Influence on fetal growth of exposure to tobacco smoke during pregnancy

Timing of Maternal Smoking Cessation and Newborn Weight, Height, and Head Circumference

OBJECTIVE

To examine the relationship between timing of smoking cessation during pregnancy and anthropometric indices of newborns.

METHODS

Mothers and neonates enrolled in the JECS (Japan Environment and Children's Study), a nationwide birth cohort study, were examined. Patients with full-term neonates were included in the analysis, and 73,025 mother-neonate pairs with complete data were identified. The mothers were classified into six groups according to smoking status during pregnancy (nonsmokers [Q1, n=44,198]; ex-smokers who quit before pregnancy [Q2, n=16,461]; ex-smokers who quit in the first trimester [Q3, n=8,948]; ex-smokers who quit in the second trimester [Q4, n=498]; ex-smokers who quit in the third trimester [Q5, n=651]; and smokers who smoked throughout pregnancy [Q6, n=2,269)]). Data on smoking were based on questionnaires administered in the first, second, or third trimester and 1 month after delivery. The primary outcomes were birth weight, height, and head circumference.

RESULTS

Compared with nonsmokers (Q1), no adverse outcomes were observed for ex-smokers who quit before pregnancy (Q2). The mean adjusted weights of male and female neonates were 135 g and 125 g lower, respectively, in Q6 participants than in Q1 participants. Comparing Q1 and Q6 participants, height was 0.6 cm and 0.7 cm smaller for male and female neonates, respectively. Head circumference in neonates of Q6 participants was 0.3 cm and 0.3 cm smaller for male and female neonates, respectively, than that in Q1 participants. Across all three measures, smoking cessation in the first and second trimester reduced the differential in outcomes between nonsmokers and individuals who smoked throughout pregnancy.

CONCLUSION

Smoking during pregnancy is associated with reduced newborn birth weight, height, and head circumference. Earlier smoking cessation during pregnancy reduces the adverse effects of smoking on fetal growth.

Effects of active and/or passive smoking during pregnancy and the postpartum period

INTRODUCTION

Tobacco smoking may cause adverse effects during pregnancy and postpartum. The aim of this study was to evaluate several repercussions of active and/or passive smoking by the mother at home, during pregnancy, at delivery, as well as for the newborn baby and breastfeeding, including the effect of quitting smoking in the first trimester of pregnancy.

METHODS

A prospective longitudinal study was carried out with a sample of 800 pregnant women. Four evaluations were made: first and third trimester of pregnancy, and 2 and 6/8 months postpartum. Sociodemographic, obstetric, health and tobacco consumption details were collected, with biochemical tests being performed to confirm the self-reported abstinence.

RESULTS

Being an active and passive smoker predicted suffering complications in pregnancy (OR 2.50; 95% CI; 1.42-4.35) and delivery (OR 3.10; 95% CI; 1.75-5.51), and also tended not to breastfeed (OR 2.44; 95% CI; 1.35-4.42). Being an active smoker predicted complications at childbirth (OR 5.58; 95% CI; 2.64-7.77), for the baby (OR 3.77; 95% CI; 1.53-9.36) and not breastfeeding at 2 (OR 25.73; 95% CI; 11.95-55.40), and 6/8 months postpartum (OR 6.61; 95% CI; 3.21-13.58). Being a passive smoker reduces the intend to breastfeed (OR 1.81; 95% CI; 1.11-2.95), and the practice of breastfeeding at 2 months postpartum (OR 1.94; 95% CI; 1.11-3.37). Women who quit smoking are less likely to suffer complications in pregnancy and childbirth, and are more likely to attend antenatal and breastfeeding classes, and to have babies with higher birth weight.

CONCLUSIONS

Active and passive tobacco consumption has significant implications during pregnancy and postpartum period. Smoking cessation at the beginning of pregnancy reverses much of these effects.

Maternal tobacco exposure and health-related quality of life during pregnancy: a national-based study of pregnant women in China

BACKGROUND

With the increase of the number of smokers, tobacco exposure among pregnant women is becoming more and more common. Pregnant women exposed to first-hand smoke and second-hand smoke are susceptible to physiological and psychological health issues has been proved in previous studies. Nevertheless, there are no enough studies focus on the impact of third-hand smoke during pregnancy. This study aimed to assess and compare health-related quality of life for pregnant women with exposure to first-hand smoke, second-hand smoke, third-hand smoke and non-exposure to tobacco in mainland China.

METHODS

National-based cross-sectional study is based on a questionnaire survey which collects information including demographics, smoking behaviors and self-evaluation. All questionnaires were delivered and collected from August to September 2019. EuroQol group's visual analog scale and EuroQoL Five-dimension Questionnaire were used to collect data in mainland China.

RESULTS

Totally, 15,682 pregnant women were included in this study, among which non-exposure to smoke were 7564 (48.2%), exposed to first-hand smoke, second-hand smoke and third-hand smoke were 89 (0.6%), 2349 (15.0%), and 5680 (36.2%) respectively. Pregnant women without tobacco exposure had the highest EuroQol group's visual analog scale score (mean value = 85.4[SD = 14.0]), while those with first-hand smoke had the lowest score (mean value = 77.4[SD = 22.2]). Among all five dimensions of EuroQoL Five-dimension Questionnaire, there were significant differences of EQ-index among groups with different tobacco exposure in usual activity and anxiety or depression dimensions (p < 0.001).

CONCLUSIONS

Third-hand smoke exposure had close relationship with low health-related quality of life in pregnant women. Moreover, second-hand smoke exposure significantly led more problems on mental dimension of pregnant women.

[Effects of active and/or passive smoking during pregnancy and the postpartum period]

INTRODUCTION

Tobacco smoking may cause adverse effects during pregnancy and postpartum. The aim of this study was to evaluate several repercussions of active and/or passive smoking by the mother at home, during pregnancy, at delivery, as well as for the new born baby and breastfeeding, including the effect of quitting smoking in the first trimester of pregnancy.

METHODS

A prospective longitudinal study was carried out with a sample of 800 pregnant women. Four evaluations were made: first and third trimester of pregnancy, and 2 and 6/8 months postpartum. Sociodemographic, obstetric, health and tobacco consumption information was collected, with biochemical tests being performed to confirm the self-reported abstinence.

RESULTS

Being an active and passive smoker predicted suffering complications in pregnancy (OR 2.50; 95% CI; 1.42-4.35) and delivery (OR 3.10; 95% CI; 1.75-5.51), and also intend not to breastfeed (OR 2.44; 95% CI; 1.35-4.42). Being an active smoker predicted complications at childbirth (OR 5.58; 95% CI; 2.64-7.77), for the baby (OR 3.77; 95% CI; 1.53-9.36) and not breastfeeding at 2 (OR 25.73; 95% CI; 11.95-55.40), and 6/8 months postpartum (OR 6.61; 95% CI; 3.21-13.58). Being a passive smoker reduces the intention to breastfeed (OR 1.81; 95% CI; 1.11-2.95), and the practice of breastfeeding at 2 months postpartum (OR 1.94; 95% CI; 1.11-3.37). Women who quit smoking are less likely to suffer complications in pregnancy and childbirth, and are more likely to attend antenatal and breastfeeding classes, and to have babies with higher birth weight.

CONCLUSIONS

Active and passive tobacco consumption has significant implications during pregnancy and postpartum period. Smoking cessation at the beginning of pregnancy reverses much of these effects.

