Increased levels and positive correlation between erythropoietin and hemoglobin concentrations in newborn children of mothers who are smokers

Maternal Exposure to Air Pollution Is Associated with Neonatal Jaundice: A Retrospective Cohort Study

OBJECTIVE

To evaluate the association between maternal ambient pollutant exposure and neonatal jaundice in multiple pollutant species and examine sex differences.

STUDY DESIGN

Epidemiologic study: Records of 13 297 newborns (6153 male, 7144 female) born in Taichung, Taiwan were obtained from a national database. Average concentrations of prenatal air pollutants 3 months prior to birth were divided into low, middle, and high levels. Neonatal jaundice phototherapy rates between mothers who suffered varying air pollutant levels were compared. Clinical study: Three hundred seventy-six newborns (189 male, 187 female) born and received jaundice treatment with phototherapy in a hospital in Taichung, Taiwan were recruited. The correlation between prenatal exposure to air pollutants 3 months prior to birth, newborn's serum bilirubin, and serum hemoglobin were calculated.

RESULTS

Epidemiologic study: Male newborns born to mothers exposed to high carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO₂), and methane (CH₄) levels had higher phototherapy rates. In female newborns, the same was noted for CO and CH₄. Clinical study: Male newborns had a positive correlation between CO, ≤2.5 μm diameter particles, ≤10 μm diameter particles, NO, NO₂, nonmethane hydrocarbon, and CH₄ exposure 3 months prior to birth and serum bilirubin levels. Female newborns had a positive correlation for CH₄. A positive correlation between CO, ≤2.5 μm diameter particles, ≤10 μm diameter particles, NO₂, nonmethane hydrocarbon, CH₄ exposure, and serum hemoglobin levels was noted in male newborns.

CONCLUSION

Maternal exposure to air pollutants may increase neonatal jaundice treatment rates for phototherapy and higher neonatal serum total bilirubin level. Higher hemoglobin levels because of higher pollutant exposures may explain our findings. The association was more obvious in male newborns.

Iron absorption during pregnancy is underestimated when iron utilization by the placenta and fetus is ignored

BACKGROUND

Maternal iron absorption during pregnancy can be evaluated using RBC incorporation of orally administered stable iron isotope. This approach underestimates true maternal absorption of iron as it does not account for absorbed iron that is transferred to the fetus or retained within the placenta.

OBJECTIVE

Our objective was to re-evaluate maternal iron absorption after factoring in these losses and identify factors associated with iron partitioning between the maternal, neonatal, and placental compartments.

METHODS

This study utilized data from stable iron isotope studies carried out in 68 women during the third trimester of pregnancy. Iron status indicators and stable iron isotopic enrichment were measured in maternal blood, umbilical cord blood, and placental tissue when available. Factors associated with iron isotope partitioning between the maternal, neonatal, and placental compartments were identified.

RESULTS

On average, true maternal absorption of iron increased by 10% (from 19% to 21%) after accounting for absorbed iron present in the newborn (P < 0.001), and further increased by 7%, (from 39% to 42%, P < 0.001) after accounting for iron retained within the placenta. On average, 2% of recovered tracer was present in the placenta and 6% was found in the newborn. Net transfer of iron to the neonate was higher in women with lower total body iron (standardized β = -0.48, P < 0.01) and lower maternal hepcidin (standardized β = -0.66, P < 0.01). In women carrying multiple fetuses, neonatal hepcidin explained a significant amount of observed variance in net placental transfer of absorbed iron (R = 0.95, P = 0.03).

CONCLUSIONS

Maternal RBC iron incorporation of an orally ingested tracer underestimated true maternal iron absorption. The degree of underestimation was greatest in women with low body iron. Maternal hepcidin was inversely associated with maternal RBC iron utilization, whereas neonatal hepcidin explained variance in net transfer of iron to the neonatal compartment.These trials were registered at clinicaltrials.gov as NCT01019096 and NCT01582802.

Cardiac Doppler in poorly controlled gestational diabetics and its link to markers of intra-uterine hypoxia and adverse outcome

