Maternal smoking during pregnancy and child outcomes: real or spurious effect?

Fetal Exposure to Tobacco Metabolites and Depression During Adulthood: Beyond Binary Measures

BACKGROUND

Sibling studies of maternal smoking during pregnancy and subsequent risk of depression have produced mixed results. A recent study identified not considering the amount of maternal smoking and age of onset as potentially masking a true association. We examine these issues and also the amount of maternal smoking during pregnancy as a determinant of the severity of depressive symptoms.

METHODS

We analyzed data from the community-based National Longitudinal Survey of Youth (US, 1994-2016). Mothers reported smoking during pregnancy (none, <1 pack/day, ≥1 pack/day). We assessed offspring's lifetime depression (i.e., ≥8 symptoms) and symptom counts with the Centers for Epidemiologic Studies Depression scale. We estimated the risk of these two outcomes in the full sample (n = 7172) and among siblings (n = 6145) using generalized linear mixed-effects models with random intercepts by family and family-averaged means for sibling analyses.

RESULTS

Among siblings, we observed dose-dependent elevations for both risk of depression (smoking during pregnancy <1 pack/day adjusted risk ratio [aRR] = 1.18; 95% confidence interval [CI] = 1.07, 1.30; smoking ≥1 aRR = 1.36; 95% CI = 1.19, 1.56) and severity of depressive symptoms (smoking <1 pack/day aRR = 1.12; 95% CI = 1.08, 1.16); smoking ≥1 pack/day aRR = 1.25; 95% CI = 1.18, 1.31). Among both samples, the P for trend was <0.01. In analysis limited to offspring diagnosed before age 18, results for severity were attenuated.

CONCLUSIONS

This evidence supports the existence of an independent association between maternal smoking during pregnancy and both the risk of depression and the severity of depressive symptoms. The results highlight the utility of considering the amount of smoking, severity of symptoms, and age of onset.

Maternal nicotine exposure promotes hippocampal CeRNA-mediated excitotoxicity and social barriers in adolescent offspring mice

Nicotine, an addictive component of cigarettes, causes cognitive defects, particularly when exposure occurs early in life. However, the exact mechanism through which nicotine causes toxicity and alters synaptic plasticity is still not fully understood. The aim of the current study is to examine how non-coding developmental regulatory RNA impacts the hippocampus of mice offspring whose mothers were exposed to nicotine. Female C57BL/6J mice were given nicotine water from one week before pregnancy until end of lactation. Hippocampal tissue from offspring at 20 days post-birth was used for LncRNA and mRNA microarray analysis. Differential expression of LncRNAs and mRNAs associated with neuronal development were screened and validated, and the CeRNA pathway mediating neuronal synaptic plasticity GM13530/miR-7119-3p/mef2c was predicted using LncBase Predicted v.2. Using protein immunoblotting, Golgi staining and behavioral tests, our findings revealed that nicotine exposure in offspring mice increased hippocampal NMDAR receptor, activated receptor-dependent calcium channels, enhanced the formation of NMDAR/nNOS/PSD95 ternary complexes, increased NO synthesis, mediated p38 activation, induced neuronal excitability toxicity. Furthermore, an epigenetic CeRNA regulatory mechanism was identified, which suppresses Mef2c-mediated synaptic plasticity and leads to modifications in the learning and social behavior of the offspring during adolescence. This study uncovers the way in which maternal nicotine exposure results in neurotoxicity in offspring.

Early developmental risks for tobacco addiction: A probabilistic epigenesis framework

Considerable progress has been made in elucidating the relationships between early life psychobiological and environmental risk factors and the development of tobacco addiction. However, a comprehensive understanding of the heterogeneity in tobacco addiction phenotypes requires integrating research findings. The probabilistic epigenesis meta-theory offers a valuable framework for this integration, considering systemic, multilevel, developmental, and evolutionary perspectives. In this paper, we critically review relevant research on early developmental risks associated with tobacco addiction and highlight the integrative heuristic value of the probabilistic epigenesis framework for this research. For this, we propose a four-level systems approach as an initial step towards integration, analyzing complex interactions among different levels of influence. Additionally, we explore a coaction approach to examine key interactions between early risk factors. Moreover, we introduce developmental pathways to understand interindividual differences in tobacco addiction risk during development. This integrative approach holds promise for advancing our understanding of tobacco addiction etiology and informing potentially effective intervention strategies.

Traumatic brain injury during pregnancy is associated with increased rate of cesarean section: a nationwide multi-register study in Finland

OBJECTIVE

The literature on the incidence of traumatic brain injury (TBI) during pregnancy is lacking. Furthermore, only studies with small sample size have analyzed the impact of TBI during pregnancy to maternal and fetal outcomes. Thus, we aim to report the incidence of TBIs during pregnancy and study the pregnancy outcomes using nationwide high-quality registers.

METHODS

This nationwide retrospective register-based matched cohort study utilized two national registers. All fertile-aged (15-49 years) women with a TBI hospitalization period during pregnancy were retrieved the Care Register for Health Care. Data were then linked with the data from the National Medical Birth Register (MBR). Propensity score matching was conducted according to maternal age during pregnancy, previous cesarean section (CS), maternal smoking status, maternal body mass index, and maternal gestational diabetes. The matching was conducted using the nearest neighbor methods with a caliber width if 0.15, and with a ratio 1:3 (patients/references). Adverse maternal and fetal outcomes were compared between patient group and reference group using Chi-squared tests.