[Effects of tobacco habit, second-hand smoking and smoking cessation during pregnancy on newborn's health]

BACKGROUND AND OBJECTIVE

Tobacco during pregnancy affects the health of the newborn. The aim was to assess the effect of maternal exposure to active and passive tobacco and of smoking cessation on the risk of preterm deliveries and birth weight, taking into account other risk factors.

PATIENTS AND METHOD

Longitudinal study conducted in 282 healthy pregnant women. General, obstetrical and hematological data were collected as it was the smoking habit during pregnancy. Pregnant women were classified as "exposed to smoke" (active smoker and passive smoker) and "unexposed to smoke" (non-smokers and women who quitted smoking during pregnancy).

RESULTS

A percentage of 59.2 were non-smokers, 18.4% active smokers, 8.5% second-hand smokers and 13.8% had stopped smoking. Unexposed pregnant women who stopped smoking had the same risk of premature deliveries and children with similar birth weight as non-smoker women. Active and second-hand smokers were at higher risk of preterm deliveries than non-smokers (odds ratio [OR] 6.5, 95% confidence interval [95% CI] 1.4-30.8 and OR 6.2, 95% CI 1.0-38.9, respectively); however, higher levels of hemoglobin in the 1st and 3rd trimester exerted a protective effect (OR 0.9, 95% CI 0.8-0.9). Active and second-hand smokers had babies weighing less than non-smokers (around 129 and 178g less, respectively).

CONCLUSIONS

Active or passive exposure to smoke during pregnancy and lower hemoglobin levels are associated with an increased risk of premature deliveries and lower birth weight. Stopping smoking during pregnancy prevents these detrimental effects.

Caspase 3 activity in isolated fetal rat lung fibroblasts and rat periodontal ligament fibroblasts: cigarette smoke induced alterations

Background

Cigarette smoking is the leading cause of preventable death and has been implicated in pathogenesis of pulmonary, oral and systemic diseases. Smoking during pregnancy is a risk factor for the developing fetus and may be a major cause of infant mortality. Moreover, the oral cavity, and all cells within are the first to be exposed to cigarette smoke and may be a possible source for the spread of toxins to other organs of the body. Fibroblasts in general are morphologically heterogeneous connective tissue cells with diverse functions. Apoptosis or programmed cell death is a crucial process during embryogenesis and for the maintenance of homeostasis throughout life. Deregulation of apoptosis has been implicated in abnormal lung development in the fetus and disease progression in adults. Caspases are proteases which belong to the family of cysteine aspartic acid proteases and are key components for downstream amplification of intracellular apoptotic signals. Of 14 known caspases, caspase-3 is the key executioner of apoptosis. In the present study we explored the hypothesis that cigarette smoke (CS) extract activates caspase-3 in two types of fibroblasts, both of which would be exposed directly to cigarette smoke, isolated fetal rat lung fibroblasts and adult rat periodontal ligament (PDL) fibroblasts.

Methods

Isolated fetal rat lung fibroblasts and adult PDLs were used. Cells were exposed to different concentrations of CS for 60 min. Caspase-3 activity and its inhibition by Z-VAD-fmk were measured by caspase-3 fluorometric assay. The effect of CSE on cellular viability was measured using the MTT formazan assay. Caspase-3 expression was detected by western blot analysis and cellular localization of caspase-3 was determined by immunofluorescence using fluorescence microscopy.

Results

It was observed in fetal rat lung fibroblast cells that CSE extract significantly (p<0.05) increased caspase-3 activity and decrease cell proliferation. However, no significant changes in activity or viability were observed in PDLs.

Conclusions

This indicates CS activates caspase-3 the key regulatory point in apoptosis in fetal rat lung fibroblast cells suggesting that smoking during pregnancy may alter the developmental program of fetal lung, jeopardizing the establishment of critical cellular mechanisms necessary to expedite pulmonary maturation at birth.of critical cellular mechanisms necessary to expedite pulmonary maturation at birth.

Indoor smoke and prenatal and childhood growth: The role of (gestational) age

Growth at birth and during infancy predicts several outcomes in the immediate future as well as in the long term. Weight and height are commonly used surrogates of growth, however, infants and young children are constantly growing unlike adults. Hence, weight and height alone are insufficient measures of growth if the time component is not associated with them. Recent studies have investigated the relationship between indoor air pollution and growth using height and weight. In this commentary, I have argued using a directed acyclic graph, that a causal association between indoor pollution exposure and growth at birth cannot be established unless birth weight is adjusted for gestational age. Furthermore, to make any causal inference between growth during the first few years of life and indoor exposure, in addition to age standardization, studies must also account for fetal growth to discount any continuation of prenatal effects, which may be in the causal pathway. A careful consideration is warranted from future studies investigating these relationships.

Exposure to Second-hand Smoke During Pregnancy and Preterm Delivery

Background

Prematurity is an issue related to increasing the neonatal morbidity and mortality and smoking pregnant women cause the risk of low birth weight and prematurity increase, compared to non-smoking ones.

Objectives

This study investigates second-hand smoke (SHS) exposure’s effects over pregnant women on gestational age and birth weight.

Materials and Methods

In this descriptive-analytic study, 205 women referred to both public and private hospitals in the third trimester were questioned about second-hand smoke (SHS) exposure during pregnancy. In addition to birth weight and gestational age, other variables including mother’s education and job and sex of the newborns were also assessed.

Results

Of all 205 women, 43 (20.97%) women exposed to SHS during pregnancy and 162 (79.02%) women did not. In SHS exposure group, 11 infant (25.6%) and in non- SHS exposure group, 17 infant (10.5%), were born prematurely (< 37 weeks) (P = 0.01). Also birth weight of newborn in non-SHS exposure group was 118 gram more than other group but the differences were not significant (P = 0.09).

Conclusions

Our findings showed that the secondhand smoke (SHS) exposure of pregnant women may be significantly associated with early preterm delivery.

Pregnancy, smoking and birth outcomes

This review summarizes the epidemiology and consequences of maternal smoking in pregnancy, with emphasis on the adverse effects on birth outcomes. In developed countries, approximately 15%, and in developing countries, approximately 8% of women smoke cigarettes, and adolescents and women from lower socioeconomic groups are more likely than other women to smoke while pregnant. Maternal smoking during pregnancy is the largest modifiable risk factor for intrauterine growth restriction. A meta-analysis of recent studies showed that the pooled estimate for reduction of mean birthweight was 174 g (95% confidence limits 132-220 g). Other studies confirm a weaker association between maternal smoking and preterm birth. The population attributable risk of low birthweight due to maternal smoking in the UK is estimated to be 29-39%. Tobacco smoke toxins damage the placenta and may lead to placental abruption, abortion or placenta praevia. Infants of mothers who smoke in pregnancy are at an increased risk of respiratory complications including asthma, obesity and, possibly, behavioral disorders. These effects may be dose-related, as there is good evidence that mean birthweight decrements are greater with increased numbers of cigarettes smoked during pregnancy. Cotinine is a useful indicator of tobacco smoke exposure in pregnant women and higher levels in body fluids have been related to lower birthweights. Maternal genetic polymorphisms of the cytochrome P (CYP)450 and glutathione-S-transferase (GST) subfamilies of metabolic genes influence the magnitude of the effect of nicotine exposure on birth outcomes through their influence on nicotine metabolism. Greatly increased risk of cigarette smoke-induced diseases, including low birthweight, has been found in individuals with susceptible genotypes. Interventions to control maternal smoking are also considered.

