Plasma thyrocalcitonin and parathyroid hormone concentrations in early neonatal hypocalcaemia.

Romagnoli, Costantino; Zecca, Enrico; Tortorolo, Giuseppe Gio Batta; Diodato, A.; Fazzini, Gerolamo; Sorcini-Carta, M

doi:10.1136/adc.62.6.580

Cited by 13 publications

(4 citation statements)

References 13 publications

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“…Early neonatal hypocalcemia, most frequent in preterm infants (2 1) has been attributed to transient hypoparathyroidism (1 7-1 9, 2 1). Some studies have cast doubt on this hypothesis since elevated PTH levels have been observed in hypocalcemic preterm infants (9)(10)(11)(12)(13)(14)(15)(16). Other authors (17)(18)(19)(20) again reported a lack of rise of PTH in preterm infants in response to hypocalcemia.…”

Section: Discussionmentioning

confidence: 99%

Intact Parathyroid Hormone Levels during Pregnancy, in Healthy Term Neonates and in Hypocalcemic Preterm Infants

Saggese¹,

Baroncelli²,

Bertelloni³

et al. 1991

Acta Paediatrica

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We measured parathyroid hormone levels in pregnant and nonpregnant women and at 1, 2 and 5 days of life in healthy term neonates and in hypocalcemic preterm infants using a new immunoradiometric assay which measures only biologically active intact parathyroid hormone and by a mid-molecule parathyroid hormone radioimmunoassay. During pregnancy intact and mid-molecule parathyroid hormone levels did not show any modification and were not different from parathyroid hormone levels of nonpregnant age-matched controls. Serum calcium and phosphorus levels did not vary during each trimester of pregnancy. In cord serum intact and mid-molecule parathyroid hormone values were low in both term and preterm infants. In term neonates intact and mid-molecule parathyroid hormone levels peaked on day 1; in preterm infants intact parathyroid hormone levels peaked on day 1 while mid-molecule parathyroid hormone values peaked on day 2. Intact parathyroid hormone levels showed a more marked increase in preterm (19-fold) than in term neonates (7.5-fold) on day 1. Our data do not confirm the previously reported "physiologic" hyperparathyroidism in pregnancy. Moreover we found a normal parathyroid gland responsiveness to decreasing serum calcium levels in the first days of life in term and preterm infants. Our results suggest that measurement of intact parathyroid hormone 1-84 by immunoradiometric assay in the first days of life is a more sensitive index of parathyroid gland secretory function than the measurement of middle or carboxyl-terminal parathyroid hormone fragments allowing the detection of the dynamic changes of parathyroid hormone which occur in hypocalcemic preterm infants.

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Section: Discussionmentioning

confidence: 99%

Intact Parathyroid Hormone Levels during Pregnancy, in Healthy Term Neonates and in Hypocalcemic Preterm Infants

Saggese¹,

Baroncelli²,

Bertelloni³

et al. 1991

Acta Paediatrica

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“…A few early studies suggested that the normal high calcitonin levels in the neonate could contribute to hypocalcemia in preterm infants (558,583,595). However, subsequent studies found that gestational age at birth was a more significant determinant of neonatal calcitonin levels than the postnatal fall in serum calcium or the development of hypocalcemia (444,558,707). Therefore, the available human data suggest that calcitonin may have little role in mineral homeostasis of the neonate.…”

Section: E Human Datamentioning

confidence: 99%

Bone Development and Mineral Homeostasis in the Fetus and Neonate: Roles of the Calciotropic and Phosphotropic Hormones

