The effects of smoking in pregnancy on factors influencing fetal growth

Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant

The factors controlling linear growth and weight gain in the human fetus and newborn infant are poorly understood. We review here the changes in linear growth, weight gain, lean body mass, and fat mass during mid- and late gestation and the early postnatal period in the context of changes in the secretion and action of maternal, placental, fetal, and neonatal hormones, growth factors, and adipocytokines. We assess the effects of hormonal determinants on placental nutrient delivery and the impact of preterm delivery on hormone expression and postnatal growth and metabolic function. We then discuss the effects of various maternal disorders and nutritional and pharmacologic interventions on fetal and perinatal hormone and growth factor production, growth, and fat deposition and consider important unresolved questions in the field.

The Burden of Adverse Neonatal Outcome among Antenatal Substance Users in Ethiopia: A Systematic Review and Meta-Analysis

Background. Substances mainly khat, alcohol and cigarette are used during pregnancy in Ethiopia. However, to this date, there is no pooled evidence about the burden of adverse neonatal outcomes among the substance users during pregnancy in the country. Methods. Eligible primary studies were accessed from 4 international data bases (Google Scholar, Science Direct, Scopus, and PubMed). The required data were extracted from these studies and then exported to stata version 14 for analysis. Subgroup analyses were conducted for evidence of heterogeneity. Results. A total of 2298 neonates were included from 7 studies. Among these neonates, 530(23.06%) were those whose mothers used substance during pregnancy (exposed group) whereas 1768 neonates were those whose mothers didn’t use substance during pregnancy (controls group). The pooled prevalence of adverse neonatal outcome among the exposed mothers was 38.32% (95% CI: 29.48%, 47.16%; I² = 76.3%) whereas it was 16.29% (95% CI: 9.45%, 23.13%) among the controls. Adverse neonatal outcome was most burdensome among cigarette smokers 45.20% (95% CI: 37.68%, 52.73%; I² = .00%) when compared with khat chewers 34.00% (95% CI: 20.87%, 47.13%) and alcohol drinkers 38.47% (95% CI: 17.96%, 58.98%). Low birth weight 42.00% (95% CI: 18.01%, 65.99%; I² = 91.8%) was the most common adverse birth outcome. Conclusion. It was found that adverse neonatal outcomes were much more burdensome among antenatal substance users than the controls. Therefore, mothers should be enabled to quit using substance before pregnancy. Besides, strict comprehensive screening of every pregnant mother should be made at antenatal care clinics for early identification and management of antenatal substance use.

The effect of substance use during pregnancy on neonatal outcomes in Ethiopia: A systematic review and meta-analysis

BACKGROUND

Substance use during pregnancy mainly khat chewing (20%) and alcohol drinking (18.1%) are commonly practiced in Ethiopia. However, the effect of using these substances has not been studied nationally yet. Thus, this study was aimed to examine national evidence about the effect of substance use during pregnancy on birth outcome in the country, 2020.

METHODS

Primary studies were accessed through Google scholar, HINARI, SCOPUS and PubMed databases. The methodological and evidence quality of the included studies were critically appraised by the modified Newcastle-Ottawa quality assessment tool scale adapted for observational studies. From eligible studies, two authors extracted author/year, study region, study design, sample size and reported effect of antenatal substance use on birth outcome on an excel spreadsheet. During critical appraisal and data extraction, disagreements between the two authors were resolved by the involvement of a third author. The extracted data were then exported to stata version 14. Effect sizes were pooled using the fixed-effects model due to homogenous primary studies (I2 = 0.0%). Presence of publication bias was detected from asymmetry of funnel plot and statistically significant Egger's test (p = 0.000).

RESULTS

In this systematic review and meta-analysis, a total of 5,343 mother-neonate pairs were included from 15 studies. Alcohol, khat, cigarette and narghile were used during pregnancy, and significant adverse birth outcomes attributable to these substances were reported. From the pooled effect of alcohol use, drinking mothers were twice (95%CI: AOR = 2.16; 1.16, 3.17) likely to have newborns with birth defect; 9 times (95% CI: AOR = 9.39; 2.84, 15.94) more prone to own low birth weight neonates; and 1.9 times more prone to deliver preterm neonates (95% CI: AOR = 1.93; 0.52, 3.33) than the nondrinkers. Khat users were 2.4 times (95%CI: AOR = 2.4; 1.11, 5.19) more likely to have congenitally defected neonates; and 3.1 times (95%CI: AOR = 3.19; 1.01, 5.37) more risked to possess low birth weight neonates. Furthermore, antenatal cigarette smokers (95% CI: AOR = 4.36 (1.75, 6.98)) and narghile users (95% CI: AOR = 20.1; 3.94, 103) were at 4 and 20 times more likelihood of having low birth weight neonates as compared to their counterparts.

CONCLUSION

Prematurity, low birth weight and congenital malformation were the investigated adverse effects of antenatal substance use in Ethiopia. Therefore, the existing public health efforts should be encouraged to help women stop using these substances completely before pregnancy. Moreover, increasing public awareness about the potential negative impacts of substance use during pregnancy on birth outcome would be of greatest importance for comprehensive prevention of the problem.