The aim of the study was to investigate foetal cardiac function using the modified myocardial performance index (Mod-MPI) in poorly controlled gestational diabetics and its link with intrauterine markers for hypoxia and to an adverse outcome. In a prospective, cross sectional study, 44 consecutive women with severe or poorly controlled gestational diabetic pregnancies in their third trimester on insulin therapy were recruited and matched with 44 women with normal pregnancies which served as the control group. Using Doppler echocardiography the foetal Mod-MPI was calculated. The foetal Mod-MPI was significantly higher in the diabetic group compared to the controls indicating significant myocardial dysfunction. The Mod-MPI served as an excellent marker of adverse outcomes. Foetal myocardial function was significantly impaired in poorly controlled gestational diabetics and there was a significant link of Mod-MPI to intrauterine markers of hypoxia, as well as to an adverse outcome. Mod-MPI has the potential to improve foetal surveillance in gestational diabetes.IMPACT STATEMENTWhat is already known on this subject? Abnormal foetal cardiac function, as reflected in the modified myocardial performance index, has been reported to be significantly increased in foetuses of poorly controlled diabetics managed on insulin.What do the results of this study add? There is a significant link between abnormal foetal cardiac function to intrauterine markers of hypoxia, as well as to an adverse outcome; and that development of myocardial dysfunction could be one of the main mechanisms, inducing foetal compromise in poorly controlled gestational diabetes.What are the implications of these findings for clinical practice and/or further research? This study explores an interesting concept of foetal pathophysiology in gestational diabetes, namely the concept of "pseudo-hypoxia" in a foetus of a gestational diabetic mother, and this intrauterine "hypoxic stress" in turn leading to myocardial dysfunction. The Mod-MPI, a clinical marker for cardiac dysfunction, can therefore be used in the clinical setting to track a deteriorating metabolic state.

Umbilical Cord Serum Ferritin Concentration is Inversely Associated with Umbilical Cord Hemoglobin in Neonates Born to Adolescents Carrying Singletons and Women Carrying Multiples

BACKGROUND

It has been proposed that the fetus prioritizes iron for hemoglobin production over delivery to tissues. However, few studies have evaluated the interrelations between hemoglobin and multiple iron status biomarkers in umbilical cord blood. A full understanding is needed of how these parameters influence each other within cord blood to fully interpret iron and hematologic status at birth.

OBJECTIVES

We evaluated the determinants of neonatal hemoglobin and assessed the interrelations between hemoglobin, serum iron status indicators, and serum iron regulatory hormones in healthy neonates.

METHODS

This was an observational study that assessed umbilical cord hemoglobin (Hb), serum ferritin (SF), erythropoietin (EPO), soluble transferrin receptor (sTfR), serum iron, hepcidin, vitamin B-12, folate, IL-6, and CRP measured in 234 neonates born to adolescents or to women carrying multiples. Correlations between these indicators were evaluated and mediation models consistent with the observed significant determinants of cord Hb concentrations were developed.

RESULTS

A highly significant inverse association was found between cord SF and Hb concentrations that was not attributable to neonatal or maternal inflammation (as measured by IL-6 and CRP). The inverse association was present in the combined cohort, as well as in the adolescent and multiples cohorts independently. Mediation analyses found that EPO and hepcidin had significant indirect effects on cord Hb, associations that are explicable by mediation through SF and sTfR.

CONCLUSION

In contrast to observations made in older infants, a highly significant inverse association between Hb and SF, as well positive associations between Hb and both sTfR and EPO, were observed in umbilical cord blood from neonates born to adolescents or women carrying multiples. These findings, combined with review of the published literature, indicate a need for analysis of the relations between multiple parameters to assess iron and hematologic status at birth. These clinical trials were registered at clinicaltrials.gov as NCT01582802 (https://clinicaltrials.gov/ct2/show/NCT01582802) and NCT01019902 (https://clinicaltrials.gov/ct2/show/NCT01019902).

Gestational hypoxia disrupts the neonatal leptin surge and programs hyperphagia and obesity in male offspring in the Sprague-Dawley rat

The effect of gestational hypoxia on the neonatal leptin surge, development of hypothalamic arcuate nuclei (ARH) projections and appetite that could contribute to the programming of offspring obesity is lacking. We examined the effect of 12% O₂ from gestational days 15–19 in the Sprague-Dawley rat on post-weaning appetite, fat deposition by MRI, adipose tissue cytokine expression, the neonatal leptin surge, ARH response to exogenous leptin, and αMSH projections to the paraventricular nucleus (PVN) in response to a high fat (HFD) or control diet (CD) in male offspring. Normoxia (NMX) and Hypoxia (HPX) offspring exhibited increased food intake when fed a HFD from 5–8 weeks post-birth; HPX offspring on the CD had increased food intake from weeks 5–7 vs. NMX offspring on a CD. HPX offspring on a HFD remained hyperphagic through 23 weeks. Body weight were the same between offspring from HPX vs. NMX dams from 4–12 weeks of age fed a CD or HFD. By 14–23 weeks of age, HPX offspring fed the CD or HFD as well as male NMX offspring fed the HFD were heavier vs. NMX offspring fed the CD. HPX offspring fed a CD exhibited increased abdominal adiposity (MRI) that was amplified by a HFD. HPX offspring fed a HFD exhibited the highest abdominal fat cytokine expression. HPX male offspring had higher plasma leptin from postnatal day (PN) 6 through 14 vs. NMX pups. HPX offspring exhibited increased basal c-Fos labeled cells in the ARH vs. NMX pups on PN16. Leptin increased c-Fos staining in the ARH in NMX but not HPX offspring at PN16. HPX offspring had fewer αMSH fibers in the PVN vs. NMX offspring on PN16. In conclusion, gestational hypoxia impacts the developing ARH resulting in hyperphagia contributing to adult obesity on a control diet and exacerbated by a HFD.