RESULTS

A total of 392 women having a TBI during pregnancy were found. The control group consisted of 722,497 women without TBI during pregnancy. Of the TBIs occurring during pregnancy, the most common types of TBIs were concussion (S06.0) (n = 359, 91.6%), diffuse traumatic brain injury (S06.2) (n = 11, 2.8%), traumatic subdural hemorrhage (n = 7, 1.8%), and unspecified intracranial injury S06.9 (n = 6, 1.5%). The incidence rates of pregnancies with a TBI have remained similar during pregnancy in Finland, peaking at 0.8 per 1000 pregnancies in 2016. The Chi-squared test showed higher rate for CS among women with TBI than for their matched references (21.4% vs. 15.5%, p = .008). Especially, women with TBI during 3rd trimester had higher rate for CS (29.0 vs. 15.0%, p = .016).

CONCLUSIONS

The main findings of this study were that the incidence rates for TBI during pregnancy have remained similar during our study period (2004-2018). TBI during pregnancy, even a mild one, is associated with an increased rate for CS. Especially, TBI during the 3rd trimester was associated with high rate for CS, but the etiology behind this remains unknown. In addition, we found no evidence of difference in fetal outcomes, such as preterm birth, low birth weight, or need for intensive care unit. Future studies should focus on the indications for elective CS, and reasons for unplanned CS among women with TBI during pregnancy, as these could possibly provide important information on the effects of TBI on the course of childbirth.

Delivery mode and fetal outcome in attempted vaginal deliveries after previous cesarean section: a nationwide register-based cohort study in Finland

PURPOSE

Even though the risks and advantages of repeat Cesarean sections (CSs) and vaginal births after cesarean section (VBACs) are well studied, there is a scarcity of information on the effects of previous CS on maternal and fetal outcomes during subsequent deliveries. The aim of this study is to evaluate delivery mode and fetal outcomes in a trial of labor after cesarean section (TOLAC).

METHODS

In this nationwide retrospective cohort study, data from the National Medical Birth Register (MBR) were used to evaluate the outcomes of TOLACs. TOLACs were compared to the outcomes of the trial of labor after previous successful vaginal delivery. A multivariable logistic regression model was used to assess the primary outcomes (delivery mode, neonatal intensive care unit, and perinatal/neonatal mortality). Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were used for comparison.

RESULTS

A total of 29 352 (77.0%) women attempted vaginal delivery in the TOLAC group. In the control group, 169 377 (97.2%) women attempted vaginal delivery. The adjusted odds for urgent CS (aOR 13.05, CI 12.59-13.65) and emergency CS (aOR 3.65, CI 3.26-4.08) were notably higher in the TOLAC group when compared to the control group. The odds for neonatal intensive care unit treatment (aOR 2.05, CI 1.98-2.14), perinatal mortality (aOR 2.15, CI 1.79-2.57), and neonatal mortality (aOR 1.75, CI 1.20-2.49) were higher in the TOLAC group.

CONCLUSIONS

The odds for emergency CS were higher among women who underwent TOLAC. The odds for neonatal intensive care and perinatal mortality were also higher, and further research is needed to identify those expecting women who are better suited for TOLAC to minimize the risk for a neonate. The results of this study should be acknowledged by the mother and the clinician when considering the possibility of vaginal births after cesarean section.

A novel approach to risk exposure and epigenetics-the use of multidimensional context to gain insights into the early origins of cardiometabolic and neurocognitive health

BACKGROUND

Each mother-child dyad represents a unique combination of genetic and environmental factors. This constellation of variables impacts the expression of countless genes. Numerous studies have uncovered changes in DNA methylation (DNAm), a form of epigenetic regulation, in offspring related to maternal risk factors. How these changes work together to link maternal-child risks to childhood cardiometabolic and neurocognitive traits remains unknown. This question is a key research priority as such traits predispose to future non-communicable diseases (NCDs). We propose viewing risk and the genome through a multidimensional lens to identify common DNAm patterns shared among diverse risk profiles.

METHODS

We identified multifactorial Maternal Risk Profiles (MRPs) generated from population-based data (n = 15,454, Avon Longitudinal Study of Parents and Children (ALSPAC)). Using cord blood HumanMethylation450 BeadChip data, we identified genome-wide patterns of DNAm that co-vary with these MRPs. We tested the prospective relation of these DNAm patterns (n = 914) to future outcomes using decision tree analysis. We then tested the reproducibility of these patterns in (1) DNAm data at age 7 and 17 years within the same cohort (n = 973 and 974, respectively) and (2) cord DNAm in an independent cohort, the Generation R Study (n = 686).

RESULTS

We identified twenty MRP-related DNAm patterns at birth in ALSPAC. Four were prospectively related to cardiometabolic and/or neurocognitive childhood outcomes. These patterns were replicated in DNAm data from blood collected at later ages. Three of these patterns were externally validated in cord DNAm data in Generation R. Compared to previous literature, DNAm patterns exhibited novel spatial distribution across the genome that intersects with chromatin functional and tissue-specific signatures.

CONCLUSIONS

To our knowledge, we are the first to leverage multifactorial population-wide data to detect patterns of variability in DNAm. This context-based approach decreases biases stemming from overreliance on specific samples or variables. We discovered molecular patterns demonstrating prospective and replicable relations to complex traits. Moreover, results suggest that patterns harbour a genome-wide organisation specific to chromatin regulation and target tissues. These preliminary findings warrant further investigation to better reflect the reality of human context in molecular studies of NCDs.

The association between epidural labor analgesia and the fetal outcome and mode of delivery of the second twin: a nationwide register-based cohort study in Finland

BACKGROUND

The aim of this study was to assess the association between epidural labor analgesia and the mode of delivery for the second twin and to analyze the health outcomes of the second twin.