The impact of intrauterine tobacco exposure on the cerebral mass of the neonate based on the measurement of head circumference

The objective of the study was to assess cerebral mass, based on head circumference measurements in neonates exposed to tobacco smoke in utero, and to determine the relative proportions of the cerebral and body mass. The study included 147 neonates born in the period 2003-2004 at the Princess Anna Mazowiecka University Hospital and admitted to the Neonatal and Intensive Care Department of the Medical University in Warsaw. Subjects were divided into three groups on the basis of maternal status as active, passive, or nonsmokers determined by maternal urinary cotinine concentration and a questionnaire. Neonates whose mothers were active smokers throughout the whole period of pregnancy had a lower head circumference and in consequence a lower cerebral mass significantly more frequently when compared with those whose mothers were nonsmokers, P= 0.002. (Median difference in cerebral mass was 48.27 g.) The risk of lower cerebral mass was 3.9 (1.4-10.8, CI 95%) in the group of neonates whose mothers actively smoked cigarettes during pregnancy. A negative correlation was seen between cerebral mass and maternal urinary cotinine concentration (correlation coefficient r=-23, P= 0.006). The ratio of the cerebral to body mass was similar for neonates in all three groups. Active smoking during pregnancy had a negative effect on the cerebral mass of the neonate, however no such effect was observed in neonates whose mothers were passive smokers. The deficiency in cerebral mass increased with greater smoking intensity. Active smoking by the mother during pregnancy inhibits the growth of the brain as well as that of the body mass of the neonate.

A mutant Ahr allele protects the embryonic kidney from hydrocarbon-induced deficits in fetal programming

BACKGROUND

The use of experimental model systems has expedited the elucidation of pathogenetic mechanisms of renal developmental disease in humans and the identification of genes that orchestrate developmental programming during nephrogenesis.

OBJECTIVES

We conducted studies to evaluate the role of AHR polymorphisms in the disruption of renal developmental programming by benzo(a)pyrene (BaP).

METHODS

We used metanephric cultures of C57BL/6J (C57) mice expressing the Ahr(b-1) allele and B6.D2N-Ahr(d)/J (D2N) mice expressing a mutant allele deficient in ligand binding (Ahr(d)) to investigate molecular mechanisms of renal development. Deficits in fetal programming were evaluated in the offspring of pregnant mice treated with BaP during nephrogenesis.

RESULTS

Hydrocarbon challenge of metanephri from C57 mice altered Wilms' tumor suppressor gene (Wt1) mRNA splice variant ratios and reduced mRNAs of the Wt1 transcriptional targets syndecan-1 (Sdc1) paired box gene 2 (Pax2), epidermal growth factor receptor (Egfr), and retinoic acid receptor, alpha (Rarα). These changes correlated with down-regulation of effectors of differentiation [secreted frizzled-related sequence protein 1 (Sfrp1), insulin-like growth factor 1 receptor (Igf1r), wingless-related MMTV-integration site 4 (Wnt4), Lim homeobox protein 1 (Lhx1), E-cadherin]. In contrast, metanephri from D2N mice were spared hydrocarbon-induced changes in Wt1 splice variant ratios and deficits of differentiation. We observed similar patterns of dysmorphogenesis and progressive loss of renal function at postnatal weeks 7 and 52 in the offspring of pregnant C57 but not D2N mice gavaged with 0.1 or 0.5 mg/kg BaP on gestation days 10-13.

CONCLUSIONS

These findings support a functional link between AHR and WT1 in the regulation of renal morphogenesis and raise important questions about the contribution of human AHR polymorphisms to the fetal origins of adult-onset kidney disease.

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.

Small for gestational age and higher birth weight predict childhood obesity in preterm infants

We sought to determine the association between small for gestational age (SGA), birth weight, and childhood obesity within preterm polysubstance exposed children. We sampled 312 preterm children with 11-year body mass index (BMI; age- and sex-specific) data from the Maternal Lifestyle Study (51% girls, 21.5% SGA, 46% prenatal cocaine, and 55% tobacco exposed). Multinomial regression analyzed the association between 11-year obesity (OBE) and overweight (OW) and SGA, birth weight, first-year growth velocity, diet, and physical activity variables. Overall, 24% were OBE (BMI for age ≥95th percentile) and 16.7% were OW (BMI ≥85th and <95th percentiles). In adjusted analyses, SGA was associated with OW (odds ratio [OR] = 3.4, confidence interval [CI] 1.5 to 7.5). Higher birth weight was associated with OBE (OR = 1.8, CI 1.3 to 2.4) and OW (OR = 1.4, CI 1.1 to 2.0). Growth velocity was associated with OBE (OR = 2.7, CI 1.8 to 4.0) and OW (OR = 1.6, CI 1.1 to 2.4). Low exercise was associated with OBE (OR = 2.1, CI 1.0 to 4.4) and OW (OR = 2.1, CI 1.0 to 4.5). There was no effect of substance exposure on obesity outcomes. Many (41%) of these high-risk preterm 11-year-olds were obese/overweight. Multiple growth-related processes may be involved in obesity risk for preterm children, including fetal programming as indicated by the SGA effect.

Environmental tobacco smoke exposure and perinatal outcomes: a systematic review and meta-analyses

BACKGROUND

While active maternal tobacco smoking has well established adverse perinatal outcomes, the effects of passive maternal smoking, also called environmental tobacco exposure (ETS), are less well studied and less consistent.

OBJECTIVE

To determine to the effect of ETS on perinatal outcomes.

SEARCH STRATEGY

Medline, EMBASE and reference lists were searched.

SELECTION CRITERIA

Studies comparing ETS-exposed pregnant women with those unexposed which adequately addressed active maternal smoking.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed titles, abstracts, full studies, extracted data and assessed quality. Dichotomous data were pooled using odds ratios (OR) and continuous data with weighted mean differences (WMD) using a random effects model.

MAIN RESULTS

Seventy-six articles were included with a total of 48,439 ETS-exposed women and 90,918 unexposed women. ETS-exposed infants weighed less [WMD -60 g, 95% confidence interval (CI) -80 to -39 g], with a trend towards increased low birthweight (LBW, < 2,500 g; RR 1.16; 95% CI 0.99-1.36), although the duration of gestation and preterm delivery were similar (WMD 0.02 weeks, 95% CI -0.09 to 0.12 weeks and RR 1.07; 95% CI 0.93-1.22). ETS-exposed infants had longer infant lengths (1.75 cm; 95% CI 1.37-2.12 cm), increased risks of congenital anomalies (OR 1.17; 95% CI 1.03-1.34) and a trend towards smaller head circumferences (-0.11 cm; 95% CI -0.22 to 0.01 cm).

CONCLUSIONS

ETS-exposed women have increased risks of infants with lower birthweight, congenital anomalies, longer lengths, and trends towards smaller head circumferences and LBW.

The influence of secondhand smoke exposure on birth outcomes in Jordan

This study investigates how secondhand smoke (SHS) exposure influences neonatal birth weight in Jordan, a country with high smoking prevalence. The findings revealed that as the average number of SHS exposure hours per week increased in the second trimester, the neonatal birth weight decreased while holding all covariates constant. Women who reported a higher average number of SHS exposure hours per week from work in the second trimester, home in the third trimester, and outside in the third trimester were at greater risk for having a low birth weight neonate than women who reported a lower average number of SHS exposure hours.