Expression of StAR and Key Genes Regulating Cortisol Biosynthesis in Near Term Ovine Fetal Adrenocortical Cells: Effects of Long-Term Hypoxia

We previously demonstrated decreased expression of key genes regulating cortisol biosynthesis in long-term hypoxic (LTH) sheep fetal adrenals compared to controls. We also showed that inhibition of the extracellular signal-regulated kinases (ERKs) with the mitogen-activated protein kinase (MEK)/ERK inhibitor UO126 limited adrenocorticotropic (ACTH)-induced cortisol production in ovine fetal adrenocortical cells (FACs), suggesting a role for ERKs in cortisol synthesis. This study was designed to determine whether the previously observed decrease in LTH cytochrome P45011A1/cytochrome P450c17 (CYP11A1/CYP17) in adrenal glands was maintained in vitro, and whether ACTH alone with or without UO126 treatment had altered the expression of CYP11A1, CYP17, and steroidogenic acute regulatory protein (StAR) in control versus LTH FACs. Ewes were maintained at high altitude (3820 m) from ∼40 days of gestation (dG). At 138 to 141 dG, fetal adrenal glands were collected from LTH (n = 5) and age-matched normoxic controls (n = 6). Fetal adrenocortical cells were challenged with ACTH (10^-8 M) with or without UO126 (10 µM) for 18 hours. Media samples were collected for cortisol analysis and messenger RNA (mRNA) for CYP11A1, CYP17, and StAR was quantified by quantitative real-time polymerase chain reaction. Cortisol was higher in the LTH versus control ( P < .05). StAR mRNA was decreased in LTH versus control ( P < .05). U0126 alone had no effect on mRNA in either group. UO126 prevented the increase in CYP11A1 and CYP17 in control FACs. Basal CYP11A1 and CYP17 were not different in LTH versus control. ACTH increased CYP11A1 and CYP17 only in control FACs ( P < .05). U1026 attenuated the ACTH response indicative of a role for ERK in CYP11A1 and CYP17 expression. ACTH may require additional factors in FACs to fully regulate StAR expression.

Prenatal tobacco smoke exposure, risk of schizophrenia, and severity of positive/negative symptoms

Prenatal exposure to cigarette smoke causes chronic fetal hypoxia, dysregulation of endocrine equilibrium, and disruption of fetal neurodevelopment associated with brain malfunction, all of which potentially could induce vulnerability to schizophrenia. A total of 212 schizophrenia patients aged 14-30years, and 212 matched controls were studied. Prenatal tobacco smoke exposure of the schizophrenia patients was compared to that of the normal controls by applying logistic regression analysis and controlling for several confounding factors. The outcomes of interest were comparison of the frequency of maternal and paternal smoking between patients and controls, as well as the severity of positive and negative symptoms between the offspring of smoking and nonsmoking parents. Among the mothers of schizophrenia patients and controls, 92 (43.4%) and 46 (21.7%) smoked, respectively. Maternal smoking during pregnancy had a significant unique contribution on increasing the risk for development of schizophrenia (p=0.001), and a greater severity of negative symptoms (p=0.023). Paternal smoking did not have a significant effect on the risk of schizophrenia, or severity of negative symptoms. The findings suggest that maternal smoking during pregnancy puts offspring at an increased risk for later schizophrenia, with increased severity of negative symptoms. Given the wide practice of smoking during pregnancy, fetal exposure to tobacco smoke could be a major preventable neurodevelopmental factor that increases vulnerability to schizophrenia.

Extracellular signal-regulated kinases (ERK1/2) signaling pathway plays a role in cortisol secretion in the long-term hypoxic ovine fetal adrenal near term

