

diagnosis

1. The mother may have diabetes or gestational hypertension during pregnancy, and premature babies and those with a history of asphyxia are more common.

2. The disease usually occurs a few hours to 2 days after birth, with symptoms such as restlessness, startle, limb tremors, laryngeal spasm, convulsions, etc. Children are generally in good condition between attacks.

3. Blood calcium is lower than 1.75 mmol/L (7 mg/dl) or free calcium is lower than 0.9 mmol/L (3.5 mg/dl).

treat

1. Calcium therapy is very effective. Give intravenous or oral calcium therapy to maintain blood calcium within the normal range. For neonatal late hypoemia, it is advisable to switch to breast milk or formula feeding.

2. Convulsions caused by hypoparathyroidism are difficult to control. In addition to calcium supplements, large doses of vitamin D or drugs that help urinary phosphorus excretion can be added. Blood calcium needs to be monitored during treatment to prevent excessive blood calcium from depositing in the kidneys.

3. Hypocalcemic convulsions may be accompanied by hypomagnesemia, which requires monitoring and magnesium supplementation.