From the American Academy of Pediatrics: Technical report--Secondhand and prenatal tobacco smoke exposure

Secondhand tobacco smoke (SHS) exposure of children and their families causes significant morbidity and mortality. In their personal and professional roles, pediatricians have many opportunities to advocate for elimination of SHS exposure of children, to counsel tobacco users to quit, and to counsel children never to start. This report discusses the harms of tobacco use and SHS exposure, the extent and costs of tobacco use and SHS exposure, and the evidence that supports counseling and other clinical interventions in the cycle of tobacco use. Recommendations for future research, policy, and clinical practice change are discussed. To improve understanding and provide support for these activities, the harms of SHS exposure are discussed, effective ways to eliminate or reduce SHS exposure are presented, and policies that support a smoke-free environment are outlined.

Smoking trends before, during, and after pregnancy among women and their spouses

BACKGROUND

Pregnancy and childbirth can act as strong factors motivating parents to spontaneously quit smoking. The aim of the present survey was to establish smoking cessation guidelines for this group. The objectives were to clarify the smoking status of parents before, during and after pregnancy, as well as the factors associated with continuous smoking during pregnancy and post-partum smoking relapse among women who had stopped smoking during pregnancy.

METHODS

A cross-sectional survey with self-administered questionnaires was conducted for the parents of the 908 infants who participated in the official medical and dental examination for 18-month-old infants in Itabashi ward, Tokyo, Japan.

RESULTS

The prevalence of smoking among women before, during pregnancy, and at post-partum 18 months at 95% confidence intervals was 29.3% (23.3-35.3%), 9.8% (3.0-16.6%), and 23.1 (16.8%-29.4%), and among their spouses it was 64.3% (60.0-68.6%), 58.1% (53.4-62.7%), and 58.2% (53.5-62.8%), respectively. The positive factors associated with smoking among pregnant women were marriage to a smoker, less education, under stress, and part-time employment rather than unemployment. The positive factors associated with smoking relapse after childbirth among women were breast-feeding <6 months and age under 30 years.

CONCLUSION

Compared with Western countries, the rate of smoking cessation during pregnancy was relatively high in Japan. It is necessary that smoking cessation intervention and support for men be initiated at the early stages of their spouses' pregnancies. These observations could influence the targeting and design of maternal smoking intervention.

Maternal cardiac output between 11 and 13 weeks of gestation in the prediction of preeclampsia and small for gestational age

OBJECTIVE

To investigate maternal cardiac output in the first trimester as a predictor of preeclampsia and delivery of small for gestational age (SGA) infants.

METHODS

In women attending for routine care between 11(+0) and 13(+6) weeks of gestation, we recorded maternal variables and measured cardiac output by echocardiography. We compared cardiac output in those that developed preeclampsia (n=83), pregnancy-induced hypertension (PIH) (n=87), or SGA (n=532) with those unaffected by preeclampsia, PIH, or SGA (n=3,591). Regression analysis was used to first determine which of the factors among the maternal variables were significant predictors of cardiac output in the unaffected group and, secondly, to predict each complication by a combination of maternal variables and cardiac output.

RESULTS

In the unaffected group, cardiac output increased with gestation and maternal weight and decreased with maternal age. Cardiac output was higher in parous women, in cigarette smokers, in those taking antihypertensive or beta-mimetic medications, and in those conceiving after in vitro fertilization, and lower in women of Afro-Caribbean origin. Compared with the unaffected group, cardiac output was significantly higher in the preeclampsia and PIH groups and lower in the SGA group. In screening by cardiac output and maternal variables, for a 10% false-positive rate, the detection rates were 43.4% for all preeclampsia, 52% for preeclampsia without SGA, 23.3% for PIH, and 23.9% for SGA.

CONCLUSION

In pregnancies complicated by preeclampsia, PIH, and SGA, alterations in maternal cardiac output predate the clinical onset of the disorders by several months. Maternal cardiac output in the first trimester is increased in women who develop preeclampsia and decreased in women who deliver SGA infants.

LEVEL OF EVIDENCE

II.

The effects of air pollution and smoking on placental cadmium, zinc concentration and metallothionein expression

This study is designed to determine the placental zinc (Zn) and cadmium (Cd) levels in mothers who were smokers, mothers who were thought to be exposed to air pollution, and mothers who were non-smokers and to investigate the relationship between the expression of placental metallothionein (MT) binding these metals and blood progesterone level. Placental Zn and Cd levels were measured by atomic absorption spectrometry. Presence of placental MT was determined immunohistochemically. Placental changes were examined by light microscope after H&E and PAS staining. Immunohistochemical MT staining of syncytiotrophoblastic and villous interstitial cells were scored as positive or negative. Among the 92 mothers included in the study, 33 were smokers (Group I), 29 had been exposed to air pollution (Group II) and 30 were non-smoker rural residents who had never been exposed to air pollution (Group III). Mean off-spring birth weight of 3198.62+/-380.01 g and mean placenta weight of 561.38+/-111.55 g of Group II were lower when compared with those of other two groups. In Group I, mean placental Cd and Zn were 0.063+/-0.022 microg/g and 39.84+/-15.5 microg/g, respectively, being higher than in other groups. In Group II, mean placental Cd and Zn levels were higher than those of Group III. Blood progesterone levels of subjects in Group I (121 ng/ml) were the lowest of all groups. While the mean count of villi was the highest in Group III; the highest mean count of syncytial knots was in Group II. Thickening of vasculo-syncytial membrane was most prominent in Group I. Similarly, MT staining was positive and very dense in 72.7% (24/33) of cases in Group I (p<or=0.05). MT staining was positive in 69.0% (29/20) and denser in Group II cases compared to 36% (11/30) in Group III (p<or=0.05). This study showed that smoking increased Cd levels in placenta and accompanied an increase in placental MT expression immunohistochemically. The effects of exposure to air pollution are equally harmful as smoking related effects.

Smoking in early gestation or through pregnancy: a decision crucial to pregnancy outcome

OBJECTIVE

To assess maternal risk profile and pregnancy outcome of women who continued to smoke, reduced smoking to less than five cigarettes per day or did not smoke during pregnancy.

METHODS

We analyzed a population-based database of 26,414 singleton pregnancies from 1989 to 2001. Odds ratios (ORs) for adverse pregnancy outcomes were obtained from multiple logistic regression models.

RESULTS

The prevalence of smoking in early pregnancy was 25.7% and went down to 12.7% at 20 weeks of pregnancy. Women who smoked were more often young, primiparous or unmarried, used alcohol and more often had prior pregnancy terminations than women who did not smoke. Women who reduced smoking were mostly primiparous, and they also quit using alcohol. Continuing to smoke was associated with elevated risks of small-for-gestational-age infants (SGA) (OR 2.11), preterm birth (OR 1.15) and perinatal death (OR 1.15). SGA was avoided by reducing smoking, but not prematurity (OR 1.18) or elevated risk of perinatal death (OR 1.18).

CONCLUSION

Smoking in early gestation and through pregnancy is associated with adverse pregnancy outcomes, and some of the harmful effects can be avoided by reducing smoking, although the behavioral risk profile of those who reduced smoking is closer to that of smokers than of non-smokers.

Combined effects of maternal smoking status and dietary intake related to weight gain and birth size parameters

OBJECTIVE

To investigate the interaction of smoking status and dietary intake during pregnancy and its relationship to maternal weight gain and birth size parameters.

DESIGN

An observational prospective study.

SETTING

Free-living conditions.

POPULATION

Four hundred and eight healthy pregnant Icelandic women.

METHODS

Maternal smoking status, lifestyle factors and dietary habits were evaluated with questionnaires. Intake of foods and supplements was also estimated with a semiquantitative food frequency questionnaire for the previous 3 months. All questionnaires were filled out between 11 and 15 weeks and between 34 and 37 weeks of gestation. Smoking status in relation to optimal and/or excessive weight gain during pregnancy was represented with logistic regression controlling for potential confounding factors.