This study assessed the role of the extracellular signal-regulated kinase (ERK) signaling pathway on the previously observed enhanced cortisol secretion in response to adrenocorticotropic hormone (ACTH) treatment in fetal adrenocortical cells (FACs) from long-term hypoxic (LTH) ovine fetuses. Ewes were maintained at high altitude (3,820 m) from ~40 to 138-141 days gestation when FACs were collected and challenged with either ACTH (10 nM) or 8-bromoadenosine 3',5'-cyclic monophosphate (8-bromo-cAMP, 10 mM) in the presence or absence of the mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MEK)/ERK inhibitor UO126 (10 μM). FACs from age-matched normoxic fetuses served as controls. Media and FACs were collected at selected time intervals after ACTH or 8-bromo-cAMP stimulation for cortisol measurement and Western analysis of ERK1/2 and phospho-ERK1 and -2 (pERK1/2). After ACTH or 8-bromo-cAMP treatment, cortisol production was greater in the LTH group compared with control (P < 0.05). UO126 reduced ACTH and 8-bromo-cAMP-mediated cortisol output in both groups (P < 0.01 vs. ACTH or 8-bromo-cAMP alone). Under basal conditions, ERK1/2 and pERK1/2 were not different between LTH and normoxic fetuses. In response to ACTH or 8-bromo-cAMP treatment, ERK1/2 were not different between groups; however, pERK1/2 were elevated in the LTH FACs compared with normoxic control FACs. ERK1/2 phosphorylation declined following ACTH treatment in the control group, but UO126 had no effect on ERK1/2 compared with untreated levels. Both ACTH and 8-bromo-cAMP treatment resulted in a decline of protein levels. UO126 pretreatment virtually eliminated pERK1/2 expression. We conclude that basal ERK signaling in FACs is necessary for normal cortisol production and sustained pERK in LTH adrenals enhances cortisol production.

Umbilical cord serum erythropoietin levels and maternal smoking in pregnancy

Objective. To evaluate the effect of maternal smoking during pregnancy on levels of umbilical cord erythropoietin. Methods. Erythropoietin levels were measured in umbilical cord sera of 60 newborns who were delivered vaginally at term. There were 20 (33%) smoking and 40 (67%) nonsmoking mothers. Results. Mean cord serum erythropoietin levels were significantly lower in the nonsmokers (nonsmokers, 24 ± 9 IU/L; smokers, 61 ± 46 IU/L; P < .001). There was a significant positive correlation between the number of cigarettes smoked per day and cord serum erythropoietin levels (r, 0.58; P ≤ .05). Conclusions. Smoking during pregnancy is associated with increased levels of umbilical cord erythropoietin at birth. This may indicate a risk of fetal hypoxia and growth restriction. Education and encouragement of cessation of smoking during pregnancy are important to avoid associated fetal and maternal morbidity and mortality.

Maternal resveratrol treatment during pregnancy improves adverse fetal outcomes in a rat model of severe hypoxia

Prenatal hypoxia is a common complication in pregnancy. We sought to determine whether resveratrol, a phytoalexin shown to improve health in several species, improves fetal outcomes associated with prenatal hypoxia in rats. Supplementation of maternal diets with resveratrol (4 g/kg diet) from gestational day (GD) 7 to GD21 almost completely reversed fetal demise in hypoxic (8.5% oxygen) pregnancies. We also show that resveratrol crosses the placenta, and may affect the fetus directly.

Iron-fortified vs low-iron infant formula: developmental outcome at 10 years

OBJECTIVE

To assess long-term developmental outcome in children who received iron-fortified or low-iron formula.

DESIGN

Follow-up at 10 years of a randomized controlled trial (1991-1994) of 2 levels of formula iron. Examiners were masked to group assignment.

SETTING

Urban areas around Santiago, Chile.

PARTICIPANTS

The original study enrolled healthy, full-term infants in community clinics; 835 completed the trial. At 10 years, 473 were assessed (56.6%).

INTERVENTION

Iron-fortified (mean, 12.7 mg/L) or low-iron (mean, 2.3 mg/L) formula from 6 to 12 months.

MAIN OUTCOME MEASURES

We measured IQ, spatial memory, arithmetic achievement, visual-motor integration, visual perception, and motor functioning. We used covaried regression to compare iron-fortified and low-iron groups and considered hemoglobin level before randomization and sensitivity analyses to identify 6-month hemoglobin levels at which groups diverged in outcome.

RESULTS

Compared with the low-iron group, the iron-fortified group scored lower on every 10-year outcome (significant for spatial memory and visual-motor integration; suggestive for IQ, arithmetic achievement, visual perception, and motor coordination; 1.4-4.6 points lower; effect sizes, 0.13-0.21). Children with high 6-month hemoglobin levels (> 12.8 g/dL [to convert to grams per liter, multiply by 10]) showed poorer outcome on these measures if they received iron-fortified formula (10.7-19.3 points lower; large effect sizes, 0.85-1.36); those with low hemoglobin levels (< 10.5 g/dL) showed better outcome (2.6-4.5 points higher; small but significant effects, 0.22-0.36). High hemoglobin levels represented 5.5% of the sample (n = 26) and low hemoglobin levels represented 18.4% (n = 87).

CONCLUSION

Long-term development may be adversely affected in infants with high hemoglobin levels who receive 12.7 mg/L of iron-fortified formula. Optimal amounts of iron in infant formula warrant further study.