The interaction between maternal smoking, illicit drug use and alcohol consumption associated with neonatal outcomes

BACKGROUND

The adverse effects of smoking on neonatal outcomes, such as small-for-gestational-age (SGA), has been extensively studied however, the consequences of smoking combined with alcohol and/or drug use is less clear.

METHODS

This retrospective observational study analyzed clinical and sociodemographic details of 40156 women who delivered a singleton baby between the years 2011 and 2015.

RESULTS

Compared with women who had never smoked, smokers who did not engage in alcohol or drug use had an odds ratio (OR) of delivering a baby who was SGA of 3.2 (95% CI: 3.1-3.5). Smokers who used illicit drugs in isolation or in combination with alcohol during pregnancy had higher ORs for SGA (1.4, 95% CI: 1.1-1.7, P = 0.006 and 1.8, 95% CI: 1.2-2.7, P = 0.007) compared to women who smoked but did not engage in alcohol or drug use in pregnancy. These women also delivered babies with lower mean birthweights (125 g, P < 0.001 and 181.4 g, P = 0.003) and head circumferences (0.4 cm, P < 0.001 and 0.3 cm, P = 0.048). Women who smoked and used alcohol, but not illicit drugs were not associated adverse outcomes above that of smoking in isolation.

CONCLUSION

Illicit drug use combined with maternal smoking during pregnancy increases the risk of adverse neonatal outcomes above that of smoking in isolation.

High Maternal Circulating Cotinine During Pregnancy is Associated With Persistently Shorter Stature From Birth to Five Years in an Asian Cohort

BACKGROUND

Self-reported maternal active smoking has been associated with reduced offspring birth length and shorter stature in early and late childhood.

OBJECTIVE

To use circulating cotinine as an objective biomarker to investigate the association between smoking and environmental tobacco smoke (ETS) exposure in pregnancy and longitudinal measures of offspring length/height from birth to 60 months.

METHODS

In 969 maternal-offspring dyads from the GUSTO cohort, maternal plasma cotinine at 26-28 weeks' gestation was measured by LC/MS/MS and categorized into four groups: Group 1: cotinine <0.17 ng/mL (the assay's detection limit) and no ETS exposure; Group 2: cotinine <0.17 ng/mL but self-reported ETS; Group 3: cotinine 0.17-13.99 ng/mL (ETS or light smoking); Group 4: cotinine ≥14 ng/mL (active smoking).

RESULTS

Adjusting for infant sex, gestational age at birth, ethnicity, maternal age, education, parity, BMI, and height, Group 4 offspring were shorter at birth [z-score β = -0.42 SD units (SDs) (95% CI = -0.77 to -0.06)] than Group 1 offspring. Group 4 offspring continued to be shorter at older ages, with similar effect sizes at 3 months [-0.57 SDs (-0.95 to -0.20)], 36 months [-0.53 SDs (-0.92 to -0.15)], 48 months [-0.43 SDs (-0.81 to -0.04)], and 60 months [-0.57 SDs (-0.96 to -0.17)]. Associations were particularly marked in boys. No significant differences in stature were observed in Groups 2 or 3 compared with Group 1.

CONCLUSIONS

This Asian longitudinal study associated high prenatal cotinine with persistently shorter stature in offspring from birth and into early childhood, whilst low prenatal cotinine levels and ETS exposure showed no such association.

IMPLICATIONS

Little is known about the long-term effects of prenatal tobacco exposure on offspring stature in Asia where passive smoking is common. This study has used an objective biomarker to reveal that the association of prenatal tobacco exposure with offspring length/height mainly occurs at a high maternal cotinine level of greater than 14 ng/mL in pregnancy, consistent with active smoking, but no significant associations were found with lower cotinine levels, consistent with passive smoking. Encouraging women to quit smoking prior to or during pregnancy may avert the long-term negative impact on their child's height despite appreciable prenatal ETS exposure.

The effects of amniotic fluid and foetal cord blood cotinine concentrations on pregnancy complications and the anthropometric measurements of newborns

Our objective was determining the effects of amniotic fluid (AF) and fetal cord blood (FCB) cotinine concentrations on pregnancy complications and the anthropometric measurements in the newborns whose mothers underwent amniocentesis. This study was conducted as a case-control study, in Turkey. A total of 250 pregnant women with amniocentesis indication were recruited into the study and the cotinine levels in the AF and FCB were determined. A smoking habit did not statistically affect the incidence of pregnancy complications (p>.05). The birth weights of the newborns were negatively correlated with the AF cotinine levels. The incidences of low birth weight, low Apgar scores and RDS were positively correlated with higher levels of cotinine in AF and FCB. It is important for healthcare staff to provide training and consultancy services for the health improvement of pregnant women and the prevention of smoking during pregnancy. Impact statement What is already known on this subject? The pre-pregnancy smoking habit usually continues during the pregnancy. A significant negative correlation was present between the foetal cord blood cotinine levels and the birth weight. What do the results of this study add? The anthropometric measurements of the newborns born from mothers with high AF cotinine levels were lower than newborns born from mothers with low amniotic fluid cotinine levels. Respiratory Distress syndrome is more often determined in newborns born from mothers with high AF cotinine levels. What are the implications of these findings for clinical practice and/or further research? Future studies should be performed to investigate the effects of cigarette smoking on the health problems, the growth characteristics and the neurological development of newborns and infants within the first year of life.