METHODS

In this nationwide, retrospective, register-based cohort study, data from the National Medical Birth Register (MBR) of Finland (2004-2018) were used to analyze the association between epidural analgesia and delivery mode (emergency and urgent cesarean section, and assisted vaginal delivery) and fetal outcomes (neonatal mortality and need for intensive care unit admission) for the second twin. Multivariable logistic regression was used to assess the delivery mode and fetal outcomes of the second twin.

RESULTS

A total of 3242 twin pregnancies with epidural analgesia were compared with a control group consisting of 2780 twin pregnancies without epidural analgesia. Epidural analgesia was associated with lower odds for all cesarean delivery (aOR 0.64, 95% CI 0.44 to 0.92) for the second twin and for emergency cesarean delivery (aOR 0.52, 95% CI 0.33 to 0.79) when compared with the odds for the second twin in the control group. Epidural analgesia was associated with lower odds of neonatal mortality for the second twin (aOR 0.61, 95% CI 0.73 to 0.90).

CONCLUSION

This study found epidural labor analgesia was associated with a lower rate of emergency cesarean delivery and neonatal mortality for the second twin. These results should be acknowledged by obstetricians and anesthesiologists when planning optimal peripartum management for mothers with twin pregnancies.

Latent Class Analysis of Prenatal Substance Exposure and Child Behavioral Outcomes

OBJECTIVES

To predict behavioral disruptions in middle childhood, we identified latent classes of prenatal substance use.

STUDY DESIGN

As part of the Environmental influences on Child Health Outcomes Program, we harmonized prenatal substance use data and child behavior outcomes from 2195 women and their 6- to 11-year-old children across 10 cohorts in the US and used latent class-adjusted regression models to predict parent-rated child behavior.

RESULTS

Three latent classes fit the data: low use (90.5%; n = 1986), primarily using no substances; licit use (6.6%; n = 145), mainly using nicotine with a moderate likelihood of using alcohol and marijuana; and illicit use (2.9%; n = 64), predominantly using illicit substances along with a moderate likelihood of using licit substances. Children exposed to primarily licit substances in utero had greater levels of externalizing behavior than children exposed to low or no substances (P = .001, d = .64). Children exposed to illicit substances in utero showed small but significant elevations in internalizing behavior than children exposed to low or no substances (P < .001, d = .16).

CONCLUSIONS

The differences in prenatal polysubstance use may increase risk for specific childhood problem behaviors; however, child outcomes appeared comparably adverse for both licit and illicit polysubstance exposure. We highlight the need for similar multicohort, large-scale studies to examine childhood outcomes based on prenatal substance use profiles.

Nicotine and Cytisine Embryotoxicity in the Experimental Zebrafish Model

Tobacco smoking is one of the most serious health problems. Potentially lethal effects of nicotine for adults can occur with as little as 30 to 60 mg, although severe symptoms can arise with lower doses. Furthermore, the route of administration also influences the toxicity. Cytisine is one of the most popular medications in nicotinism treatment. Like nicotine, cytisine is a plant alkaloid, signaling through nicotinic acetylcholine receptors. Our study evaluated the effects of cytisine in nicotine-induced embryotoxic effects using zebrafish larvae. We examined the teratogenicity of nicotine and cytisine alone or in combination. Nicotine increased mortality and delayed hatching of zebrafish larvae in a dose-dependent manner. Cytisine did not affect mortality in a wide range of concentrations, and hatching delay was observed only at the highest concentrations, above 2 mM. Administering compounds together partially reduced the adverse teratogenic effect induced by nicotine alone. The protective effect of cytisine against the nicotine effect, observed in zebrafish, will contribute to future studies or treatments related to nicotine addiction or prenatal nicotine exposure in humans.

Prenatal and Childhood Smoke Exposure Associations with Cognition, Language, and Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To assess the relationships of prenatal and childhood smoke exposure with specific neurodevelopmental and behavioral problems during early childhood.

STUDY DESIGN

A subsample (n = 386) of mother-child dyads from the Newborn Epigenetic Study (NEST) prebirth cohort participated in the study. Cotinine concentrations were used to objectively measure prenatal and childhood smoke exposure when youth were aged 3-13 years. Multivariable regression models were used to estimate associations of prenatal and childhood cotinine concentrations with performance on the National Institutes of Health (NIH) Toolbox and attention-deficit/hyperactivity disorder and behavioral symptoms, measured using the Behavior Assessment System for Children, 2nd edition (BASC-2).

RESULTS

After adjusting for confounders, childhood cotinine concentrations were associated with poorer cognitive performance on tasks measuring cognitive flexibility (B = -1.29; P = .03), episodic memory (B = -0.97; P = .02), receptive language development (B = -0.58; P = .01), and inhibitory control and attention (B = -1.59; P = .006). Although childhood cotinine concentration was associated with higher levels of attention problems (B = 0.83; P = .004) on the BASC-2, after adjustment for confounders, the association is nonsignificant. Although associations for maternal cotinine concentrations were null, an interaction was detected between prenatal and childhood cotinine concentrations on the NIH Toolbox Picture Vocabulary Task (P = .02).

CONCLUSIONS

Our findings suggest that childhood tobacco smoke exposure may lead to poorer attention regulation and language acquisition, complex visual processing ability, and attention problems.

Maternal smoking during pregnancy, offspring smoking, adverse childhood events, and risk of major depression: a sibling design study

BACKGROUND

Evidence of a biologically plausible association between maternal smoking during pregnancy (MSP) and the risk of depression is discounted by null findings from two sibling studies. However, valid causal inference from sibling studies is subject to challenges inherent to human studies of MSP and biases particular to this design. We addressed these challenges in the first sibling study of MSP and depression conducted among adults past the peak age for the onset of depression, utilizing a prospectively collected and biologically validated measure of MSP and accounting for non-shared as well as mediating factors.