Prenatal tobacco exposure influences cerebral oxygenation in preterm infants

AIM

Our aim was to determine the influence of prenatal tobacco exposure on regional cerebral tissue oxygen saturation (r(c)SO(2)) and fractional tissue oxygen extraction (FTOE) in preterm infants. We hypothesized that as a result of vasoconstriction caused by prenatal tobacco exposure r(c)SO(2) would be lower and FTOE would be higher during the first days after birth in infants exposed to tobacco during pregnancy.

METHODS

Sixty preterms were included in this prospective, observational cohort study (median gestational age 29.9 weeks, range 26.0-31.8, median birth weight 1248 g, range 615-2250). Fourteen infants had been exposed to tobacco during pregnancy. All mothers smoked more than five cigarettes a day till delivery. We measured r(c)SO(2) and transcutaneous arterial oxygen saturation (tcSaO(2)) in all infants on days 1-5, 8, and 15. FTOE was calculated: FTOE=(tcSaO(2)-r(c)SO(2))/tcSaO(2).

RESULTS

In preterm infants exposed to tobacco during pregnancy, r(c)SO(2) was lower during days 1, 2, and 8 after birth, median 73% versus 81%, 73% versus 80% and 71% versus 78% respectively. FTOE was higher during days 1 and 8 after birth, median 0.24 versus 0.15 and 0.26 versus 0.19 respectively. On the second day, FTOE tended to be higher, 0.18 versus 0.14.

CONCLUSIONS

During the first two days and day 8 after birth cerebral oxygen saturation is lower and oxygen extraction higher in preterm infants following prenatal tobacco exposure. Our data suggest that prenatal tobacco exposure may have an effect on cerebral oxygenation of the infant.

Global screening of human cord blood proteomes for biomarkers of toxic exposure and effect

BACKGROUND

Exposures of pregnant women to natural and manmade chemicals can lead to negative health effects in the baby, ranging from low birth weight to developmental defects. In some cases, diseases were postulated to have their basis in toxic exposure in utero or in early childhood. Therefore, an understanding of fetal responses to environmental exposures is essential. To that end, cord blood is a readily accessible biofluid whose proteomic makeup remains mostly unexplored when compared with that of adults.

OBJECTIVES

Our goal was an initial global assessment of the fetal serum proteome and for the identification of protein biomarkers indicative of toxic in utero exposures related to maternal cigarette smoking.

METHODS

Drawing from a repository of 300 samples, we selected umbilical cord blood sera from 12 babies born to six smokers and six nonsmokers and analyzed both sample pools by tandem mass spectrometry in conjunction with isobaric tags (iTRAQ) for protein quantification.

RESULTS

We identified 203 proteins, 17 of which were differentially expressed between the cigarette smoke-exposed and control populations. Most of the identified candidate biomarkers were biologically plausible, thereby underscoring the feasibility of screening neonates with global proteomic techniques for biomarkers of exposure and early biological effects triggered by in utero chemical exposures.

CONCLUSIONS

This validation study provides an initial view of the proteome of human cord blood sera; it demonstrates the feasibility of identifying therein by use of proteomics, biomarkers of environmental, toxic exposures.

Increased fetal plasma and amniotic fluid erythropoietin concentrations: markers of intrauterine hypoxia

Tissue hypoxia is the major stimulus of erythropoietin (EPO) synthesis in fetuses and adults. Since EPO does not cross the placenta and is not stored, fetal plasma and amniotic fluid levels indicate EPO synthesis and elimination. Acutely, the rate and magnitude of the increase in plasma EPO levels correlate with the intensity of hypoxia. Amniotic fluid EPO levels correlate with cord plasma levels in normal and abnormal pregnancies, with fetal plasma EPO levels in humans averaging 2.6 times higher than the corresponding amniotic fluid EPO levels. Recent experimental and clinical studies demonstrate that EPO has neuroprotective effects related to its anti-apoptotic and vascular growth-promoting properties. Although under basal conditions the fetal kidneys are the main site of EPO production, during hypoxia recent experimental data indicate an important role of the placenta. Amniotic fluid EPO levels have been shown to increase exponentially during fetal hypoxia in preeclamptic, diabetic and Rh-immunized pregnancies, to correlate inversely with cord blood pH, pO(2) and base excess and to predict neonatal morbidities and NICU admission. As an indicator of chronic intrauterine hypoxia, fetal EPO measurements have increased our knowledge about the pathogenesis and importance of intrauterine growth restriction, macrosomia, diabetic pregnancy, prolonged pregnancy, meconium staining, fetal hemorrhage, fetal anemia, maternal smoking and alcohol consumption, abnormal fetal heart rate and abnormal Doppler flow patterns. While the clinical utility of fetal amniotic fluid and plasma EPO measurements in the management of high-risk pregnancies and their offspring is promising, adequately powered clinical trials are urgently needed.

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.

The effects of smoking in pregnancy on factors influencing fetal growth

AIM

To evaluate the influence of maternal smoking during pregnancy on factors influencing fetal growth.