Active Tobacco Smoke Exposure in Utero and Concentrations of Hepcidin and Selected Iron Parameters in Newborns

The aim of this study was to assess the influence of active tobacco smoke exposure in utero on the concentration of hepcidin and selected iron markers in umbilical cord blood and to evaluate the relationships between these parameters. Newborns of smoking mothers had significantly lower concentrations of serum hepcidin (p < 0.001), iron, and ferritin (p = 0.043; p = 0.042, respectively), but higher levels of erythropoietin (EPO, p < 0.001) and soluble transferrin receptor (sTfR, p = 0.011) compared with newborns of non-smoking women. Negative correlations between cotinine and the number of cigarettes smoked per day with hepcidin serum level (r = −0.33, p = 0.033, r = −0.32, p = 0.041, respectively) and EPO (r = 0.47, p = 0.002; r = 0.46, p = 0.003, respectively) were found. Univariate analysis defined for the whole group of children revealed significant associations between the concentration of hepcidin and other iron status parameters. In the models estimated separately for smokers and non-smokers, we found relations between the level of hepcidin and erythropoietin (B = −0.23, p = 0.004; B = −0.46, p = 0.01, respectively). In the multivariate regression model, a negative association between hepcidin and EPO concentrations in the whole group of newborns (β = −0.53; p = 0.001) and in the group of smokers (β = −0.57; p = 0.011) was confirmed. The present study shows significant relations between smoking during pregnancy and hepcidin levels in children born at term. Decreased cord serum concentrations of hepcidin associated with high erythropoietin levels suggest induced fetal erythropoiesis, probably due to the hypoxic effects imposed by maternal smoking.

Changes to Fetal Steroidogenesis Caused by Maternal Smoking

Smoking during pregnancy presents health risks for both the mother and her child. In this study we followed changes in the production of steroid hormones in pregnant smokers. We focused on changes in steroidogenesis in the blood of mothers in their 37th week of pregnancy and in mixed cord blood from their newborns. The study included 88 healthy women with physiological pregnancies (17 active smokers and 71 non-smokers). We separately analyzed hormonal changes associated with smoking according to the sex of newborns. In women with male fetuses, we found higher levels of serum cortisone, dehydroepiandrosterone (DHEA), 7α-OH-DHEA, 17-OH pregnenolone, testosterone, and androstenedione in smokers at the 37th week compared to non-smokers. In women with female fetuses, we found lower serum levels of 7β-OH-DHEA and higher androstenedione in smokers at the 37th week. We found significantly higher levels of testosterone in newborn males of smokers and higher levels of 7α-OH-DHEA in female newborns of smokers. Smoking during pregnancy induces changes in the production of steroids in both the mother and her child. These changes are different for different fetal sexes, with more pronounced changes in mothers carrying male newborns as well as in the newborn males themselves.

Effect of Smoking Behavior before and during Pregnancy on Selected Birth Outcomes among Singleton Full-Term Pregnancy: A Murmansk County Birth Registry Study

The aim of our study was to assess associations between smoking behavior before and during pregnancy and selected adverse birth outcomes. This study is based on the Murmansk County Birth Registry (MCBR). Our study includes women who delivered a singleton pregnancy after 37 weeks of gestation (N = 44,486). Smoking information was self-reported and assessed at the first antenatal visit during pregnancy. We adjusted for potential confounders using logistic regression. The highest proportion of infants with low values of birth weight, birth length, head circumference, ponderal index and of the Apgar score at 5 min was observed for women who smoked both before and during pregnancy. We observed a dose-response relationship between the number of cigarettes smoked per day during pregnancy and the odds of the aforementioned adverse birth outcomes; neither were there significant differences in their occurrences among non-smokers and those who smoked before but not during pregnancy. Moreover, smoking reduction during pregnancy relative to its pre-gestation level did not influence the odds of the adverse birth outcomes. Our findings emphasize a continued need for action against tobacco smoking during pregnancy.

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.

Somatic growth in the first six months of life of infants exposed to maternal smoking in pregnancy

Background

Some studies suggest a relationship between maternal smoking during pregnancy and not only intrauterine fetal growth restriction or low birth weight, but also with changes in the postnatal growth and development. The objective of the present study was to investigate the effects of smoking during pregnancy on infants growth in the first 6 months of life compared with a control group and a group with idiopathic intrauterine growth restriction.

Methods

Longitudinal observational study using a convenience sample of newborns divided into three groups: infants of smoking mothers (tobacco), with idiopathic intrauterine growth restriction (IUGR) and a control group. The sample was selected from two hospitals in Porto Alegre, located in southern Brazil, between 2011 and 2015. Newborns were evaluated at birth, 7 and 15 days, and in the first, third, and sixth month. Anthropometric measures were weight, length and head circumference. The growth indicators used were expressed as z-scores. The analyses were performed using the generalized estimating equation method.