METHODS

We fit GEE binomial regression models to correct for dependence in the risk of depression across pregnancies of the same mother. We also fit marginal structural models (MSM) to estimate the controlled direct effect of MSP on depression that is not mediated by the offspring's smoking status. Both models allow the estimation of within- and between-sibling risk ratios.

RESULTS

The adjusted within-sibling risk ratios (RR_W) from both models (GEE: RR_W = 1.97, CI 1.16-3.32; MSM: RR_W = 2.08, CI 1.04-4.17) evinced an independent association between MSP and risk of depression. The overall effects from a standard model evinced lower associations (GEE: RR_T = 1.12, CI 0.98-1.28; MSM: RR_T = 1.18, CI 1.01-1.37).

CONCLUSIONS

Based on within-sibling information free of unmeasured shared confounders and accounting for a range of unshared factors, we found an effect of MSP on the offspring's risk of depression. Our findings, should they be replicated in future studies, highlight the importance of considering challenges inherent to human studies of MSP and affective disorders.

New insights into smoking and urinary tract infections during pregnancy using pregnancy-pair design: A population-based register study

INTRODUCTION

Pregnancy itself predisposes to urinary tract infections (UTI). There appears to be a higher prevalence of infections and genitourinary diseases among pregnant smokers than among non-smokers. The present study is a retrospective observational register study aiming to investigate whether maternal smoking is associated with the prevalence of UTIs during pregnancy by utilizing a pregnancy-pair analysis.

MATERIAL AND METHODS

Information about pregnancies and maternal smoking was obtained from the Finnish Medical Birth Register. The study sample consisted of all singleton pregnancies (n = 723 433) of women giving birth between January 2006 and December 2018 in Finland. Information on maternal smoking was collected in three categories: (1) non-smoking; (2) quit smoking during the first trimester; and (3) continued smoking throughout the pregnancy. Information about maternal UTI diagnoses during pregnancy was received from the Hospital Discharge Register and the Medical Birth Register. UTIs were categorized as lower and upper UTIs according to the International Statistical Classification of Diseases and Related Health Problems (ICD)-10 diagnosis codes. Risks were calculated as odds ratios (OR) by logistic regression with 95% confidence intervals (CI) further adjusted for maternal characteristics (aOR). Finally, pregnancy-pair analyses were performed: mothers who had changed smoking status (no smoking/any smoking) between consecutive pregnancies (n = 27 246 pregnancy-pairs) were analyzed as one cluster and compared with non-smokers.

RESULTS

Smokers had UTIs more often compared with the non-smokers. The association was even stronger among those who continued to smoke (aOR 1.60, 95% CI 1.51-1.70) than among those who smoked only during the first trimester (aOR 1.27, 95% CI 1.18-1.37) compared with non-smokers. In pregnancy-pair analysis, smoking was associated with upper UTIs during pregnancy (OR 1.49, 95% CI 1.05-2.12) compared with non-smokers, but after the adjustments this association was attenuated (aOR 1.27, 95% CI 0.88-1.82). No association in lower UTIs was observed in the pregnancy-pair design.

CONCLUSIONS

Maternal smoking was associated with a higher prevalence of UTIs during pregnancy in the standard comparison. The observed association was fully attenuated in the pregnancy-pair analysis, in which smoking was dichotomized. This study suggests that the association between maternal smoking during pregnancy and adverse maternal health effects might be more complex than previously thought.

The roles of familial transmission and smoking during pregnancy on executive function skills: A sibling-comparison study

This research examines maternal smoking during pregnancy and risk for poorer executive function in siblings discordant for exposure. Data (N = 173 families) were drawn from the Missouri Mothers and Their Children study, a sample, identified using birth records (years 1998-2005), in which mothers changed smoking behavior between two pregnancies (Child 1 [older sibling]: M age = 12.99; Child 2 [younger sibling]: M age = 10.19). A sibling comparison approach was used, providing a robust test for the association between maternal smoking during pregnancy and different aspects of executive function in early-mid adolescence. Results suggested within-family (i.e., potentially causal) associations between maternal smoking during pregnancy and one working memory task (visual working memory) and one response inhibition task (color-word interference), with increased exposure associated with decreased performance. Maternal smoking during pregnancy was not associated with stop-signal reaction time, cognitive flexibility/set-shifting, or auditory working memory. Initial within-family associations between maternal smoking during pregnancy and visual working memory as well as color-word interference were fully attenuated in a model including child and familial covariates. These findings indicate that exposure to maternal smoking during pregnancy may be associated with poorer performance on some, but not all skills assessed; however, familial transmission of risk for low executive function appears more important.

Association of Maternal Tobacco Use During Pregnancy With Preadolescent Brain Morphology Among Offspring

IMPORTANCE

Maternal tobacco use during pregnancy has been associated with various health consequences, including suboptimal neurodevelopment in offspring. However, the effect of prenatal exposure to maternal smoking on child brain development has yet to be elucidated.

OBJECTIVE

To investigate the association between maternal smoking during pregnancy and offspring brain development in preadolescence as well as the mediating pathways.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, population-based cohort study was embedded in the Generation R Study, Rotterdam, the Netherlands. The Generation R Study was launched in 2002, with follow-up ongoing. Child brain morphology was assessed at 9 to 11 years of age (ie, 10-12 years between exposure and outcome assessment). Data analysis was performed from March 1, 2021, to February 28, 2022, and at the time of manuscript revision. Participants included the singleton children of pregnant women residing in the study area with an expected date of delivery between April 1, 2002, and January 31, 2006; 2704 children with information on maternal smoking during pregnancy and structural neuroimaging at 9 to 11 years of age were included. A subsample of 784 children with data on DNA methylation at birth was examined in the mediation analysis.