METHODS

Thirty newborns of smoking mothers were prospectively compared with 60 newborns of non-smoking mothers. Pre-albumin, albumin, triglycerides, glucose, insulin, insulin-like growth factor I, IGF binding protein 3, pH, lactic acid, erythropoietin and hemoglobin concentrations were measured in umbilical cord blood.

RESULTS

Infants of smoking mothers had a significantly lower birth weight (3418 +/- 533 vs. 3863 +/- 503 g; p < 0.001), length (50.5 +/- 2,6 vs. 52.3 +/- 1.9 cm; p < 0.001) and head circumference (34.6 +/- 1.8 vs. 35.8 +/- 1.1 cm; p < 0.001) than controls. They also had significantly lower insulin (3.2 (2.0-4.9) vs. 5.8 (4.6-7.1) mU/L; p = 0.008), insulin-like growth factor I (54.4 +/- 32.5 vs. 93.8 +/- 54.5 microg/L; p = 0.001) and IGF binding protein 3 (1664 +/- 432 vs. 1943 +/- 421 microg/L; p = 0.01) concentrations, than controls. Infants of smoking mothers also had significantly higher hemoglobin (167 +/- 14 vs. 157 +/- 13 g/L; p = 0.002) and erythropoietin (42.3 (25.1-72.4) vs. 26.3 (21.9-30.9) U/L; p = 0.03) than controls, but not pH or lactate concentrations. There was no significant difference in pre-albumin, albumin, triglycerides and glucose concentrations.

CONCLUSIONS

Smoking during pregnancy causes symmetrical fetal growth impairment, possibly due to decreased oxygen transport to the fetus and decreased concentrations of fetal insulin, insulin-like growth factor I and IGF binding protein 3.

[Nicotine replacement therapies during pregnancy: what do we know about the balance between benefits and risks?]

Maternal smoking during pregnancy induces obstetrical and fetal complications but also has an impact on newborns, infants, children and adults. Nicotine replacement therapies are authorized during pregnancy in France, the purpose being to reduce fetal exposure to toxic compounds in tobacco smoke. However, it is not proven that nicotine replacement therapy is harmless to the fetus and to date, no study has demonstrated any beneficial effect in terms of abstinence. It is suggested that benefit and risks of nicotine replacement therapies during pregnancy should be evaluated.

Growth patterns of the heart and kidney suggest inter-organ collaboration in facultative fetal growth

Maternal smoking during pregnancy has been associated with a number of negative sequelae among offspring, including elevated postnatal blood pressure. While animal studies have described organ level alterations with smoke exposure, human data have been more limited. Thirty-four healthy maternal/fetal pairs (24 nonsmokers, 10 smokers) participated in a longitudinal growth study from the thirteenth week of pregnancy to document fetal kidney and heart growth trajectories and morphology. Curve fitting followed by a mixed model for repeated measures identified significantly different growth patterns in kidney width, thickness, length, and volume growth with exposure: the smoke-exposed fetal kidney was wide and thick compared to the unexposed kidney during the second and early third trimester, declining to proportionately thin kidneys for length and width subsequently. Cardiac growth in width and volume followed a reverse pattern: a surge in cardiac volume occurred after 30 weeks with acceleration in cardiac width, resulting in a heart that was wide for length and for fetal weight. Smoke exposure altered fetal growth in size and timing of the heart and kidneys during midgestation, with changes in organ morphology suggesting compensatory growth. These are the first data providing anatomical evidence of altered renal/cardiac volume relationships that may provide a mechanism to previously reported sequelae of in utero smoke exposure. They suggest that cell-level adaptive responses to hypoxia and/or chemical insults are operative and illustrate the importance of longitudinal ultrasound to directly assess the organ-level growth response of the human fetus to a prenatal stress, in lieu of relying on birth outcome measures.

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.

Prenatal smoke exposure alters growth in limb proportions and head shape in the midgestation human fetus

The objective of this study was to examine the effects of smoke exposure on the growth patterns of the head, limbs, and torso of the midgestation human fetus. Four hundred maternal/fetal pairs contributed to this analysis: 366 individuals were assessed cross-sectionally (87 smokers and 279 nonsmokers) at approximately 20 and 32 weeks, and 34 individuals were followed longitudinally at 23, 27, and 32 weeks (10 smokers, 24 nonsmokers). Ten body parameters were measured by fetal ultrasound. In both samples, controlling for day of measurement, smoke exposure was significantly associated with early growth acceleration in head and abdominal diameters at 20-27 weeks (P < 0.05). This was followed by altered head shape (a significantly smaller biparietal to occipital frontal diameter ratio at 32 weeks, P < 0.01), and a proximal/distal growth gradient as proportionately long arms (P < 0.05 at 27 and 32 weeks) and short legs were apparent by 32 weeks, with a significant reduction in the tibia/femur ratio (P = 0.04). These fetal body growth patterns, expressed in terms of size and proportionality, are consistent with the presence of chronic hypoxia associated with maternal smoking. The growth pattern differences identify that prenatal smoking is not merely an insult resulting in consistent size and growth rate reduction across developmental ages. Instead, smoke exposure alters the growth rate of individual body segments at variable developmental stages as the fetus experiences selective growth restriction and augmentation. We hypothesize that the growth patterns observed here reflect the unique pattern of fetal blood flow favoring upper body oxygen distribution and extraction, together with genetically based adaptive strategies that permit the fetus to adjust the timing and magnitude of its growth to local environmental resources. It is possible that dolichocephaly is a previously unappreciated marker of fetal hypoxia. Reduced tibial growth may be a good marker for shortfall and a useful proxy for the adequacy of circulating resources more generally.