Results

The sample included 273 mother/newborn pairs: 86 tobacco group, 34 IUGR group, and 153 control group. In terms of weight at birth, all groups differed significantly (p < 0.001). The birth length of tobacco and control groups were similar, but the IUGR group was lower than both (p < 0.001). We found no differences in growth trajectory between tobacco and control group, but there were differences in the growth of the IUGR group when compared with the other groups. At 6 months of age, all groups had similar anthropometric measurements.

Conclusion

Intrauterine growth restriction had major impact on the growth trajectory of the infants studied, regardless of other factors, such as smoking and diet.

Prenatal exposure to tobacco smoke leads to increased mitochondrial DNA content in umbilical cord serum associated to reduced gestational age

We investigated if prenatal exposures to tobacco smoke lead to changes in mitochondrial DNA content (mtDNA) in cord serum and adversely affect newborns' health. Umbilical cord serum cotinine levels were used to determine in utero exposure to smoking. Cord serum mtDNA was measured by quantitative polymerase chain reaction analysis of the genes coding for cytochrome c oxidase1 (MT-CO1) and cytochrome c oxidase2 (MT-CO2). Log transformed levels of mtDNA coding for MT-CO1 and MT-CO2 were significantly higher among infants of active smokers with higher serum level of cotinine (p < 0.05) and inversely associated with gestational age (p = 0.08; p = 0.02). Structural equation modeling results confirmed a positive association between cotinine and MT-CO1 and2 (p < 0.01) and inverse associations with gestational age (p = 0.02) and IGF-1 (p < 0.01). We identified a dose-dependent increase in the level of MT-CO1 and MT-CO2 associated to increased cord serum cotinine and decreased gestational age.

Doppler screening and predictors of adverse outcomes in high risk pregnancies affected by tobacco

OBJECTIVE

The purpose of this study was to investigate associations between Doppler measurements and adverse outcomes in an obstetric population with high tobacco use.

METHODS

This retrospective study included patients with Doppler data (umbilical systolic/diastolic velocity ratios (S/D), uterine S/D, uterine left/right ratio index (RI)). Receiver operator characteristic curve analysis determined cut-off elevated Doppler indices. Stepwise logistic regression was used to predict adverse outcomes.

RESULTS

338 of 745 patients (45.4%) had adverse outcomes. Doppler artery indices identified significant associations with IUGR, preeclampsia, low birth weight, pre-term birth and composite adverse outcome variable. An elevated Umbilical S/D was 2.1 (95% Confidence Interval (CI): 1.5-2.9; p<0.001) times was more likely to have an adverse outcome. For left uterine artery S/D and nulliparity, the odds ratios were 1.8 (95% CI: 1.3-2.5) and 1.4 (95% CI: 1.0-1.9), respectively.

CONCLUSION

Umbilical and uterine left S/D indices and nulliparity are significant independent predictors of adverse outcomes.

Prenatal Alcohol Exposure Alters Fetal Iron Distribution and Elevates Hepatic Hepcidin in a Rat Model of Fetal Alcohol Spectrum Disorders

BACKGROUND

Prenatal alcohol exposure (PAE) causes neurodevelopmental disabilities, and gestational iron deficiency (ID) selectively worsens learning and neuroanatomical and growth impairments in PAE. It is unknown why ID worsens outcomes in alcohol-exposed offspring.

OBJECTIVE

We hypothesized that PAE alters maternal-fetal iron distribution or its regulation.

METHODS

Nulliparous, 10-wk-old, Long-Evans rats were mated and then fed iron-sufficient (100 mg Fe/kg) or iron-deficient (≤4 mg Fe/kg) diets. On gestational days 13.5-19.5, dams received either 5.0 g ethanol/kg body weight (PAE) or isocaloric maltodextrin by oral gavage. On gestational day 20.5, maternal and fetal clinical blood counts, tissue mineral and iron transport protein concentrations, and hepatic hepcidin mRNA expression were determined.

RESULTS

In fetal brain and liver (P < 0.001) and in maternal liver (P < 0.005), ID decreased iron (total and nonheme) and ferritin content by nearly 200%. PAE reduced fetal bodyweight (P < 0.001) and interacted with ID (P < 0.001) to reduce it by an additional 20%. Independent of maternal iron status, PAE increased fetal liver iron (30-60%, P < 0.001) and decreased brain iron content (total and nonheme, 15-20%, P ≤ 0.050). ID-PAE brains had lower ferritin, transferrin, and transferrin receptor content (P ≤ 0.002) than ID-maltodextrin brains. PAE reduced fetal hematocrit, hemoglobin, and red blood cell numbers (P < 0.003) independently of iron status. Unexpectedly, and also independent of iron status, PAE increased maternal and fetal hepatic hepcidin mRNA expression >300% (P < 0.001).

CONCLUSIONS

PAE altered fetal iron distribution independent of maternal iron status in rats. The elevated iron content of fetal liver suggests that PAE may have limited iron availability for fetal erythropoiesis and brain development. Altered fetal iron distribution may partly explain why maternal ID substantially worsens growth and behavioral outcomes in PAE.

Association of maternal pre-pregnancy weight, weight gain during pregnancy, and smoking with small-for-gestational-age infants in Japan

AIM

The aim of this study was to evaluate the associations of maternal pre-pregnancy body mass index (BMI), weight gain during pregnancy, and smoking, with small-for-gestational-age (SGA) births among Japanese women.