MAIN OUTCOME MEASURES

Maternal weight gain, smoking status, dietary intake and birthweight.

RESULTS

Women who smoked throughout pregnancy were unlikely to gain optimal weight or more (OR 0.51, 95% CI 0.27-0.97), whereas smoking cessation in connection with pregnancy ('former smokers') doubled the risk of excessive weight gain (OR 2.03, 95% CI 1.24-3.35). The latter association was no longer significant after adjustment for dietary factors and other confounding factors. Former smokers ate the least amount of fruit and vegetables (fruit: 129 versus 180 and 144 g/day (median), P= 0.038; vegetables: 53 versus 76 and 72 g/day, P= 0.026 for former smokers, nonsmokers and smokers, respectively). Birthweight was lowest among infants born to smokers, but birthweight was similar for former smokers and nonsmokers (3583 +/- 491 g versus 3791 +/- 461 g and 3826 +/- 466 g, respectively; P= 0.003).

CONCLUSIONS

Smoking cessation in early pregnancy or pre-pregnancy is not associated with low birthweight. It is, however, associated with excessive maternal weight gain and a low fruit and vegetable intake.

Interactions between fetal HLA-DQ alleles and maternal smoking influence birthweight

Maternal smoking during pregnancy inhibits fetal growth, and is a major cause of childhood and adult morbidity, including increased risks of cardiovascular disease and diabetes. However, the use of birthweight as a proxy for future smoking-related morbidity is hindered by its wide variability, suggesting a role for other birthweight-modifying factors. We report here, for the first time, that interactions between specific fetal HLA-DQA1 and DQB1 alleles and maternal smoking can influence birthweight. We compared mean birthweights of a series of term, HLA-DQ typed white UK newborns (n = 552) whose mothers had either smoked (n = 211) or not smoked (n = 341) during pregnancy. Maternal smoking during pregnancy resulted in an average birthweight reduction of 244 g, but the combined effects of maternal smoking and fetal DQA1*0101 or DQB1*0501 alleles resulted in a 230 and 240 g further reduction in mean birthweight, respectively, resulting from interactions between smoking and these DQ types. Other fetal DQ allele-specific interactions with maternal smoking are suggested by a "protective" effect on smoking-associated birthweight reduction in newborns typing for DQA1*0201 and DQB1*0201. Our results suggest biological interactions between maternal cigarette smoking during pregnancy and specific fetal DQ alleles that affect fetal growth. The precise nature of these interactions merits further investigation, as knowledge of fetal HLA-DQ type may be useful in refining risk estimates of severe fetal growth restriction because of maternal smoking during pregnancy.

Smoking specifically induces metallothionein-2 isoform in human placenta at term

Recently, we reported the presence of higher levels of metallothionein (MT) in placentas of smokers compared to non-smokers. In the present study, we designed experiments to separate and evaluate two isoforms of MT (MT-1 and MT-2) in placentas of smokers and non-smokers. Metallothionein was extracted and separated by ion-exchange high performance liquid chromatography (HPLC), previous saturation with cadmium chloride. Two peaks eluting at 6 and 12.5 min, corresponding to MT-1 and MT-2, respectively, were obtained. Metallothionein present in both peaks was identified by Western blot analysis using a monoclonal antibody directed against MT-1 and MT-2. Each isoform concentration was calculated after measuring its cadmium content by atomic absorption spectrometry with inductively coupled-plasma. In placentas of smokers, MT-2 levels increased by seven-fold compared to non-smokers, whereas MT-1 was not changed. Total placental cadmium and zinc concentrations, determined by atomic absorption spectrometry and neutron activation analysis, respectively, were higher in smokers. Metallothioneins levels were clearly in excess to bind all cadmium ions present in placentas. However, most of placental zinc remains unbound to MTs, although as much as twice zinc ions could be bound to MT in smokers. In conclusion, MT-2 is the main isoform induced by smoking, suggesting that this isoform could be involved in placental cadmium and zinc retention. This fact, which could contribute to reduce the transference of zinc to the fetus, may be associated to detrimental effects on fetal growth and development.

[Birth weight and familial smoking]

INTRODUCTION

Tobacco smoking during pregnancy is an important risk factor in the pediatric population and has been associated with an increase in low birth weight (LBW) infants.

PATIENTS AND METHODS

We carried out a retrospective case-control study of infants admitted to the Infants Department of the Hospital Universitario Infantil Niño Jesús in Madrid. Data from 2370 infants admitted to the hospital between 2002 and 2004 were collected.

RESULTS

The odds ratio (OR) for having a LBW infant was 1.42 (95 % CI: 1.017-1.985) among mothers who smoked during pregnancy and was 1.37 (95 % CI: 1.014-1.863) among women whose partners smoked. Gestational age was also a predictive factor of birth weight: the OR was 0.585 (95 % CI: 0.545-0.628). No significant differences for risk of LBW were found between sexes (OR: 1.25; 95 % CI: 0.934-1.671).

CONCLUSIONS

Our results should reinforce the importance of smoking prevention during and after pregnancy in both parents, which could reduce many complications in children's health with a high medical, social and economic cost.

Metals content in placentas from moderate cigarette consumers: correlation with newborn birth weight

Cigarette consumption during pregnancy produces deleterious effects in both, mother and fetus, some of them due to the presence of toxic elements in cigarette smoke, such as cadmium. Placenta constitutes a dual-purpose specimen for evaluating the pollutant burden exerted on the mother as well as on the fetus. The main objective of this study was to establish a correlation between placental concentration and distribution of some metal elements and birth weight of neonates delivered by mothers, who were either moderate smokers or nonsmokers. Forty nonsmoking and moderate smoking pregnant women paired per age, parity, weight, height and body mass index were selected. Smoking was assessed by self-reported cigarette consumption during pregnancy and urine cotinine concentration before delivery. Placental metal concentrations were evaluated by atomic absorption spectrometry (copper and cadmium) and neutron activation analysis (zinc and iron). Newborns from smokers had lower birth weights compared to infants from nonsmokers. Birth weights were correlated with placental cadmium concentrations in both, smokers and nonsmokers. Placental zinc and cadmium of smokers were mainly located at the maternal side and their levels were higher than those found in nonsmoker's placentas. In addition, all metal nutrient/pollutant ratios were decreased in the smoker group. In this first study performed in our region, we found that moderate smoking mothers deliver neonates with decreased birth weight and highly correlated to placental cadmium concentration. Decreased metal nutrient/pollutant ratios, a condition here found in smokers, may indicate a placental dysfunction, contributing to impair birth weight.

Increased levels of metallothionein in placenta of smokers

Experiments were designed to evaluate and compare metallothionein (MT), zinc and cadmium levels in human placentas of smoking and non-smoking women. Smoking was assessed by self-reported cigarette consumption and urine cotinine levels before delivery. Smoking pregnant women with urine cotinine levels higher than 130 ng/ml were included in the smoking group. Determination of placental MT was performed by western blot analysis after tissue homogenization and saturation with cadmium chloride (1000 ppm). Metallothionein was analyzed with a monoclonal antibody raised against MT-1 and MT-2 and with a second anti mouse antibody conjugated to alkaline phosphatase. Zinc and cadmium were determined by neutron activation analysis and atomic absorption spectrometry respectively. Smokers showed higher placental MT and cadmium levels, together with decreased newborn birth weights, as compared to non-smokers. The semi-quantitative analysis of western blots by band densitometry indicated that darker bands corresponded to MT present in smokers' samples. This study confirms that cigarette smoking increases cadmium accumulation in placental tissue and suggests that this element has a stimulatory effect on placental MT production.