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.

Estimation of cord blood erythropoietin in pre-eclampsia and eclampsia

OBJECTIVE

The estimation of cord blood erythropoietin in subjects with pre-eclampsia and eclampsia.

METHOD

Erythropoietin was measured, using ELISA, in the cord blood of infants born to 83 mothers with pre-eclampsia, and 7 with eclampsia. Another 90 subjects with no evidence of pre-eclampsia or eclampsia were taken as control subjects. Maternal parity, gestational age, blood pressures, 24-h urine protein and Apgar scores of the infants delivered were also noted.

RESULT

Cord blood erythropoietin levels were statistically significantly higher (P<0.001) in infants born to mothers with pre-eclampsia and eclampsia. There was a significant positive correlation (P<0.01) between cord blood erythropoietin levels and maternal blood pressure (systolic and diastolic) and albuminuria. A negative correlation (P<0.01) was observed with the birth weights of infants.

CONCLUSION

Pre-eclampsia and eclampsia are associated with higher levels of cord blood erythropoietin.

Effect of passive smoking in pregnancy on neonatal nucleated red blood cells

OBJECTIVE

We evaluated whether the absolute nucleated red blood cell (RBC) count is elevated in term, appropriate for gestational age (AGA) infants born to women exposed to passive smoking in pregnancy.

PATIENTS AND METHODS

We compared absolute nucleated RBC counts taken during the first 12 hours of life in 2 groups of term, vaginally delivered infants, 1 group born to mothers who were routinely exposed to tobacco smoke during pregnancy (n = 55) either at home or at the workplace, and the other to mothers who were not routinely exposed to any tobacco smoke (n = 31). We excluded infants of women with conditions known to elevate nucleated RBC counts.

RESULTS

There were no differences between groups in birth weight, maternal age, gravidity, parity, maternal analgesia during labor, 1- and 5-minute Apgar scores. Gestational age was minimally higher in the control group (39.6 +/- 1.1 vs 39.2 +/-.8 weeks). The median absolute nucleated RBC count in the passive smoking group was 357 x 10(6)/L (range: 0-5091 x 10(6)/L) versus 237 x 10(6)/L (range: 0-1733 x 10(6)/L) in nonsmoking controls. Stepwise regression analysis that included Apgar scores, gestational age, and the passive smoking status (yes/no) as independent variables showed significant correlation of absolute nucleated RBC count only with the passive smoking status.

CONCLUSION

At birth, term AGA infants born to mothers exposed to passive smoking have increased circulating absolute nucleated RBC counts compared with those of controls. We speculate that passive smoking in pregnancy should be avoided, because it may have subtle negative effects on fetal oxygenation.

Erythropoietin in obstetrics

Our objective was to discuss the role of erythropoietin in fetal erythropoiesis and to review its clinical uses in perinatal medicine. All relevant articles compiled through a MEDLINE search (years 1986-1997) were reviewed. Erythropoietin is essential for fetal erythropoiesis and is produced in response to hypoxia and anemia. Cord blood erythropoietin is purely fetal and reflects tissue oxygenation. It has been found to be increased in many complicated pregnancies with underlying fetal hypoxia. Erythropoietin could be used as a marker of fetal hypoxia because its concentration rises rapidly by increased production in response to hypoxia. Its measurement might enable more accurate timing of hypoxic injury. In addition, erythropoietin levels have been well correlated with perinatal brain damage and may facilitate treatment of high risk neonates. Erythropoietin has also been used successfully in anemia of prematurity, decreasing the transfusion requirement. However, studies are still needed to determine the optimal doses of erythropoietin and iron supplementations required for maximizing the red blood cell response. Erythropoietin has been examined as potential maternal therapy in various disorders during pregnancy. These include end-stage renal disease, severe antepartum iron deficiency anemia, and postpartum anemia. Erythropoietin has been found to be effective and well tolerated in these conditions. An additional promising use lies in the optimization of maternal red blood cell mass to allow autologous blood donation. This may be critical in cases where a large amount of bleeding might be anticipated, as with placenta previa. This would also minimize the donor transfusion-related hazards. Erythropoietin with its wide clinical applications could improve maternal and neonatal outcome.