MATERIALS AND METHODS

Subjects were pregnant women who gave birth to single, term infants (37-42 weeks) at a clinic and hospital in the Nagasaki area between 2012 and 2013. To examine associations with SGA, 49 underweight (BMI<18.5 kg/m(2)) and 579 normal-weight (18.5 ≤ BMI<25.0 kg/m(2)) Japanese women with either appropriate-for-gestational-age or SGA infants were selected and analyzed.

RESULTS

The prevalence of SGA infants was 6.8%. Seven percent of women were current smokers. Prevalence of pre-pregnancy underweight and gestational weight gain less than recommendation were 20.8% and 16.7%, respectively. Multivariate logistic regression was performed to assess factors affecting SGA infants in the pregnant women. After adjusting for covariates, the amount of maternal weight gain below recommendation (odds ratio (OR), 2.72; 95% confidence interval (CI), 1.37-5.39) and maternal smoking status (OR, 2.80; 95% CI, 1.14-6.91) were significantly and independently associated with SGA births. Pre-pregnancy maternal weight status showed a borderline association (OR, 1.91; 95% CI, 0.96-3.83, p=0.067).

CONCLUSION

To prevent SGA births, education regarding the adequate nutrition and the adverse effect of maternal smoking is important for the women of reproductive age.

Maternal Smoking and Metabolic Health Biomarkers in Newborns

Background

Maternal smoking has been associated with elevated risk of type 2 diabetes among the offspring in adulthood. The mechanisms underlying this fetal “programming” effect remain unclear. The present study sought to explore whether maternal smoking affects metabolic health biomarkers in fetuses/newborns.

Methods

In a prospective singleton pregnancy cohort (n = 248), we compared metabolic health biomarkers in the newborns of smoking and non-smoking mothers. Outcomes included cord plasma insulin, proinsulin, insulin-like growth factor I (IGF-I), IGF-II, leptin and adiponectin concentrations, glucose-to-insulin ratio (an indicator of insulin sensitivity) and proinsulin-to-insulin ratio (an indicator of β-cell function).

Results

Independent of maternal (glucose tolerance, age, ethnicity, parity, education, body mass index, alcohol use) and infant (sex, gestational age, birth weight z score, mode of delivery, cord blood glucose concentration) characteristics, the newborns of smoking mothers had lower IGF-I concentrations (mean: 6.7 vs. 8.4 nmol/L, adjusted p = 0.006), and marginally higher proinsulin-to-insulin ratios (0.94 vs. 0.72, adjusted p = 0.06) than the newborns of non-smoking mothers. Cord plasma insulin, proinsulin, IGF-II, leptin and adiponectin concentrations and glucose-to-insulin ratios were similar in the newborns of smoking and non-smoking mothers.

Conclusions

Maternal smoking was associated with decreased fetal IGF-I levels, and borderline lower fetal β-cell function. Larger cohort studies are required to confirm the latter finding. The preliminary findings prompt the hypothesis that these early life metabolic changes may be involved in the impact of maternal smoking on future risk of metabolic syndrome related disorders in the offspring.

Alcohol, tobacco, cocaine, and marijuana use: relative contributions to preterm delivery and fetal growth restriction

BACKGROUND

Pregnancy substance use is linked to low birth weight. However, less is known about relative contributions of various substances and whether effects are due to decreased gestational duration, restriction of fetal growth, or both. The study goal was to use causal modeling to evaluate the individual impact of alcohol, tobacco, cocaine, and marijuana on gestational duration and fetal growth.

METHODS

Participants were 3164 urban black women recruited at entry to prenatal care and followed to delivery, with all gestational dating ultrasound supported. Pregnancy substance use was assessed via self-report (alcohol, tobacco, cocaine, and marijuana).

RESULTS

Alcohol, cigarette, and cocaine use were all individually and negatively related to gestational age at delivery. However, only alcohol, cigarette, and marijuana use predicted fetal growth, with effects for alcohol and cigarette greater and more discrepant for older women. Overall, heavy cigarette smoking had the greatest individual impact on birth weight (up to 431 g). Heavy levels of use of all 4 substances by older women decreased birth weight by 26% (806 g).

CONCLUSIONS

For perhaps the first time, reduced birth weight is apportioned both by type of substance and mechanism of effect. The use of alcohol and/or cigarettes was clearly more harmful to fetal growth than cocaine use. Findings demonstrate the need for continued emphasis on intervention efforts to address legal and illicit pregnancy substance use.

