Prolactin, growth hormone and insulin-like growth factor-I in newborn children of smoking mothers

The relationship between serum levels of prolactin and growth hormone in the early postnatal period

BackgroundIn the neonatal period, the pituitary hormones including prolactin (PRL) and human growth hormone (hGH) are secreted in high amounts due to immature feedback mechanisms. As both hormones are secreted in part by the same somatomammotrophic cells, we investigated their relationship in newborns with respect to sex, gestational week, method of delivery, and anthropometric data.MethodsThe serum levels of PRL and hGH were measured in blood drawn from 225 newborns. The newborn data were extracted from medical records.ResultsA positive correlation was found between log-transformations of PRL and hGH (r=0.17; P=0.01; n=225), with a stronger correlation in newborns whose blood samples were taken more than 2 days after birth (r=0.42; P<0.001; n=130). Log-transformations of the PRL/hGH ratio demonstrated a positive correlation with the gestational week (r=0.39; P<0.001; n=200). Multiple regression analysis showed that 15% of the variance in the logarithm of this ratio is attributed to the gestational week.ConclusionIn newborns, serum PRL and hGH levels show a positive correlation that can be explained by common regulatory factors or a drift phenomenon. A higher gestational week is associated with a higher PRL/hGH ratio. Further studies are needed to look for possible confounders and to determine the PRL-hGH relationship in different conditions.

Associations of maternal prenatal smoking with umbilical cord blood hormones: the Project Viva cohort

BACKGROUND

Maternal smoking during pregnancy is associated with low fetal growth and adverse cardiometabolic health in offspring. However, hormonal pathways underlying these associations are unclear. Therefore, we examined maternal smoking habits and umbilical cord blood hormone profiles in a large, prospective cohort.

METHODS

We studied 978 mother/infant pairs in Project Viva, a Boston-area cohort recruited 1999-2002. We categorized mothers as early pregnancy smokers, former smokers, or never smokers. Outcomes were cord blood concentrations of IGF-1, IGF-2, IGFBP-3, leptin, adiponectin, insulin, and C-peptide. We used linear regression models adjusted for maternal pre-pregnancy body mass index (BMI), race/ethnicity, parity, education, and infant sex. We conducted analyses in the full cohort and stratified by infant sex.

RESULTS

Thirteen percent of women were early pregnancy smokers, 20% former smokers, and 68% never smokers. Infants of early pregnancy smokers had lower IGF-1 adjusted for IGFBP-3 [-5.2ng/mL (95% CI: -8.6, -1.7)], with more pronounced associations in girls [-10.7ng/mL (95% CI: -18.5, -2.9) vs. -4.0ng/mL (95% CI: -8.4, 0.4) for boys]. Early pregnancy smoking was not associated with cord blood hormones other than IGF-1. Infants of former smokers had a cord blood hormone profile similar to infants of never smokers.

CONCLUSIONS

As compared to mothers who never smoked, early pregnancy smokers had infants with lower cord blood IGF-1 which could prime adverse metabolic outcomes. This provides further reason to support smoking cessation programs in women of reproductive age.

Obesity, maternal smoking and SHBG in neonates

BACKGROUND

Sex hormone binding globulin (SHBG), a glycoprotein produced by hepatocytes that transports testosterone and other steroids in plasma, is a marker for developing metabolic syndrome and T2DM. SHBG is present in umbilical cord blood where it may be epigenetically regulated. This study was conducted to investigate whether the fetal environment, based on maternal pre-pregnancy weight, pregnancy weight gain or smoking during pregnancy, influence SHBG in newborns.

METHODS

Maternal and newborn characteristics and SHBG levels and other variables were measured in cord and day 2 heel-stick blood samples in 60 healthy full-term singleton babies (31 F, 29 M).

RESULTS

SHBG levels varied nearly fivefold among male and female newborns and were unrelated to sex, neonatal adiposity, determined by the Ponderal index and skinfold thickness, nor TNF∝ in cord blood. There were also no statistically significant associations between pre-pregnancy weight or pregnancy weight gain and newborn SHBG levels. However, cord blood SHBG was higher and insulin levels were lower when mothers were smokers, but normalized by day 2.