Maternal/newborn GSTT1 null genotype contributes to risk of preterm, low birthweight infants

OBJECTIVES

Maternal cigarette smoke exposure during pregnancy has been identified as a risk factor for prematurity and low birthweight. However, little is known about genetic susceptibility and possible interactions with cigarette smoking which may increase risk of these events.

METHODS

Maternal peripheral and umbilical cord blood samples from 955 mother/newborn pairs were genotyped for a panel of phase I/II metabolic enzymes responsible for the metabolism of tobacco related mutagens and carcinogens in order to evaluate the association with premature birth.

RESULTS

As reported previously, maternal cigarette smoking during the last trimester was significantly associated with premature birth. In addition, maternal glutathione S-transferase T1 (GSTT1) null genotype also increased risk of premature birth. Risk was further elevated among subjects with the combination of maternal and newborn GSTT1 null genotype with or without maternal cigarette smoke.

CONCLUSIONS

These observations suggest that women and/or newborns with the GSTT1 null genotype who are exposed to cigarette smoke during pregnancy are at elevated risk for premature delivery. The ability to identify high-risk women by genotyping has potential for reducing the frequency of premature births, a major public health concern.

Cigarette smoking during pregnancy in rural Nepal. Risk factors and effects of beta-carotene and vitamin A supplementation

OBJECTIVE

We examined risk factors of smoking and the association between smoking and pregnancy-related and 6-month infant mortality in rural Nepal, where 30% women reported smoking during pregnancy.

DESIGN

Cross-sectional analysis of risk factors associated with smoking status and health consequences of smoking, using prospective data collected as part of a randomized community trial to examine the effect of maternal vitamin A or beta-carotene supplementation on maternal mortality.

SETTING

Rural, southeastern plains of Nepal.

SUBJECTS AND METHODS

A total of 17 767 women contributed at least one pregnancy during 3.5 y of the study. Data on cigarette or bidi (rolled tobacco) smoking were collected using a 7-day recall, twice during pregnancy. Associations between smoking status and maternal diet, morbidity profile, household socioeconomic status and serum concentration of retinol, carotenoids and tocopherols were examined. Further, relative risk (RR) and 95% confidence intervals (CI) were calculated to estimate supplement effects on pregnancy-related mortality, stratified by smoking status during pregnancy.

RESULTS

Smokers were more likely to be older, illiterate and poor compared to nonsmokers. Fruit and vegetable consumption among smokers and nonsmokers did not vary. However, smokers were more likely to consume meat/fish/eggs and less likely to consume milk than nonsmokers. They were also more likely to report symptoms of vaginal bleeding, edema, severe headache and convulsions during pregnancy relative to nonsmokers. Mortality per 100,000 pregnancies appeared to be higher among smokers than nonsmokers in the placebo group (915 vs 584, RR=1.57, 95% CI: 0.80-3.08). beta-Carotene supplementation reduced pregnancy-related mortality both among smokers (RR=0.31 95% CI: 0.11-0.89) and nonsmokers (RR=0.41, 95% CI: 0.19-0.89). Similar results obtained with vitamin A supplementation were not statistically significant. Infant mortality up to 6 months was approximately 30% higher among smokers compared to nonsmokers in the placebo group both before and after adjusting for confounding factors. Neither supplement given to women reduced infant mortality.

CONCLUSIONS

Cigarette smoking during pregnancy is associated with an increased risk of maternal and infant mortality in rural Nepal. beta-Carotene and to some extent vitamin A may reduce the risk of pregnancy-related mortality, but not infant mortality, among both smokers and nonsmokers.

Epidemiology of substance use disorders in women

Significant gender differences exist in the prevalence of substance use disorders in the United States. There is a trend among boys and girls aged 12 to 17 years toward comparable rates of use and initiation for alcohol, cocaine, heroin, and tobacco. If this trend continues, over time there may be a narrowing of the male-to-female prevalence ratios of substance abuse in the older age groups. This possibility is particularly disturbing because women have a heightened vulnerability to medical, physical, mental, and social consequences of substance use. Women also carry additional unique risks during pregnancy because of the effect on neonates. In addition, they have certain gender-specific cancer risks. Given this and the declining age of initiation of substance use in women, prevention and treatment efforts especially geared toward women (eg, education of all medical and paramedical staff, screening in primary care clinics, detection of drug use early in pregnancy or before conception, brief interventions and treatment programs that integrate women's needs) are exceedingly important to stop and ultimately reverse this growing trend.

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.

The influence of simultaneous whole body exposure to cigarette smoke and low-protein diet feeding on fertility, reproduction, and progeny of rats

The aim of the present study was to evaluate the toxicological influence of different concentrations of tobacco smoke and low-protein diet on fertility, reproduction, and survival of offspring of Wistar female rats. We studied three generations, two litters in each. There were 192 animals in parent generation. Animals were exposed to three different concentrations of tobacco smoke that were reflected by the carbon monoxide (CO) concentration (500, 1000, and 1500 mg CO/m3 air) during 11 weeks (six before and two weeks during mating, and three weeks of pregnancy). Additionally, animals were divided into two subgroups that were fed normal or low-protein diet. In the present study, we concentrated on the indices describing the reproduction ability, fertility, and rearing of pups of mothers exposed to tobacco smoke. The parameters of newborns survival were estimated also. We concluded that neither tobacco smoke exposure nor the low-protein diet changed the duration of pregnancy. The tobacco smoke in all doses and low-protein diet had a negative influence on fertility, reproduction, and survival of newborns from exposed mothers. This influence was mainly attributed to the tobacco smoke exposure. The levels of carboxyhaemoglobin were increasing with increasing tobacco smoke concentration.

Position of the American Dietetic Association: nutrition and lifestyle for a healthy pregnancy outcome

It is the position of the American Dietetic Association that women of childbearing potential should maintain good nutritional status through a lifestyle that optimizes maternal health and reduces the risk of birth defects, suboptimal fetal growth and development, and chronic health problems in their children. The key components of a health-promoting lifestyle during pregnancy include appropriate weight gain; consumption of a variety of foods in accordance with the Food Guide Pyramid; appropriate and timely vitamin and mineral supplementation; avoidance of alcohol, tobacco, and other harmful substances; and safe food-handling. Prenatal weight gain within the Institute of Medicine (IOM) recommended ranges is associated with better pregnancy outcomes. The total energy needs during pregnancy range between 2,500 to 2,700 kcal a day for most women, but prepregnancy body mass index, rate of weight gain, maternal age, and physiological appetite must be considered in tailoring this recommendation to the individual. The consumption of more food to meet energy needs and the increased absorption and efficiency of nutrient utilization that occurs in pregnancy are generally adequate to meet the needs for most nutrients. However, vitamin and mineral supplementation is appropriate for some nutrients and situations. This statement also includes recommendations pertaining to use of alcohol, tobacco, caffeine, street drugs, and other substances during pregnancy; food safety; and management of common complaints during pregnancy and specific health problems. In particular for medical nutrition therapy, pregnant women with inappropriate weight gain, hyperemesis, poor dietary patterns, phenylketonuria (PKU), certain chronic health problems, or a history of substance abuse should be referred to a qualified dietetics professional.