The influence of maternal smoking and exposure to residential ETS on pregnancy outcomes: a retrospective national study

In a nationwide study of Serbian births, in 2008, we estimated the influence of maternal prenatal smoking and environmental tobacco smoke (ETS) exposure on birth outcomes. Using stratified two-stage random cluster sampling, 2,721 women were interviewed in-person (response rates 98.1 %), and 2,613 singleton live births were included. Date of birth, gender, birthweight, birth height and head circumference were copied from the official hospital Birth Certificate. Six exposure categories were defined according to mother's smoking history and exposure to ETS. We calculated adjusted mean values and group differences by analysis of covariance, and adjusted odds ratios for the low birthweight (LBW < 2,500 g). Compared to the reference category (non-smoking, non-exposed to ETS) we observed birthweight reductions in infants whose mothers smoked continuously during the pregnancy and were exposed to ETS (-162.6 g) and whose mothers were not exposed to ETS (-173 g) (p = 0.000, and p = 0.003, respectively), as well as reduction in birth length (-1.01 and -1.06 cm; p = 0.003 and p = 0.000, respectively). Reduction in birthweight and birth length related to exposure categories was not linear. Adjusted OR for LBW was almost tripled for mothers who smoked over the entire pregnancy and were non-exposed to ETS (aOR 2.85; 95 % CI 1.46-5.08), and who were exposed to ETS (aOR 2.68; 95 % CI 1.15-6.25). Our results showed strong effects of smoking throughout the pregnancy on reduced birthweight, birth length and head circumference, and increased risk for LBW. We were not able to detect an effect for ETS exposure alone.

Influence of smoking status at time of surgery for herniated lumbar disk on postoperative pain and health-related quality of life

BACKGROUND

It is well established that smoking has a myriad of negative effects on varies aspects of bodily health. The aim of this study was to examine the effects of the smoking status at time of surgery on the postoperative subjective pain course and health related quality of life (HRQoL) until 1 year after surgery for lumbar disc herniation (LDH).

METHOD

This prospective cohort study included patients ≥18 and ≤90 years of age with a symptomatic and radiological verified LDH. The current smoking patient collective (smoking 1 or more cigarettes a day) was compared with the nonsmoking collective (previous smokers without cigarette consumption for >2 months and never smokers) in respect of subjective pain sensation (measured with the visual analogue scale (VAS)) and HRQoL using the short-form (SF-12) questionnaire preoperatively, before discharge, as well as after 4 weeks and 1 year postoperatively. The primary outcome measures were the 1-year SF-12 scores (MCS and PCS) categorized into responders and non-responders.

RESULTS

A total of 102 patients were enrolled in the study. Thirty-eight patients were current smokers (37.2%), whereas 43 (42.2%) and 21 (20.6%) patients were never-smokers and previous smokers, respectively. Four weeks and one year after surgery, both smokers and nonsmokers reported increase in the HRQoL as compared to preoperative values - the MCS increased more than the PCS. From a univariate and multivariate perspective, smoking status at time of surgery did not predict responder status.

CONCLUSIONS

The present study results could not confirm the hypothesis that smoking at time of surgery was associated with worse outcome after surgery for LDH.

Life course association of maternal smoking during pregnancy and offspring's height: data from the 1993 Pelotas (Brazil) birth cohort

PURPOSE

To evaluate the effect of (1) maternal smoking during pregnancy; and (2) partner smoking on offspring's height in infancy, childhood, and adolescence.

METHODS

All hospital live births from 1993 (5,249) were identified, and these infants were followed up at several ages. Height for age, expressed as z-scores using the World Health Organization growth curves, was measured at all follow-up visits. Maternal smoking during pregnancy was collected retrospectively at birth and analyzed as number of cigarettes/day smoked categorized in four categories (never smoked, <10, 10-19, and ≥ 20 cigarettes/day). Partner smoking was analyzed as a dichotomous variable (No/Yes). Unadjusted and adjusted analyses were performed by use of linear regression.

RESULTS

The prevalence of self-reported maternal smoking during pregnancy was 33.5%. In the crude analysis, the number of cigarettes/day smoked by the mother during pregnancy negatively affected offspring's height in infancy, childhood, and adolescence. After adjustment for confounders and mediators, this association remained statistically significant, although the magnitude of the regression coefficients was reduced. Paternal smoking was not associated with offspring's height in the adjusted analyses.

CONCLUSIONS

In addition to the well-known harmful effects of smoking, maternal smoking during pregnancy negatively affects offspring's height. Public health policies aimed at continuing to reduce the prevalence of maternal smoking during pregnancy must be encouraged.

Smoking in pregnancy in West Virginia: does cessation/reduction improve perinatal outcomes?

To determine if pregnant women decreasing/quitting tobacco use will have improved fetal outcomes. Retrospective analysis of pregnant smokers from 6/1/2006-12/31/2007 who received prenatal care and delivered at a tertiary medical care center in West Virginia. Variables analyzed included birth certificate data linked to intervention program survey data. Patients were divided into four study groups: <8 cigarettes/day-no reduction, <8 cigarettes/day-reduction, ≥8 cigarettes/day-no reduction, and ≥8 cigarettes/day-reduction. Analysis performed using ANOVA one-way test for continuous variables and Chi-square for categorical variables. Inclusion criteria met by 250 patients. Twelve women (4.8%) quit smoking; 150 (60%) reduced; 27 (10.8%) increased; and 61 (24.4%) had no change. Comparing the four study groups for pre-term births (<37 weeks), 25% percent occurred in ≥8 no reduction group while 10% occurred in ≥8 with reduction group (P = 0.026). The high rate of preterm birth (25%) in the non-reducing group depended on 2 factors: (1) ≥8 cigarettes/day at beginning and (2) no reduction by the end of prenatal care. Finally, there was a statistically significant difference in birth weights between the two groups: ≥8 cigarettes/day with no reduction (2,872.6 g) versus <8 cigarettes/day with reduction (3,212.4 g) (P = 0.028). Smoking reduction/cessation lowered risk of pre-term delivery (<37 weeks) twofold. Encouraging patients who smoke ≥8 cigarettes/day during pregnancy to decrease/quit prior to delivery provides significant clinical benefit by decreasing the likelihood of preterm birth. These findings support tobacco cessation efforts as a means to improve birth outcome.