DISCUSSION

While SHBG levels are low in obese children and adults, and portend the development of metabolic syndrome and T2DM, our study of healthy babies born to normal women, found no connection between maternal obesity or newborn adiposity and SHBG levels in newborns. Insofar as women who smoked during pregnancy were thinner and had lower cord blood insulin levels than nonsmokers, higher SHBG in their newborns at birth might have been due to insulin sensitivity, or perhaps to an effect of smoking on placental gene expression.

CONCLUSIONS

Factors other than maternal weight and pregnancy weight gain appear to be the major determinants of SHBG in newborns. Higher SHBG levels when mothers smoke during pregnancy may contribute to overweight beginning later in childhood. Whether newborn SHBG levels predict the development of overweight and metabolic syndrome remains to be determined.

Effect of maternal smoking on cord blood estriol, placental lactogen, chorionic gonadotropin, FSH, LH, and cortisol

AIM

To determine the effect of maternal cigarette smoking on cord blood concentrations of E3, hPL, beta-hCG, FSH, LH, and cortisol.

METHODS

Hormone concentrations were measured in term neonates of 100 smoking and 100 non-smoking mothers.

RESULTS

The median E3, hPL, beta-hCG, FSH, LH and cortisol cord blood concentrations in the non-smoking mothers' offspring were 212 ng/mL, 2.00 microg/mL, 57.5 mIU/mL, 0.10 mIU/mL, 0.20 mIU/mL, and 14.3 microg/mL, respectively; in the smoking they were 163, 1.39, 45.4, 0.10, 0.20, and 25.1, respectively (P=0.008, 0.004, 0.037, 0.498, 0.286, 0.004, respectively). There was a significant but poor negative correlation between number of cigarettes/day and E3 (r=-0.163, P=0.021), hPL (r=-0.191, P=0.007), and beta-hCG (r=-0.143, P=0.044), whereas the correlation with cortisol was positive (r=0.259, P<0.0001). Multiple linear regression analyses showed that maternal smoking is a determinant of cord blood E3, hPL, beta-hCG, FSH, and cortisol concentrations.

CONCLUSIONS

Tobacco smoking is associated with a reduction in cord blood E3, hPL, and beta-hCG concentrations, whereas it is associated with increased cortisol concentrations. The disturbed endocrine equilibrium of the fetus induced by tobacco smoking could have adverse consequences on the fetus and child since fetal brain is a target organ for hormonal actions.

Maternal smoking during pregnancy specifically reduces human fetal desert hedgehog gene expression during testis development

CONTEXT

Maternal cigarette smoking during gestation increases cryptorchidism and hypospadias and reduces testis size and fertility in sons by unknown mechanisms.

OBJECTIVE

The objective of the study was to determine whether maternal smoking is linked with changes in male human fetal endocrinology, testis gene expression, and liver concentrations of cigarette smoke chemicals.

DESIGN

This was an observational study of the male fetus, comparing pregnancies during which the mothers either did or did not smoke.

SETTING

The study was conducted at the universities of Aberdeen, Glasgow, and Nottingham and Macaulay Institute (Aberdeen).

PATIENTS/PARTICIPANTS

Testes, blood, and livers were collected from 69 morphologically normal human male fetuses of women undergoing elective termination of normal second-trimester pregnancies.

MAIN OUTCOME MEASURES

Testosterone, human chorionic gonadotropin, LH, and cotinine; expression of 30 reproductive/developmental genes; liver concentrations of 16 polycyclic aromatic hydrocarbons; and Leydig, Sertoli. and germ cell numbers were determined.

RESULTS

There were no significant differences in fetal size, testis weight, cell numbers, seminiferous tubule diameter, or circulating LH and testosterone. Fetuses from smoking mothers had smoking range cotinine levels and liver concentrations of polycyclic aromatic hydrocarbons that were significant predictors of maternal smoking (P < 0.001). Only the Sertoli cell-specific gene, desert hedgehog (DHH), was significantly altered by maternal smoking (reduced 1.8-fold, P = 0.013).