Estimation of environmental tobacco smoke exposure during pregnancy using a single question on household smokers versus serum cotinine

Environmental tobacco smoke (ETS) exposure has been studied in relation to many diseases. The ability of a study to find an association between exposure and disease is, in part, determined by the accuracy of the exposure measure. This study examined how accurately one question, the number of smokers in the household, asked at birth, predicts ETS exposure in pregnant nonsmokers as assessed by serum cotinine. Blood specimens, drawn at 15-19 weeks gestation, from 783 women who participated in a prenatal screening program in California in 1992 were analyzed for cotinine. Serum cotinine was significantly correlated with the number of smokers in the household (r=0.35, P<0.001, geometric mean cotinine (nanograms per milliliter) for 0 smokers=0.06, 1 smoker=0.18, 2 or more smokers=0.29). Using multiple regression, the number of smokers in the household accounted for 11% of the variation in serum cotinine. Cotinine concentrations were twice as high in women living with one or more smokers compared to women not living with a smoker, when reported exposure (0 or >0 h) at home, work and other places was similar. Thus, the number of household smokers can account for a statistically significant amount of variation in serum cotinine and omission of this information would result in an underestimation of ETS exposure. Although use of this question alone does not provide an adequate estimation of ETS exposure as determined by serum cotinine, the results of this study indicate that this question is an important component of assessing ETS exposure.

Drugs of abuse in pregnancy

Care for the drug-using pregnant woman is being increasingly recognized as part of the obstetrician's role. There is great potential for improvement in provision of services for this group of women, partly because traditionally our antenatal clinics have not been perceived as being conducive to disclosure regarding drug use, but also because hard data and, indeed, randomized controlled trials on the subject, are scarce.From the little evidence available, and from our own experience in this area, we have attempted to outline the main problems encountered in the antenatal, intrapartum and postnatal periods with each of the main drugs of abuse and the management thereof. It is important to note that we include cigarette smoking and alcohol, probably the most commonly used drugs in pregnancy, and recognize that the picture is wider than the stereotypical emaciated intravenous heroin addict. Where possible, evidence from trial data is included, but much of the what is quoted is descriptive from personal experience from ourselves and others working in the field.

Prenatal active or passive tobacco smoke exposure and the risk of preterm delivery or low birth weight

We examined the association of exposure to environmental tobacco smoke with birth weight and gestational age in a large, prospective study. We also compared these endpoints between infants of active maternal smokers and those of non-smoking, non-ETS exposed women. Pregnant women were interviewed by telephone during the first trimester, and pregnancy outcome was determined for 99%. Among the 4,454 singleton live births that could be linked to their birth certificate, we confirmed increased risks of low birth weight and small for gestational age with heavier maternal smoking (> 10 cigarettes/day), as well as noting an increased risk for "very preterm" birth (< 35 weeks). These associations were generally stronger among infants of older (> or = 30 years) than those of younger mothers, as well as among non-whites. High environmental tobacco smoke exposure (> or = 7 hours/day in non-smokers) was moderately associated with low birth weight (adjusted odds ratio (AOR) 1.8, 95% confidence limits (95% CL) = 0.82, 4.1), preterm birth (AOR 1.6, 95% CL = 0.87, 2.9), and most strongly with very preterm birth (AOR 2.4, 95% CL = 1.0, 5.3). These associations were generally greater among non-whites than whites. The data support earlier studies suggesting that prenatal environmental tobacco smoke exposure, in addition to maternal smoking, affects infant health.

Growth from birth to early adolescence in offspring prenatally exposed to cigarettes and marijuana

Weight, height, and head circumference were examined in children from birth to early adolescence for whom prenatal exposure to marijuana and cigarettes had been ascertained. The subjects were from a low-risk, predominantly middle-class sample participating in an ongoing longitudinal study. The negative association between growth measures at birth and prenatal cigarette exposure was overcome, sooner in males than females, within the first few years, and by the age of six, the children of heavy smokers were heavier than control subjects. Pre and postnatal environmental tobacco smoke did not have a negative effect upon the growth parameters; however, the choice of bottle-feeding or shorter duration of breast-feeding by women who smoked during pregnancy appeared to play an important positive role in the catch-up observed among the infants of smokers. Prenatal exposure to marijuana was not significantly related to any growth measures at birth, although a smaller head circumference observed at all ages reached statistical significance among the early adolescents born to the heavy marijuana users.

The relationship in neonates between clinically measured head circumference and brain volume estimated from head CT-scans

OBJECTIVE

To determine if the frontal-occipital head circumference correlates with brain volume on CT and to investigate correlations between the volumes of different brain subdivisions in live neonates.

METHODS

Records were studied from 27 neonates with anatomically normal head CT-scans which were ordered for clinical reasons, and which were performed at Johns Hopkins Hospital. Clinical data were abstracted from medical records. Brain volumes were estimated by digitizing the structures of interest on each slice of head CT-scans.

RESULTS

In this sample of 27 infants with a mean birth weight of 3000.4 +/- 668 g, mean head circumference of 33.5 +/- 1.8 cm, and mean gestational age of 37 weeks and 4 days +/- 24 days, the mean of total brain volume was 333.0 +/- 78.3 ml. The correlation between clinically measured head circumference and total brain volume was 0.55 (P < 0.003). Regression of total brain volume on head circumference and its second and third powers accounted for 43% of the variation in total brain volume. Other predictor variables, namely infant race, sex, gestational age, and maternal age, were not significant in this regression once head circumference was included. The slope of the cubic function of head circumference as a predictor of brain volume was greatest below the mean head circumference of 33.5 cm. Brain volume leveled off at head circumferences greater than the mean.

CONCLUSION

Head circumference is a powerful predictor of total brain volume in the neonate: below the approximate head-circumference mean of 33.5 cm, smaller head circumference indicates smaller total brain volume.

Maternal cocaine use and cigarette smoking in pregnancy in relation to amino acid transport and fetal growth

This review covers the weight of evidence that shows the association of cocaine and cigarette smoking in pregnancy with the impaired transplacental amino acid transport which might give rise to fetal growth restriction (IUGR). Vasoconstrictive effects of both cocaine and nicotine on the placental vasculature are clearly not the only cause for inhibition of placental amino acid uptake and transfer. In vitro studies strongly suggest that cocaine decreases the activity of placental amino acid transport system A and system N, and possibly system l and system y(+), while nicotine decreases the activity of system A. These findings are supported by cordocentesis studies in human IUGR pregnancies not resulting from drug abuse. More work is needed to be done in order to understand the potential additive or synergistic effect of cocaine and cigarette smoking on fetal growth and to determine the underlying cellular mechanisms of interaction with placental amino acid transporters.

The experimental investigations of the toxic influence of tobacco smoke affecting progeny during pregnancy

1. Tobacco smoke contains around 4000 substances, most of which are described as toxic, and they may have an influence on the development of progeny. 2. The present studies concentrate on the measurement and calculation of indices describing the new-born's survival, rearing of pups, weight of foetuses, young animals, placenta and females in relation to different doses of tobacco smoke (carbon monoxide levels). The morphological studies of placenta, foetal and newborn lungs were done as a supplement. Biochemical placenta study was also done. 3. The results of the experiment proved that some indices for animals in groups which were passively exposed to the highest concentrations of tobacco smoke were lower, others fluctuated (4 day, 12 day and total survival) and some did not reveal any changes (rearing). Direct correlation between maternal passive exposure to tobacco smoke and the presence of acute respiratory distress syndrome symptoms in new-borns was observed. A decrease of body weight of pregnant females passively exposed to tobacco smoke was also observed. An increase of placenta-foetal factor was found. A decrease of rat weight was observed after passive exposure to tobacco smoke. 4. We concluded that there is correlation between passive exposition to tobacco smoke during pregnancy and delayed lung maturation in the offspring. Exposure of the pregnant rats to cigarette smoke increases the activity of isocitric and glucose-6-phosphate dehydrogenases in placenta.