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.

Somatic classification of neonates based on birth weight, length, and head circumference: quantification of the effects of maternal BMI and smoking

We defined neonates as small, appropriate, or large for gestational age (SGA, AGA, LGA) based on birth weight, length, and head circumference. We analyzed the effects on the somatic classification of maternal body mass index (BMI) (<18.5, 18.5-24.99, 25.0-29.99, ≥ 30) and smoking during pregnancy (0, 1-7, 8-14, ≥ 15 cigarettes daily). Data were from the German Perinatal Survey (1998-2000; 433,669 cases). The following refers to the classification by birth weight. In the normal maternal weight population SGA rates increased with cigarette consumption: 9.8%, 17.8%, 21.6%, and 25.4% for non-smokers, and smokers of 1-7, 8-14, and ≥ 15 cigarettes daily, respectively. In non-smoking underweight women the SGA rate was 17.4%. In underweight smokers of ≥ 15 cigarettes daily the SGA rate was 38.5% [odds ratio 5.77, 95% confidence interval 5.10-6.53, compared with normal weight non-smokers]. In the normal maternal weight population, LGA rates were 9.9%, 5.3%, 4.6%, and 3.5% for non-smokers, and smokers of 1-7, 8-14, and ≥ 15 cigarettes daily, respectively. In the obese, LGA rates were 20.9% (non-smokers) and 11.4% (≥ 15 cigarettes). Similar findings were obtained for the somatic classifications based on birth length and head circumference. Results for the various combinations of maternal BMI and smoking status in the three classification systems are described. Our findings may assist in individualized risk assessment for SGA and LGA births.

Risk factors for term small for gestational age infants in women with low prepregnancy body mass index

AIM

The purpose of our study was to investigate the association between low maternal prepregnancy body mass index (BMI) less than 18.5 kg/m(2) and the incidence of small for gestational age (SGA) infants.

MATERIAL & METHODS

This was a cross-sectional study. The women with BMI of less than 25.0 kg/m(2) who gave birth to single term infants (37-42 weeks) at clinics and hospitals in the Tokyo metropolitan area between 2003 and 2004 were analyzed for risk factors for SGA.

RESULTS

Five hundred and seventy-two women were underweight (BMI < 18.5 kg/m(2)) and 2708 (75.1%) were normal (18.5 <or= BMI < 25.0 kg/m(2)). Birthweight, analyzed by multiple regression analysis, was highly related (P < 0.05) to gestational age, maternal age, parity, prepregnancy BMI, maternal weight gain and maternal smoking status. Women with a less than 9 kg weight during pregnancy were 1.8 times (confidence interval [CI], 1.6-2.2) more likely to give birth to an SGA infant compared with women who gained 9-12 kg. Maternal smoking more than 10 cigarettes per day was associated with an increased risk of having an SGA infant (odds ratio [OR], 2.5; CI, 1.8-3.5). Women with prepregnancy BMI less than 21.0 kg/m(2) were associated with an increased risk of having an SGA infant (OR, 1.6; CI, 1.3-2.2 for BMI < 18.5 kg/m(2), and OR, 1.4; CI, 1.2-1.7 for 18.5 <or= BMI <or= 21.0 kg/m(2)).

CONCLUSION

We conclude that the detrimental effect of low prepregnancy BMI in Japanese women on birthweight and incidence of SGA infants. Our findings suggest that appropriate maternal BMI at conception followed by adequate weight gain during pregnancy may have a substantial influence on reducing the SGA infants and increasing the birthweight.

Maternal hemoglobin concentration and its association with birth weight in newborns of mothers with preeclampsia

OBJECTIVE

Maternal hemoglobin concentration is inversely related to newborn size presumably through plasma volume constriction. We sought to determine whether birth weight would show an inverse relationship to hemoglobin concentration in a group of infants whose mothers had preeclampsia, where plasma volume constriction is common.

METHODS

Electronic and paper chart review identified 142 nulliparous women with preeclampsia (excluding hemolysis, elevated liver enzymes, low platelets syndrome). Birth weight percentile was determined based on cross-sectional hybrid growth curves. Maximal third trimester maternal hemoglobin concentrations were obtained and standardised to z-scores based on gestational age matched normative data. Birth weight percentile was examined as a function of hemoglobin z-score using appropriate statistics.

RESULTS

Average gestational age at delivery was 35.9 +/- 1.9 weeks. Mean birth weight percentile for infants of preeclamptic mothers was 34 +/- 32. Mean hemoglobin z-score for mothers with preeclampsia was 0.3 +/- 1.5, significantly higher than a control population (p = 0.04). Maternal hemoglobin z-score was inversely associated with birth weight percentile (r = -0.18, p = 0.03).

CONCLUSION

Maternal hemoglobin concentrations are significantly elevated prior to delivery in women with preeclampsia. There is a statistically significant inverse correlation of maternal hemoglobin concentration to birth weight percentile.