CONCLUSIONS

The consequences of reduced DHH signaling in men and mice are consistent with epidemiology for effects of gestational maternal smoking on sons. Given the absence of other observed effects of maternal smoking, we concluded that reduced DHH is part of a mechanism linking maternal gestational smoking with impaired reproductive development in male offspring.

Influence of maternal smoking on neonatal aortic intima-media thickness, serum IGF-I and IGFBP-3 levels

Epidemiological studies have reported associations between a range of cardiovascular risk factors such as smoking and intima-media thickness (IMT). Some reports indicate that the maternal tobacco smoking causes disturbances of the endocrine status of the foetus. There are several potential mechanisms by which insulin-like growth factor I (IGF-I) could modify atherosclerotic processes either locally or in a systemic manner. The aim of this study was to investigate the influence of maternal smoking on neonatal aortic IMT (aIMT), serum IGF-I and IGF-binding protein-3 (IGFBP-3) levels. Aortic intima-media thickness was measured in 28 neonates whose mothers smoked during the pregnancy and 28 control neonates. Mean and weight-adjusted aIMT were significantly greater in the neonates whose mothers smoked (0.455 +/- 0.009 mm and 0.151 +/- 0.005 mm/kg, respectively) than in controls (0.403 +/- 0.029 mm and 0.118 +/- 0.014 mm/kg, respectively). Birth-weight of newborns whose mothers smoked was less than that of the controls. The decreases in serum IGF-I and IGFBP-3 observed in the infants whose mothers smoked were non-significant. Mean aIMT was negatively associated with birth-weight and IGF-I level. In conclusion, neonates whose mothers smoked have significantly increased aIMT. It might play a role in the pathogenesis of atherosclerosis in adult life.

Course of growth during the first 6 years in children exposed in utero to tobacco smoke

OBJECTIVES

Postnatal growth in children exposed in utero to tobacco smoke is not well understood. This study investigated growth during the first 6 years in children whose mothers smoked during pregnancy.

MATERIALS AND METHODS

Weight, length, and head circumference were measured annually for 6 years in 100 children in each group of smoking (study) and nonsmoking (control) mothers.

RESULTS

Weight and head circumference were significantly smaller in the neonates whose mothers smoked >or=15 cigarettes/day, but the difference disappeared by 3 years of life. Length was significantly smaller in the study neonates at birth, followed by increasing divergence from normality up to 2 years, when the mean difference of children whose mothers smoked >or=15 cigarettes/day from control children was -3.4 cm (p <or= 0.0001). Subsequently, they manifested catch-up growth ,and the difference from the controls at 3, 4, 5, and 6 years was -2.5 cm (p <or= 0.0001), -2.2 cm (p = 0.005), -2.1 cm (p = 0.013), and -1.9 cm (p = 0.055), respectively.

DISCUSSION

The delayed growth was related to smoking per se and appeared to be independent of several confounding factors. At birth, there was a significant negative correlation between the number of cigarettes smoked per day and the growth parameters studied; it remained significant up to the 6 year only for length.

CONCLUSION

Length exhibits the most persistent growth delay of the parameters studied, but catch-up growth occurs after the second year of life, and thus, intrauterine exposure to tobacco smoke seems to have no permanent effect on children's growth.

Association of secondary sex ratio with smoking and parity

OBJECTIVE

To assess the sex ratio in offspring of smoking and nonsmoking mothers in relationship to parity.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENT(S)

The authors studied 2,108 term singleton neonates born between 1993 and 2002, 665 from smoking mothers and 1,443 from nonsmoking mothers.

INTERVENTION(S)

A prospective recording of maternal age, parity and smoking status, and gender of neonates delivered over a 10-year period.

MAIN OUTCOME MEASURE(S)

Secondary sex ratio in regard to maternal smoking and parity.

RESULT(S)

The offspring sex ratio in the total sample studied was 1.09; in the offspring of smoking and nonsmoking mothers, it was 1.26 and 1.03, respectively, a statistically significant difference. In the offspring of smoking women who had parity 1, 2, and >or=3, it was 1.47, 1.35, and 0.92, whereas in those of nonsmoking women, it was 1.04, 1.00, and 1.03, respectively (the differences of the parity 1 and 2 groups between the offspring of smoking and nonsmoking mothers were statistically significant). Logistic regression analysis showed that the possibility of a boy being delivered by a mother who smoked was significantly greater in primiparous women than in women who had parity >or=3, independent of the maternal age. Conversely, parity did not affect significantly the sex ratio in the offspring of nonsmoking women.