EXPOSURES

Information on maternal smoking during pregnancy was collected via a questionnaire in each trimester. As a contrast, paternal smoking was assessed at recruitment.

MAIN OUTCOMES AND MEASURES

Brain morphology, including brain volumes and surface-based cortical measures (thickness, surface area, and gyrification), was assessed with magnetic resonance imaging. For mediation analysis, DNA methylation at birth was quantified by a weighted methylation risk score.

RESULTS

The 2704 participating children (1370 [50.7%] girls and 1334 [49.3%] boys) underwent brain imaging assessment at a mean (SD) age of 10.1 (0.6) years. Compared with nonexposed children (n = 2102), exposure to continued maternal smoking during pregnancy (n = 364) was associated with smaller total brain volume (volumetric difference [b] = -14.5 [95% CI, -25.1 to -4.0] cm3), cerebral gray matter volume (b = -7.8 [95% CI, -13.4 to -2.3] cm3), cerebral white matter volume (b = -5.9 [95% CI, -10.7 to -1.0] cm3), and surface area and less gyrification. These associations were not explained by paternal smoking nor mediated by smoking-associated DNA methylation patterns at birth. Children exposed to maternal smoking only in the first trimester (n = 238) showed no differences in brain morphology compared with nonexposed children.

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that continued maternal tobacco use during pregnancy was associated with lower brain volumes and suboptimal cortical traits of offspring in preadolescence, which seemed to be independent of shared family factors. Tobacco cessation before pregnancy, or as soon as pregnancy is known, should be recommended to women for optimal brain development of their offspring.

Patterns of adverse childhood experiences and associations with prenatal substance use and poor infant outcomes in a multi-country cohort of mothers: a latent class analysis

BACKGROUND

This paper enumerates and characterizes latent classes of adverse childhood experiences and investigates how they relate to prenatal substance use (i.e., smoking, alcohol, and other drugs) and poor infant outcomes (i.e., infant prematurity and low birthweight) across eight low- and middle-income countries (LMICs).

METHODS

A total of 1189 mother-infant dyads from the Evidence for Better Lives Study cohort were recruited. Latent class analysis using the Bolck, Croon, and Hagenaars (BCH) 3-step method with auxiliary multilevel logistic regressions was performed.

RESULTS

Three high-risk classes and one low-risk class emerged: (1) highly maltreated (7%, n = 89), (2) emotionally and physically abused with intra-familial violence exposure (13%, n = 152), (3), emotionally abused (40%, n = 474), and (4) low household dysfunction and abuse (40%, n = 474). Pairwise comparisons between classes indicate higher probabilities of prenatal drug use in the highly maltreated and emotionally abused classes compared with the low household dysfunction and abuse class. Additionally, the emotionally and physically abused with intra-familial violence exposure class had higher probability of low birthweight than the three remaining classes.

CONCLUSION

Our results highlight the multifaceted nature of ACEs and underline the potential importance of exposure to childhood adversities on behaviors and outcomes in the perinatal period. This can inform the design of antenatal support to better address these challenges.

Maternal smoking during pregnancy and offspring psychiatric disorder: a longitudinal birth cohort study

BACKGROUND

There is evidence that prenatal stress and smoking during pregnancy both independently increase the risk of offspring psychopathology. Here we examine whether increased levels of self-reported stress is associated with increased smoking in a population of pregnant women, and whether prenatal smoking is associated with offspring psychiatric diagnoses independent of prenatal stress exposure.

METHOD

Using a longitudinal birth cohort, we used ordered logistic regressions to examine associations between maternal stress and smoking during pregnancy. We then used logistic regression analyses to examine associations between prenatal smoking and later offspring psychiatric disorders.

RESULTS

A dose-response relationship was found between maternally reported stress and smoking during pregnancy. Pregnant women reporting severe stress were more likely to smoke compared to both the moderate stress and no stress groups, and those reporting moderate stress were significantly more likely to smoke compared to the no stress group. Smoking more than 5 cigarettes daily during pregnancy increased the risk of offspring personality disorder (OR 3.08, 95% CI 1.60-5.94) as well as developing any Axis 1 psychiatric disorder, inclusive of mood, anxiety and psychotic disorders (OR 1.45, 95% CI 1.04-2.04). After adjusting for parental psychiatric history and maternal self-reported stress during pregnancy, associations between smoking more than 5 cigarettes daily when pregnancy and offspring personality (OR 2.58 95% CI 1.32-5.06) disorder remained.

CONCLUSION

Exposure to cigarette smoking during gestation could impact a child's mental health. Smoking during pregnancy is a prime target for preventative interventions as unlike most other environmental risk factors, it is very amenable to change.

Can prenatal methamphetamine exposure be considered a good animal model for ADHD?