Kovacs

2014

Physiological Reviews

207

188

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Mineral and bone metabolism are regulated differently in utero compared with the adult. The fetal kidneys, intestines, and skeleton are not dominant sources of mineral supply for the fetus. Instead, the placenta meets the fetal need for mineral by actively transporting calcium, phosphorus, and magnesium from the maternal circulation. These minerals are maintained in the fetal circulation at higher concentrations than in the mother and normal adult, and such high levels appear necessary for the developing skeleton to accrete a normal amount of mineral by term. Parathyroid hormone (PTH) and calcitriol circulate at low concentrations in the fetal circulation. Fetal bone development and the regulation of serum minerals are critically dependent on PTH and PTH-related protein, but not vitamin D/calcitriol, fibroblast growth factor-23, calcitonin, or the sex steroids. After birth, the serum calcium falls and phosphorus rises before gradually reaching adult values over the subsequent 24 -48 h. The intestines are the main source of mineral for the neonate, while the kidneys reabsorb mineral, and bone turnover contributes mineral to the circulation. This switch in the regulation of mineral homeostasis is triggered by loss of the placenta and a postnatal fall in serum calcium, and is followed in sequence by a rise in PTH and then an increase in calcitriol. Intestinal calcium absorption is initially a passive process facilitated by lactose, but later becomes active and calcitriol-dependent. However, calcitriol's role can be bypassed by increasing the calcium content of the diet, or by parenteral administration of calcium.

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“…These measurements were used to create the gestational age reference curve. We assumed that measurements performed within 24 h of birth reflect bone status corresponding to the duration of gestation (19).…”

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confidence: 99%

Assessment of Skeletal Development in Preterm and Term Infants by Quantitative Ultrasound

et al. 2005

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Assessment of skeletal development using a nonionizing method would be desirable in critically ill preterm infants. We investigated the second metacarpus by quantitative ultrasound (QUS). Cross-sectional data were collected in 132 preterm or term infants measured within 24 h from birth and in 142 term infants up to the age of 18 mo. Longitudinal data were collected in 150 preterm infants up to the age of 14 mo. Cross-sectional data were used to devise reference curves for metacarpal speed of sound (mcSOS) and metacarpal bone transmission time (mcBTT). Both parameters increase during the last trimester of gestation. After birth, mcSOS declines up to the 6 mo and then increases up to 18 mo of life. McBTT values remain stable after birth. At birth, QUS values of preterm infants are lower than those observed at birth in term infants. In the longitudinal study, mcSOS showed a trend similar to that observed among term infants, nevertheless, values are lower up to 4 -6 mo of life. Among preterm infants, mcBTT increases until it reaches values observed in term infants. Preterm infants in their first months of life have lower QUS values compared with term infants of same weight or length. This study demonstrates that it is possible to follow skeletal development and maturation by QUS in preterm infants. More specifically, the mcBTT values may provide information on bone tissue that is independent of length and weight of the preterm infant. The method here described is safe, repeatable, and reliable. The incidence of congenital disorders of skeletal development is estimated to be about 1 in 4000 births (1). Most of them are clinically apparent at birth. Numerically more prominent are neonates suffering from intrauterine growth retardation. Further, in infants born before 28 wk of gestation and/or weighing less than about 800 g at a few weeks after birth, a temporary postnatal scarcity of bone tissue may appear. This is called osteopenia of prematurity, and may lead to spontaneous fractures (2,3). Presently, DXA is the most extensively used method for the assessment of bone mineralization (4). DXA has been used to measure bone mineral content in newborns (5-7). In longitudinal studies, DXA suffers from important limitations such as cumulative radiation dose and motion artefacts; a further limitation to the use of DXA is represented by the fact that mineral accretion and bone growth are not parallel (3). In these infants, the assessment of skeletal development at birth and in early infancy using a nonirradiating method would be desirable.QUS technique has been used for the past 10 y to assess bone tissue in postmenopausal osteoporosis (8 -11). Recent studies have shown that ultrasound can be utilized to assess bone mineral disorders in children and neonates. In preterm and term newborns, radius, humerus, and tibia were used as sites of measurement (12-16). Bearing in mind the special caution demanded by critically ill and very small infants, we sought an ultrasound method and site of measurement to achieve reliable and repe...

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Plasma thyrocalcitonin and parathyroid hormone concentrations in early neonatal hypocalcaemia.

Cited by 13 publications

References 13 publications

Intact Parathyroid Hormone Levels during Pregnancy, in Healthy Term Neonates and in Hypocalcemic Preterm Infants

Intact Parathyroid Hormone Levels during Pregnancy, in Healthy Term Neonates and in Hypocalcemic Preterm Infants

Bone Development and Mineral Homeostasis in the Fetus and Neonate: Roles of the Calciotropic and Phosphotropic Hormones

Assessment of Skeletal Development in Preterm and Term Infants by Quantitative Ultrasound

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