CONCLUSION(S)

The findings suggest that among women who smoked, significantly more male than female offspring are born from primiparous women, whereas women who had parity >or=3 gave birth to more female offspring; biparous women give birth to significantly more male offspring, but the offspring sex ratio declined with the number of cigarettes when the mothers smoked >or=10 cigarettes per day.

Increased cortisol concentrations in the cord blood of newborns whose mothers smoked during pregnancy

AIM

To investigate the effect of tobacco smoke on cord blood cortisol concentrations.

METHODS

Cortisol concentrations were measured in cord blood from 211 term newborns of smoking and 211 term newborns of nonsmoking mothers; 48 and 36 newborns were delivered by cesarean section, respectively. In 16 cases, in addition to cord blood, maternal venous blood was obtained at delivery.

RESULTS

The median cord blood cortisol concentration in neonates of the smoking and the nonsmoking mothers was 23 and 13 microg/dL, respectively (P<0.0001). Cortisol concentrations were greater in the newborns whose mothers smoked, when compared to corresponding controls, whether they were delivered vaginally or by cesarean section. In the newborns delivered by cesarean section, there was a positive correlation between number of cigarettes smoked/day and cortisol concentrations, as well as a negative correlation between cortisol concentrations and neonatal length. There was no significant correlation between cortisol concentrations and birth weight or head circumference. Cortisol concentrations in the cord blood of neonates whose mothers were smokers and nonsmokers were by 29% and 45% lower from those measured in their mothers, respectively.

CONCLUSIONS

Although a causal relationship between maternal smoking and high cortisol concentrations in cord blood was not established, the findings are in accordance with previous reports indicating elevated stress-hormones in newborns whose mothers smoked during pregnancy.

Smoking and hormones in health and endocrine disorders

Smoking has multiple effects on hormone secretion, some of which are associated with important clinical implications. These effects are mainly mediated by the pharmacological action of nicotine and also by toxins such as thiocyanate. Smoking affects pituitary, thyroid, adrenal, testicular and ovarian function, calcium metabolism and the action of insulin. The major salient clinical effects are the increased risk and severity of Graves' hyperthyroidism and opthalmopathy, osteoporosis and reduced fertility. Smoking also contributes to the development of insulin resistance and hence type 2 diabetes mellitus. An important concern is also the effect of smoking on the foetus and young children. Passive transfer of thiocyanate can cause disturbance of thyroid size and function. Furthermore, maternal smoking causes increased catecholamine production, which may contribute to under perfusion of the foetoplacental unit.

Influence of smoking on serum and milk of mothers, and their infants' serum insulin-like growth factor-I and insulin-like growth factor binding protein-3 levels

OBJECTIVE

To investigate the serum and milk in active-smoking and nonsmoking mothers, and their infants' insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) levels.

DESIGN AND SETTING

A cohort study conducted at a tertiary medical center.

SUBJECTS

Forty-four mothers (age range: 21-34 years) and their newborns (7 days old) were enrolled in the study. Mothers were interviewed and classified according to their smoking status into one of two groups: the active-smoking mothers (n = 21) and the nonsmoking mothers (n = 23).

RESULTS

There was no difference noted in either IGF-I, IGFBP-3 or IGF-I/IGFBP-3 ratios in serum and milk of mothers, and their infants' serum samples according to maternal smoking.

CONCLUSION

This study demonstrated that maternal smoking (5-10 cigarettes/day) did not influence the maternal and infant serum levels of IGF-I and IGFBP-3 as well as the breast milk levels of these peptides.

Maternal smoking during pregnancy improves the anatomy of the hip joint in the female neonate

OBJECTIVE

Because the greater frequency of developmental dysplasia of the hip in the female could have an endocrine etiology, and because maternal smoking in pregnancy causes fetal endocrine disequilibrium, we investigated the anatomy of the hip in neonates of smoking and non-smoking mothers.