Attention-deficit/hyperactivity disorder (ADHD) is a mental disorder with a heterogeneous origin with a global incidence that continues to grow. Its causes and pathophysiological mechanisms are not fully understood. It includes a combination of persistent symptoms such as difficulty in concentration, hyperactivity and impulsive behavior. Maternal methamphetamine (MA) abuse is a serious problem worldwide, it can lead to behavioral changes in their offspring that have similarities with behavioral changes seen in children with ADHD. There are several types of ADHD animal models, e.g. genetic models, pharmacologically, chemically and exogenously induced models. One of the exogenously induced ADHD models is the hypoxia-induced model. Our studies, as well as those of others, have demonstrated that maternal MA exposure can lead to abnormalities in the placenta and umbilical cord that result in prenatal hypoxia as well as fetal malnutrition that can result in irreversible changes to experimental animals. Therefore, the aim the present study was to compare the cognitive impairments in MA exposure model with those in established model of ADHD - prenatal hypoxia model, to test whether MA exposure is a valid model of ADHD. Pregnant Wistar rats were divided into four groups based on their gestational exposure to MA: (1) daily subcutaneous injections of MA (5 mg/kg), (2) saline injections at the same time and volume, (3) daily 1-hr hypoxia (10 % O2), and (4) no gestational exposure (controls). Male rat offspring were tested for short-term memory in the Novel Object Recognition Test and the Object Location Test between postnatal days 35 and 40. Also their locomotor activity in both tests was measured. Based on the present results, it seems that prenatal MA exposure is not the best animal model for ADHD since it shows corresponding symptoms only in certain measures. Given our previous results supporting our hypothesis, more experiments are needed to further test possible use of prenatal MA exposure as an animal model of the ADHD.

Smoking status: A tacit screen for postpartum depression in primary care settings

BACKGROUND

Universal screening for postpartum depression (PPD) remains an unachieved national priority. A tacit screen that requires no additional resources for administration can help to achieve this priority. We examine the predictive utility of using smoking as a tacit screen for PDD. We first establish smoking is a valid proxy for more prominent psychosocial determinants of PPD and is a predictor for PPD.

METHODS

We analyzed PRAMS data (2012-2015; N=134,435). Time of smoking was categorized as nonsmoker, during the prenatal period, the postpartum, or continuously; PPD was assessed using two PHQ-2 style questions.

RESULTS

Compared to nonsmokers, women who smoked only during the prenatal period (OR: 1.41; 95% CI: 1.06 - 1.86), only during the postpartum (OR: 1.33; 95% CI: 1.18 - 1.49), and continuously throughout both periods (OR: 1.54; 95% CI: 1.41 - 1.69) were more likely to experience PPD. Smoking assessed at a prenatal visit (SN: 0.90, SP: 0.21), postpartum visit (SN: 0.86, SP: 0.25), or assessed at both visits (SN: 0.90, SP: 0.19) performed relatively well as a tacit screen for PPD, performing better among unmarried women (SN: 0.75 - 0.81; SP: 0.29 - 0.36).

LIMITATIONS

In this study, the criterion of positivity used was PRAMS' adapted version of the PHQ-2. This tacit screen may perform differently relative to a clinical diagnosis.

CONCLUSIONS

Time of smoking predicts risk of PPD and can be used to tacitly screen for PPD with reasonable accuracy without requiring any additional time in settings with limited resources for routine screening of PPD.

Maternal smoking during pregnancy and poor academic performance in adolescent offspring: A registry data-based cohort study

BACKGROUND

Previous studies have suggested associations between maternal smoking during pregnancy (MSDP) and a range of adverse outcomes in offspring. However, evidence reporting adverse effects on poor academic performance in adolescence is scant.

METHODS

This register-based cohort study used linked data obtained from New South Wales (NSW) educational and health registries in Australia. MSDP was assessed using self-reports of smoking during pregnancy. Offspring's educational performance was assessed using the National Assessment Program for Literacy and numeracy (NAPLAN), when students were in grade 9 and approximately aged 14 years. We used multivariable logistic regression models to explore associations.

RESULTS

Adolescent offspring exposed to MSDP were at an increased risk of substandard academic performance in all domains, with the highest odds for spelling [OR, 3.12 (95%CI 2.98-3.26)] followed by writing [OR, 2.97 (95%CI 2.84-3.11)], reading [OR, 2.49 (95%CI 2.37-2.62)], and numeracy [OR, 2.43 (95%CI 2.30-2.58)]. In our sex-stratified analysis, MSDP displayed stronger effects on the academic performance of female offspring in all domains.

CONCLUSIONS

Our findings showed that MSDP was associated with an increased risk of reduced academic performance in adolescent offspring. The different effects of MSDP on the academic performance of male and female offspring is a new finding, which needs further investigation.

Impact of prenatal exposure characterization on early risk detection: Methodologic insights for the HEALthy Brain and Child Development (HBCD) study

BACKGROUND

A major challenge in prenatal drug exposure research concerns the balance of measurement quality with sample sizes necessary to address confounders. To inform the selection of optimal exposure measures for the HEALthy Brain and Child Development (HBCD) Study, we employed integrated analysis to determine how different methods used to characterize prenatal tobacco exposure influence the detection of exposure-related risk, as reflected in normal variations in birth weight.

METHODS

Participants were N = 2323 mother-infant dyads derived from 7 independent developmental cohorts harmonized on measures of exposure, outcome (birthweight), and covariates. We compared estimates of PTE-related effects on birthweight derived from linear regression models when PTE was categorized dichotomously based on any fetal exposure (30% exposed; 69% not exposed); versus categorically, based on common patterns of maternal smoking during pregnancy (never smoked 69%; quit smoking 16%; smoked intermittently 2%; smoked persistently 13%). We secondarily explored sex differences in PTE-birthweight associations across these categorization methods.

RESULTS

When PTE was categorized dichotomously, exposure was associated with a - 125-g difference in birthweight (95% C.I. -173.7 - -76.6, p < .0001). When PTE was characterized categorically based on maternal smoking patterns, however, exposure was associated with either no difference in birthweight if mothers quit smoking by the end of the first trimester (B = -30.6, 95% C.I. -88.7-27.4, p = .30); or a - 221.8 g difference in birthweight if mothers did not [95% C.I. (-161.7 to -282.0); p < .001]. Qualitative sex differences were also detected though PTE x sex interactions did not reach statistical significance. Maternal smoking cessation during pregnancy was associated with a 239.3 g increase in birthweight for male infants, and a 114.0 g increase in birthweight for females infants (p = .07).