Maternal passive smoking during pregnancy and fetal developmental toxicity. Part 1: gross morphological effects

1. Prenatal exposure of human fetus to tobacco smoke through maternal passive smoking has been epidemiologically linked to reduced birth weight, enhanced susceptibility to respiratory diseases and changes in immune system. However, no data exists indicating teratogenicity of involuntary smoking. Since sidestream smoke of cigarettes makes the most constituent of whole smoke inhaled by nonsmokers, we performed experiments to determine whether passive inhalation of sidestream smoke by rats causes malformations in newborns. 2. Pregnant 230 - 300 g Wistar rats were each placed in a 150 dm3 glass chamber with two holes, each 3 cm in diameter in two opposite walls to provide unforced exchange of fresh air. A third hole was connected to an automatic smoking machine. The head of a commercial filter blond cigarette (13 mg Tar, 0.9 mg Nicotine) was introduced to the chamber through this later hole. Cigarettes were smoked by smoking machine at the rate and volume resembling human smoking and the mainstream smoke was separately collected and discarded. Each rat thus received the sidestream smoke self-diluted in the chamber air. Experiments were performed with either 1, 2, 3 or 4 cigarettes/day during either first, second or third week of a total 21-day pregnancy period. The interval between smoking of cigarettes was 2 h. 3. COHb in blood of negative controls was about 1.2% and after exposure to 1 or 4 cigarettes were 6% and 12.2%, respectively. A dose-dependent reduction of birth weight was observed in newborns (P<0.001); bitemporal diameters and body lengths were reduced accordingly. No macroscopically visible gross anomaly could be observed. After removing the fat tissue and staining the skeleton with alizarin, a widespread ossification retardation could be observed in all exposed groups regardless of the dose. Such a retardation was not limited to a particular bone. 4. These results support epidemiologic data on developmental toxicity of passive smoking and further provide evidence on an unfavorable osteopathic effect of sidestream exposure of mother on fetal development.

Evidence for an association between environmental tobacco smoke exposure and birthweight: a meta-analysis and new data

Because of the strong association of active smoking with fetal growth retardation, increasing interest has focused on whether there is also an association with exposure to environmental tobacco smoke (ETS). We examined this issue in a retrospective study and by conducting a review of the literature and data pooling. In our study, nonsmoking women with singleton livebirths born in 1986-87 (n = 992) provided information on exposure to ETS for 1 h or more per day and paternal smoking. The risk of low birthweight (LBW, < 2500 g) was not increased in infants of ETS-exposed women, but there was a somewhat increased risk for LBW at term (adjusted odds ratio [OR] 1.8, 95% confidence interval [CI] 0.6, 4.8) and small-for-gestational-age (< 10th percentile of weight; OR = 1.4, 95% CI = 0.8, 2.5). These results were in the range of 16 other studies in the literature that had odds ratios from 1.0 to 2.2. A weighted average of the results of all studies on LBW at term or small-for-gestational-age yielded a pooled estimate of 1.2 [95% CI = 1.1, 1.3] in nonsmoking women. The pooled estimate of mean birthweight indicated a decrement of 28 g with ETS exposure of nonsmoking women [95% CI = -41, -16], with a greater decrement (about 40 g) seen among more homogeneous studies.

Parental smoking and risk factors for cardiovascular disease in 10- to 12-year-old children

OBJECTIVE

Smokers have multiple adverse health-related behaviors and an increased risk of cardiovascular disease. We examined whether health behaviors in parents who smoke may influence children's health behaviors.

STUDY DESIGN

Cross-sectional data from 10- to 12-year-olds (n = 800) entering a trial of health promotion programs.

RESULTS

Smoking in children was independently associated with maternal (odds ratio 2.1, confidence interval 1.2, 3.8) and paternal smoking (odds ratio 2.1, confidence interval 1.2, 3.7) and was less likely in girls (odds ratio 0.4, confidence interval 0.2, 0.6). Maternal smoking and paternal smoking were additive predictors in children of lower physical activity (P = .0013 for mothers; P = .0476 for fathers) and more television watching (P = .0335 for mothers; P = .0241 for fathers). Children's fat intake was significantly greater if either parent smoked. Children's body mass index (P = .0183) and waist-to-hip ratio (P = .0009) were significantly greater if mothers smoked.

CONCLUSIONS

Poor health behaviors associated with smoking in parents, particularly mothers, are likely to influence children's long-term risk of having lifestyle diseases. The results may also explain some of the apparent effects attributed to passive smoking in families.

Etiologies of fetal growth restriction

We have presented here are a long list of conditions associated with an increased incidence of fetal growth restriction. Missing from much of the literature on FGR are data that would allow more informed counseling of patients in terms of predicting their risk of carrying a pregnancy complicated by FGR. For example, very little has been published on the chances of having an infant with FGR in a woman suffering from SLE or chronic hypertension. Future studies of FGR should address these issues so that clinicians may counsel their patients properly.

Prediction of the outcome of growth at 2 years of age in neonates with intra-uterine growth retardation

The aim of the study was to identify at birth, in infants showing intra-uterine growth retardation (IUGR), any parameters correlative with the increase in height SDS during the first 2 years of life and with short stature at 2 years of age, and to determine whether the sensitivity and specificity of such parameters would permit their use as predictors of short stature at 2 years of age. Two cohorts of children born with IUGR with birth weight < 3rd percentile, were studied. In the first group of 317 children selected at birth, 224 were effectively followed up to 2 years of age (group 1) and the second group of 48 children was evaluated at 2 years of age for short stature related to IUGR (group 2). Perinatal history, auxological data at birth and parental height were monitored in a prospective study for the group 1 children and in a retrospective study for the group 2 children. By 2 years of age, 8% of the 224 children followed (group 1), presented short stature (< or = 2 SDS). In a multiple linear regression model, gestational age, birth length (SDS), target height (SDS) and maternal tobacco consumption were found to be the strongest predictors of the magnitude of the height gain (SDS) during the first 2 years of life. Using these parameters 47% of the variability of the height gain (SDS) during the first 2 years of life could be explained at birth. Moreover, logistic regression analysis showed three risk factors at birth for short stature by 2 years of age: reduced gestational age due to premature birth (adjusted odd ratio (O.R.) = 2.10; 95% C.I. = 1.06-4.14), the greater the difference (for each S.D.) between birth length (SDS) and target height (SDS) (O.R. = 1.93; 95% C.I. = 1.40-2.66) and although as a borderline significant factor, maternal tobacco consumption (O.R. = 1.58; C.I. 95% = 0.81-3.07). Non-parametric discriminant analysis was used to investigate whether short (< or = -2 SDS) or normal stature (> -2 SDS) at 2 years could be predicted at birth using gestational age (weeks), birth length (SDS), target height (SDS) and maternal tobacco consumption as discriminant variables. We found that this discriminant model correctly predicted at birth the short stature of 57 of 59 children at 2 years of age (sensitivity 97%) and the normal stature of 142 of 159 children at 2 years of age (specificity 89%). In conclusion, an accurate prediction of short stature by 2 years of age is feasible at birth in the IUGR neonate.