METHODS

Clinical and sonographic examination was performed on 2066 hips of 521 male and 512 female neonates. In 48 male and 53 female neonates, the mothers smoked during pregnancy.

RESULTS

The mean +/- SD alpha angle in the male neonates of the non-smoking mothers was 62.3 degrees +/- 5.1 degrees and of the smoking mothers 62.1 degrees +/- 4.9 degrees (p = 0.7). In the female neonates of the non-smoking and the smoking mothers, it was 60.7 degrees +/- 5.3 degrees and 61.9 degrees +/- 4.8 degrees, respectively (p = 0.02). The difference between the male and the female neonates of the non-smoking mothers was significant (p < 0.000001), but there was no significant difference between the female neonates of the smoking mothers and the male neonates (p = 0.5). Among the female neonates whose mothers were non-smokers, the number of those with hip type IIa or worse was significantly greater than among the female neonates whose mothers were smokers. The clinical findings were in agreement with the sonographic findings.

CONCLUSIONS

Maternal smoking during pregnancy reduces the frequency of sonographic and possibly clinically detected hip dysplasia in female but not in male neonates. Nonetheless, because smoking causes numerous adverse effects on the fetus and child, it is contraindicated during pregnancy.

Growth up to 2 years in relationship to maternal smoking during pregnancy

Smoking during pregnancy causes intrauterine growth retardation, but the subsequent growth of these children is not well understood. Two hundred four newborns of mothers who smoked during pregnancy and 204 control neonates were studied. Children were re-examined at 1 and 2 years. Newborns of mothers who smoked 1-9 cigarettes/day had similar anthropometric parameters with the controls. Significant retardation in weight, length, and head circumference was present in the newborns whose mothers smoked > or = 10 cigarettes/day. At follow-up, in children of smoking mothers the retardation of weight improved, head circumference remained stable, and length retardation increased even in children whose mothers smoked < 10 cigarettes/day.

Perinatal bone turnover in term human neonates and the influence of maternal smoking

Bone turnover in neonates appears independently of the comparably low maternal bone turnover, but there is only sparse information on the effect of the in utero environment on fetal bone turnover. Postnatally, the resuming growth velocity and alterations in mineral homeostasis affect neonatal bone turnover. This study evaluated the relationship of bone marker concentrations to maternal and fetal auxological variables as well as maternal smoking and assessed the short-term change in bone markers during the first days of life. Serum markers of bone formation [osteocalcin and bone-specific alkaline phosphatase (BALP)] and bone resorption (C-terminal telopeptide of type I collagen) were measured in cord blood and at discharge (median d 3) in 69 healthy term neonates. Concentrations of BALP were significantly lower in neonates of smokers (n = 16) compared with nonsmokers (n = 53), both at birth (p = 0.013) and at discharge (p = 0.036). Both cord osteocalcin and BALP were negatively related to maternal weight and maternal body mass index. Maternal smoking and pregnancy weight gain were the predictors of cord BALP (r2 = 0.24; p < 0.001), whereas the mode of delivery best predicted cord C-terminal telopeptide of type I collagen levels (r2 = 0.19; p < 0.001). C-terminal telopeptide of type I collagen and osteocalcin increased significantly (p < 0.001) from birth to discharge, whereas BALP levels did not change significantly during the same period. Our results suggest that maternal smoking during pregnancy and maternal obesity may have a negative impact on fetal bone formation. The significant increase of osteocalcin and C-terminal telopeptide of type I collagen may result either from an increase in bone turnover or altered renal clearance.

Cord blood leptin concentrations in relation to intrauterine growth

OBJECTIVE

Leptin, a hormone that signals the amount of energy stores to the brain, has recently been shown to play a role in the regulation of several hypothalamic pituitary axes, including the growth hormone axis. To investigate a potential association between cord blood leptin concentrations and intrauterine growth we measured leptin concentrations in the cord blood of small for gestational age (SGA), appropriate for gestational age (AGA) and large for gestational age (LGA) healthy newborns.

PATIENTS AND MEASUREMENTS

Cord blood leptin concentrations were evaluated in 25 SGA, 100 AGA, and 45 LGA, neonates.