CONCLUSIONS

Categorization of PTE based on patterns of maternal smoking rather than the presence or absence of exposure alone revealed striking nuances in estimates of exposure-related risk. The described method that captures both between-individual and within-individual variability in prenatal drug exposure is optimal and recommended for future developmental investigations such as the HBCD Study.

Development of national dietary and lifestyle guidelines for pregnant women in Lebanon

Although a number of international diet and lifestyle guidelines during pregnancy (DLGP) exist in the literature, contextualization to low- and middle-income settings is less common. The aim of this study was to present the Lebanese DLGP and to describe the process followed for their development. A mixed-method approach was used including a review and synthesis of existing international DLGP and a consensus building nominal group technique (NGT) with a multidisciplinary group of experts (n = 11). During the meeting, participants identified the themes of the guidelines, formulated the wording of each themes' guideline and translated the guidelines to the Arabic language. Consensus was defined as an agreement of 80%. Reviewing the literature, a list of 17 main topics were found to be common themes for the DLGP. For the Lebanese DLGP, participants in the NGT meeting selected seven themes from this list: gestational weight gain, diet diversity, hydration, food safety, harmful foods, physical activity and breastfeeding. In addition, the group formulated three themes based on merging/modifying existing themes: supplementation, alcohol and smoking and religious fasting. Two context-specific new themes emerged: wellbeing and nutrition resilience. For each of the identified themes, the group agreed upon the wording of its guidelines and description. This study is the first from the Eastern Mediterranean Region to develop through consensus building, context and culture-specific dietary and lifestyle guidelines for pregnant women. Putting maternal nutrition at the heart of tackling malnutrition and its detrimental health outcomes is a core investment for a better maternal and child health.

Decreased head circumference at birth associated with maternal tobacco smoke exposure during pregnancy on the Japanese prospective birth cohort study

Maternal tobacco smoke exposure during pregnancy impairs fetal body size, including head circumference (HC) at birth; however, the mechanism still remains unclear. This analysis using a large prospective cohort study evaluated the impact of maternal tobacco exposure on their offspring's HC and the relationship with placental weight ratio (PWR) and placental abnormalities. Parents-children pairs (n = 84,856) were included from the 104,065 records of the Japan Environmental and Children's Study. Maternal perinatal clinical and social information by self-administered questionnaires, offspring's body size, and placental information were collected. Data were analyzed with binominal logistic regression analysis and path analysis. Logistic regression showed significantly elevated adjusted odds ratio (aOR) (1.653, 95% CI 1.387-1.969) for the impact of maternal smoking during pregnancy on their offspring's smaller HC at birth. Maternal exposure to environmental tobacco smoke in the non-smoking group did not increase aOR for the smaller HC. Path analysis showed that maternal smoking during pregnancy decreased the offspring's HC directly, but not indirectly via PWR or placental abnormalities. The quitting smoking during pregnancy group did not increase aOR for the smaller HC than the non-smoking group, suggesting that quitting smoking may reduce their offspring's neurological impairment even after pregnancy.

DNA methylome perturbations: an epigenetic basis for the emergingly heritable neurodevelopmental abnormalities associated with maternal smoking and maternal nicotine exposure†

Maternal smoking during pregnancy is associated with an ensemble of neurodevelopmental consequences in children and therefore constitutes a pressing public health concern. Adding to this burden, contemporary epidemiological and especially animal model research suggests that grandmaternal smoking is similarly associated with neurodevelopmental abnormalities in grandchildren, indicative of intergenerational transmission of the neurodevelopmental impacts of maternal smoking. Probing the mechanistic bases of neurodevelopmental anomalies in the children of maternal smokers and the intergenerational transmission thereof, emerging research intimates that epigenetic changes, namely DNA methylome perturbations, are key factors. Altogether, these findings warrant future research to fully elucidate the etiology of neurodevelopmental impairments in the children and grandchildren of maternal smokers and underscore the clear potential thereof to benefit public health by informing the development and implementation of preventative measures, prophylactics, and treatments. To this end, the present review aims to encapsulate the burgeoning evidence linking maternal smoking to intergenerational epigenetic inheritance of neurodevelopmental abnormalities, to identify the strengths and weaknesses thereof, and to highlight areas of emphasis for future human and animal model research therein.

Mental disorders in referred 0-3-year-old children: a population-based study of incidence, comorbidity and perinatal risk factors

The epidemiology of mental disorders in early childhood is still under-researched. We aim to explore the incidence, comorbidities and risk factors of mental disorders in 0-3-year-olds referred to hospital settings. In a national cohort of 918,280 children born in 1997-2010, we calculated incidence rates per 1,000 person-years (IR) of first-time mental and developmental disorders diagnosed in hospitals before four years of age. Data were obtained from Danish population registries. We used logistic regression to analyse co-morbidity and Cox proportional hazard models to evaluate the influence of pre- and perinatal risk factors. A total of 16,164 children (1.76%) were diagnosed with a mental (0.90%) or developmental disorder (1.05%). Pervasive developmental disorders (PDD) and disorders of hyperactivity and inattention (ADHD) were increasingly diagnosed with age. Feeding and eating disorders and disorders of social functioning were most frequent among the youngest children. Comorbidity was found in 18%, e.g., between PDD and ADHD (OR 135.8; 95% CI 112.0-164.7) or between ADHD and disorders of social functioning (OR 148.0; 95% CI 106.4-205.7). Young maternal age, old paternal age, maternal smoking in pregnancy, boy sex, premature birth and being small for gestational age were associated with highly increased risk of mental and developmental disorders. Mental and developmental disorders diagnosed within the first four years of life show increasing incidence rates and a complex pattern of comorbidities. Study findings point to the need of clinical and research attention towards the manifestations of developmental psychopathology in very young children.