Impaired postnatal growth of infants prenatally exposed to cigarette smoking

Most of the previous studies have shown a significant inverse relationship between smoking during pregnancy and weight, height and head circumference of infants at birth, but there is limited literature that assesses the head circumference measures of infants of smoker mothers in postnatal follow-up. The aim of this study was to assess the effects of maternal smoking and passive smoking during pregnancy on postnatal anthropometric measures of infants. Infants were divided into 3 groups: infants of smokers (n = 48), passive smokers (n = 57) and nonsmokers (n = 54), and were evaluated for their weight, height and head circumference at birth, 3 months and 6 months of age. Infants of smokers showed significant weight and head circumference deficits at birth compared to nonsmokers' infants (p < 0.05 and p < 0.001, respectively). At 6 months of age, infants of smokers continued to show significant deficits in all 3 measures compared to nonsmokers' infants (p < 0.001 for each), and infants of passive smokers showed only marginal decreases. Moreover, the weight and height growth velocities of the smokers' infants remained deficient, whereas their growth velocity of the head circumferences increased from birth up to 6 months and reached the growth velocity of the nonsmokers' infants. Infants of passive smokers showed a complete catch-up growth at 6 months. This study indicates that smoking during pregnancy results in serious deficits in infants' growth even after birth. Therefore, it is essential to inform smoker women before pregnancy the possible growth retardation of infants.

Early-life origins of schizotypal traits in adulthood

BACKGROUND

Although schizotypal traits, such as anhedonia and aberrant perceptions, may increase the risk for schizophrenia-spectrum disorders, little is known about early-life characteristics that predict more pronounced schizotypal traits.

AIMS

To examine whether birth size or several other early-life factors that have been previously linked with schizophrenia predict schizotypal traits in adulthood.

METHOD

Participants of the Northern Finland 1966 Birth Cohort Study (n = 4976) completed a questionnaire on positive and negative schizotypal traits at the age of 31 years.

RESULTS

Lower placental weight, lower birth weight and smaller head circumference at 12 months predicted elevated positive schizotypal traits in women after adjusting for several confounders (P<0.02). Moreover, higher gestational age, lower childhood family socioeconomic status, undesirability of pregnancy, winter/autumn birth, higher birth order and maternal smoking during pregnancy predicted some augmented schizotypal traits in women, some in men and some in both genders.

CONCLUSIONS

The results point to similarities in the aetiology of schitzotypal traits and schizophrenia-spectrum disorders.

Maternal smoking, biofuel smoke exposure and child height-for-age in seven developing countries

BACKGROUND

Children are at high risk of exposure to environmental tobacco smoke and biofuel smoke at home in developing countries. This study examines whether exposure to cigarette and biofuel smoke is associated with height-for-age of children (0-59 months) in seven developing countries.

METHODS

The data are from Demographic and Health Surveys conducted in Cambodia, Dominican Republic, Haiti, Jordan, Moldova, Namibia and Nepal between 2005 and 2007. The respondents were women (15-49 years) and their children in seven countries (n = 28 439), and men (15-59 years) from four countries. The outcome is a physical measurement of child height-for-age in standard deviation units.

RESULTS

Multilevel regression analysis showed that the country of residence modified the association between maternal smoking and child height-for-age. Exposure to maternal smoking was associated negatively with child height-for-age in Cambodia, Namibia and Nepal, whereas it was not in other countries. Multilevel regression analysis revealed that biofuel smoke exposure was associated with a decrease in child height-for-age [b = -0.13, 95% confidence interval (CI) = -0.19 to -0.07, P < 0.001]. No interaction was found between country of residence and biofuel smoke exposure. Multinomial logistic regression results showed that biofuel smoke exposure was associated with both stunting [odds ratio (OR) = 1.25, 95% CI = 1.08-1.44, P = 0.002) and severe stunting (OR = 1.27, 95% CI = 1.02-1.59, P = 0.04), after controlling for covariates.

CONCLUSION

The findings suggest that exposure to maternal smoking and biofuel smoke may contribute to growth deficiencies in young children. Programmes are needed to ensure smoke-free home environments for children.

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.

An epidemiologic study comparing fetal exposure to tobacco smoke in three Southeast Asian countries

The high prevalence of smoking in Southeast Asia (SEA) means pregnant women face exposure to tobacco smoke that may affect the health of their fetus. This study determined fetal exposure to tobacco smoke by meconium analysis for cotinine in 3 locations in SEA: Bulacan Province, Philippines (N=316), Bangkok, Thailand (N=106) and Singapore City (N=61). Maternal exposure to tobacco smoke was 71.1% (1.3% active; 69.8% passive) in Bulacan, 57.5% (0.9% active; 58.6% passive) in Bangkok and 54.1% (11.5% active; 42.0% passive) in Singapore. Fetal exposure to tobacco smoke (by meconium analysis) was 1.3% (Bulacan), 4.7% (Bangkok) and 13.1% (Singapore); however, a large proportion of infants who tested positive for cotinine (65%) were born to mothers who gave no history of either active or passive exposure to environmental tobacco smoke. Fetal exposure to tobacco smoke is a major health problem.

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.