Erythropoietin levels can be used to determine tissue oxygenation in critically ill patients

Critically ill patients often require pharmacological support to maintain blood pressure and cardiac output, and mechanical ventilation to ensure adequate oxygenation. Current methods of measurement of oxygen delivery do not necessarily reflect tissue oxygenation. Levels of circulating erythropoietin reliably reflect the adequacy of renal oxygen supply under physiological and many pathological conditions. It is proposed that the measurement of circulating erythropoietin can be used as a measure of tissue oxygenation in critically ill patients.

Fetal and maternal adaptations to chronic hypoxia: prevention of premature labor in response to chronic stress

Both mother and fetus have the remarkable ability to adapt to conditions of chronic hypoxia during the course of gestation. One of these adaptations appears to be mechanisms that prevent premature delivery despite the chronic stress of hypoxia. Our studies in the chronically hypoxic sheep revealed that the fetal adrenal is less responsive to ACTH stimulation. This in turn may prevent a premature rise in cortisol that would normally trigger labor and delivery. In the rat, the myometrium is affected with a decrease in contractile sensitivity to oxytocin following chronic hypoxia. This response is mediated by a significant reduction in myometrial oxytocin receptors. Our preliminary studies have also suggested that this blunting of myometrial responsiveness also occurs in the chronically hypoxic sheep. Taken together, these data indicate an adaptive response by both mother and fetus to prevent preterm delivery in the face of a chronic stress.

Umbilical cord plasma erythropoietin levels in pregnancies complicated by maternal smoking

OBJECTIVE

Our goal was to determine whether maternal smoking was associated with elevated umbilical cord erythropoietin, a marker for chronic hypoxia.

STUDY DESIGN

Plasma erythropoietin levels were measured in umbilical cord plasma of 222 newborns. There were 48 mothers who smoked and 174 nonsmokers.

RESULTS

When all pregnancies were included, mean cord plasma erythropoietin levels were significantly higher in the smokers (78.0 +/- 15.3 mIU/ml) compared with the nonsmoking group (35.2 +/- 4.0 mIU/ml; p < 0.005). Regression analysis showed a significant positive correlation between the number of cigarettes smoked per day and cord plasma erythropoietin levels (r = 0.26, p < 0.0001). Smoking was associated with a significantly elevated risk (relative risk = 2.6, 95% confidence interval 1.7 to 10.9, p < 0.005) of fetal growth restriction. When pregnancies with fetal growth restriction were excluded from the analysis, the difference between the two groups remained significant (smokers 81.3 +/- 18.6, n = 38; nonsmokers 24.3 +/- 1.4, n = 164; p < 0.03).

CONCLUSIONS

These results illustrate that smoking during pregnancy is associated with fetal growth restriction and significantly elevated umbilical cord erythropoietin levels.

Interactions between maternal smoking and other prenatal risk factors for sudden infant death syndrome (SIDS)

In numerous investigations, maternal smoking increases the risk of sudden infant death syndrome (SIDS). In the present study we investigated whether prenatal risk factors for SIDS modify the effect of maternal smoking on SIDS mortality. We analysed data from a population-based cohort study (222 cases, 260,604 infants at risk) within the Westphalian Perinatal Inquiry in Germany between 1990 and 1994. In the stratified analysis, smoking was classified into non-smoking, moderate (1-10 cigarettes/d) and heavy smoking (> 10 cigarettes/d). Multiplicative interactions between smoking and other prenatal risk factors were assessed in a logistic regression model. The relative risk (RR) for maternal smoking was 2.4 (95% confidence interval 1.7-5.4) for moderate and 7.2 (5.3, 9.7) for heavy smokers. Previous established risk factors for SIDS, such as preterm birth, low birthweight, and number of prenatal visits did not increase the risk of SIDS among non-smokers, but became important risk factors among smokers. In preterm infants (< 37 weeks) of heavy smokers, the RR was 19.6 (10.4, 36.8) compared to term infants of non-smokers. Low birthweight infants (< 2500 g) of heavy smokers had a RR of 16.3 (8.4, 31.2) compared to normal weighted infants of non-smokers. Adjustment for occupational status did not change the crude estimates. The RR of < 6 prenatal visits in the heavy smoking subgroup was 14.8 (7.2, 29.6) compared to > 9 prenatal visits in the non-smoking strata. Heavy smoking potentiates other prenatal risk factors for SIDS suggesting an increased susceptibility towards the adverse effects of tobacco smoke in utero. In infants born to non-smoking mothers, prenatal risk factors are absent and postnatal factors may be of major importance.

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.