The impact of fetal size and length of gestation on 6‐sulphatoxymelatonin excretion in adult life

Abstract

Recent studies have shown that intrauterine growth retardation or fetal distress in human infants is associated with a pronounced reduction in melatonin secretion during the first 3 months of life. It is not known whether these associations persist beyond infancy. We have therefore examined the relationship between birthsize and melatonin secretion in 159 men and women aged 20, born in Adelaide, South Australia. Melatonin secretion was estimated by analysing the overnight urinary excretion of 6-sulphatoxymelatonin. The overnight excretion ranged from 1.7 to 128.9 nmoles/subject, was higher in women than in men (46.5 vs 34.1 nmoles, P = 0.003) and was significantly negatively correlated with the body mass index (P = 0.006). Excretion correlated with both birthweight and ponderal index at birth (P = 0.04 and P = 0.01 respectively after adjustment for gestational age) and also fell with increased duration of gestation (P = 0.007). The effects of adult body mass index added to that of low birthweight in predicting 6-sulphatoxymelatonin excretion. These data suggest that urinary 6-sulphatoxymelatonin excretion was impaired in adults who were growth restricted prenatally or were delivered after 40 weeks gestation.

Being Born Too Small and Too Early May Alter Sleep in Childhood

“…13 Although human data are scarce, studies suggest that FGR may alter the maturation of sleep circadian rhythms in neonatal life and based on actigraphy data, sleep efficiency (SE) later in life. 14 Compounding these sleep disturbances, being born preterm, whether the infant is growth restricted or not, is associated with altered maturation of sleep in infancy. 15 This is of particular concern, as sleep is the main behavioral state during the neonatal period and is known to be important for neurological development.…”

Do Birth Variable Data Predict Melatonin Production in 8- to 9-Year-Old Children? Analysis of Excreted 6-Sulfatoxymelatonin

“…The comparison between the children studied here and the young adults studied by Kennaway et al [4]relies on the stability of melatonin production within this period of life. Waldhauser et al [11]have taken a single blood sample around midnight from 367 persons at the age of 3 days up to 90 years and shown that melatonin levels are at maximum at the age of 1–3 years and decrease then by about 80 % until the age of 15–20 years.…”

“…Kennaway et al [4]assumed that prenatal events determine the great inter-individual variability of melatonin production even in adults. To verify this they related overnight urinary excretion of aMT.6S from 159 young adults (20 years) to actual body size (height, weight, BMI) and to gestational age and body size at birth (height, weight, PI).…”

“…Some authors assume that this variability is determined genetically [3], others suppose a decisive influence of environmental factors operating during intrauterine life. To determine a possible prenatal origin, Kennaway et al [4]related overnight urinary excretion of the melatonin metabolite 6-sulfatoxymelatonin (aMT.6S) of 159 adults aged 20 years to birth variable data and found significant correlations with the ponderal index at birth. As melatonin production remains stable during childhood, adolescence and early adulthood [5]similar results were expected for daily aMT.6S excretions of 147 children aged 8 or 9 years.…”

Seasonal fluctuations in birth weight and neonatal limb length; does prenatal vitamin D influence neonatal size and shape?

“…Future studies should examine seasonal fluctuations in maternal weight gain in order to explore these factors. There is also evidence suggesting that the maternal environment may influence the dprogrammingT of the fetal suprachiasmatic nucleus, which is involved in the generation of circadian rhythms [36,37]. Because of the links between melatonin, growth hormone and bone remodelling [38], these mechanisms require further scrutiny.…”