RESULTS

Leptin was detectable in all newborns in concentrations comparable with those found in adults. Moreover, SGA newborns had lower leptin concentrations (3.70 +/- 1.81 micrograms/l) than AGA (5.65 +/- 4.98 micrograms/l) and LGA newborns (11.99 +/- 7.06 micrograms/ l)(P < 0.01). Cord blood leptin concentrations were significantly associated with ponderal index, cord blood insulin concentrations, placental weight and maternal serum leptin concentrations. Importantly, the association between cord blood leptin concentrations and intrauterine growth status persisted after adjusting for adiposity, placental weight, maternal serum leptin concentrations and cord blood insulin concentrations.

CONCLUSIONS

Cord blood leptin concentrations are independently associated with intrauterine growth. Future studies are needed to elucidate the underlying mechanism and clarify the role of leptin in regulating growth and controlling appetite in newborns.

Growth factors and intrauterine growth retardation. II. Serum growth hormone, insulin-like growth factor (IGF) I, and IGF-binding protein 3 levels in children with intrauterine growth retardation compared with normal control subjects: prospective study from birth to two years of age. Study Group of IUGR

The aim of this study was to describe serum GH, IGF-I, and IGF binding protein (BP) 3 levels at birth and during the first 2 y of life in intrauterine growth-retarded (IUGR) children and to correlate these hormonal values with auxologic parameters noted during this period to investigate their predictive value on the postnatal growth pattern. Three hundred and seventeen children were included at birth and studied for auxologic and biologic parameters at birth, 3 and 30 d, and 3, 6, 12, 18, and 24 mo of age. At birth, when analyzed according to gestational age, serum GH levels were increased (p = 0.0001) and serum IGF-I and IGFBP3 levels were decreased (p = 0.0001) in IUGR as compared with normal neonates. When two cohorts were established at birth as a function of the ponderal index (PI) (< or = or > 3rd percentile), serum IGF-I and IGFBP3 levels were found to be significantly reduced in the case of low PI. All parameters were within normal limits at 1 mo of age and remained normal thereafter. During the first 3 mo of life, a positive correlation was found between IGF-I increment and weight gain (r = 0.28, p = 0.002). None of the biologic parameters at birth were predictive either of later growth or of short stature at 2 y of age. In conclusion, low serum IGF-I and IGFBP3 levels at birth were related to fetal malnutrition and were not predictive parameters for later growth.

Increased blood pressure in neonates and infants whose mothers smoked during pregnancy

OBJECTIVE

To determine whether maternal smoking during pregnancy is associated with increased blood pressure (BP) in neonates.

STUDY DESIGN

We measured BP in the following groups: (1) 73 neonates of mothers who smoked during pregnancy, (2) 43 neonates of mothers who quit smoking early during pregnancy, (3) 83 neonates of passive smoking mothers, and (4) 170 neonates of nonsmoking parents. Three BP measurements were made at 1, 24, 48, and 72 hours of life. Some of the neonates were followed for 2 years.

RESULTS

We observed a significant positive correlation between the number of cigarettes smoked by the mothers during pregnancy and the BP of the neonates. From the first to the seventy-second hour of life the BP in the infants of the mothers who smoked 15 or more cigarettes per day was significantly higher than in the infants of the nonsmoking mothers, whereas the increase in BP was intermediate when the mothers smoked 7 to 15 cigarettes per day. The BP was similar to that of the control subjects when the mothers smoked 3 to 5 cigarettes per day, were passive smokers, or quit smoking during pregnancy. On reexamination between 4 and 9 months and at 12 months, in infants of mothers who smoked 15 or more cigarettes per day both the systolic and the diastolic BP were significantly higher than in the control subjects; at 12 months 5 of the infants of mothers who smoked cigarettes had BP greater than the 95th percentile for age and gender. At 24 months of life there was no significant difference in systolic or diastolic BP between infants of smoking and nonsmoking mothers.

CONCLUSIONS

Neonates and infants of mothers who smoked during pregnancy have an elevation of BP that is related to the number of cigarettes smoked per day. Smoking 15 or more cigarettes per day may cause BP elevation in infancy, but the BP returns to normal during the second year of life.