Does maternal exposure to nicotine affect the oocyte quality and reproductive capacity in adult offspring?

Gonadal development begins in the intrauterine phase and females from most species are born with an established oocyte reserve. Exposure to drugs during gestation can compromise the offspring health, also affecting the gametes quality. Nicotine, the main component of cigarettes, is an oxidant agent capable of altering the fertility in men and women. As female gametes are susceptible to oxidative stress, this drug can damage the oolemma and affect oocyte maturation, induce errors during chromosomal segregation and DNA fragmentation. Oocyte mitochondria are particularly susceptible to injuries, contributing to the oocyte quality loss and embryonic development disruption. Thus, considering the high number of women who smoke during pregnancy, while significant events are occurring in the embryo for future fertility of offspring, we seek to verify the quality of the oocytes from adult rats exposed to nicotine during intrauterine phase and breastfeeding. Pregnant Wistar rats received nicotine by osmotic mini-pumps and the female progenies were evaluated in adulthood for oocyte quality (viability, lipid peroxidation, generation of reactive oxygen species and mitochondrial integrity) and reproductive capacity. Embryos (3dpc) and fetuses (20dpc) generated by these rats were also evaluated. The results showed that the dose of 2 mg/kg/day of nicotine through placenta and breast milk does not affect the number of oocytes and the fertility capacity of adult rats. However, it causes some morphological alterations in oocytes, mitochondrial changes, embryonic fragmentation and disruption of fetal development. The malformations in fetuses generated from these gametes can also indicate the occurrence of epigenetic modifications.

ADHD symptomatology of children with congenital heart disease 10 years after cardiac surgery: the role of age at operation

BACKGROUND

The aim of the present study was to investigate the differences in ADHD symptomatology between healthy controls and children who underwent cardiac surgery at different ages.

METHODS

Altogether, 133 children (54 patients with congenital heart disease undergoing first cardiac surgery under 3 years of age, 26 operated at the age of 3 or later, and 53 healthy controls) were examined. Patients completed the Youth Self Report (YSR), while their parents completed the Child Behaviour Checklist (CBCL) and the ADHD Rating Scale-IV.

RESULTS

Children receiving surgery for the first time under the age of 3 years were more likely diagnosed with cyanotic type malformation and have undergone to a greater number of operations. However, ADHD symptoms of those treated surgically at or above 3 years of age were more severe than that of the control group or those who were treated surgically at a younger age. The control group and those treated surgically below the age of three did not differ across any of the ADHD symptom severity indicators.

CONCLUSIONS

The age at the time of cardiac surgery might be associated with later ADHD symptom severity - with lower age at operation associated with better outcomes. Further, adequately powered studies are needed to confirm these exploratory findings and investigate the moderators of this relationship.

The Intergenerational Transmission of Developmental Nicotine Exposure-Induced Neurodevelopmental Disorder-Like Phenotypes is Modulated by the Chrna5 D397N Polymorphism in Adolescent Mice

Maternal tobacco smoking during pregnancy constitutes developmental nicotine exposure (DNE) and is associated with nicotine dependence and neurodevelopmental disorders in both children and grandchildren as well as animal models thereof. Genetic variants such as the CHRNA5 single nucleotide polymorphism (SNP) rs16969968, which leads to an aspartic acid to asparagine substitution at amino acid position 398 (D398N) in the alpha-5 nicotinic acetylcholine receptor subunit, can also confer risk for nicotine dependence and neurodevelopmental disorders in the absence of DNE. However, the degrees to which, the consequences of maternal smoking on offspring outcomes are influenced by genetic variants and interactions therewith are not well understood. Addressing this void in the literature, the present study utilizes a DNE mouse model engineered to possess the equivalent of the human D398N SNP in CHRNA5 (D397N SNP in mice) to assess how the N397 risk allele impacts the induction and intergenerational transmission of a range of neurodevelopmental disorder-related behavioral phenotypes in first- and second-generation DNE offspring. Results reveal that offspring possessing the N397 variant in the absence of DNE as well as DNE offspring and grand offspring possessing theD397 variant exhibit analogous neurodevelopmental disorder-like phenotypes including hyperactivity, risk-taking behaviors, aberrant rhythmicity of activity, and enhanced nicotine consumption. DNE amplified these behavioral anomalies in first-generation N397 progeny, but the severity of DNE-evoked behavioral perturbations did not significantly differ between first-generation D397 and N397 DNE mice for any measure. Remarkably, the behavioral profiles of second-generation N397 DNE progeny closely resembled DNE-naive D397 mice, suggesting that the N397 variant may protect against the intergenerational transmission of DNE-induced neurodevelopmental disorder-like behaviors.

Maternal pregnancy diet, postnatal home environment and executive function and behavior in 3- to 4-y-olds

BACKGROUND

Optimal maternal nutrition during pregnancy has been linked to better cognitive and behavioral development in children. However, its influence on the effects of suboptimal postnatal exposures like reduced stimulation and support in the home is not known.

OBJECTIVES

To examine the effect of maternal pregnancy diet on executive function and/or behavioral development in children raised in suboptimal home environments.

METHODS

Data were provided by 808 mother-infant dyads from the Canadian Maternal-Infant Research on Environmental Chemicals-Child Development study. Maternal pregnancy diet was self-reported using the Healthy Eating Index 2010 questionnaire. Stimulation and support in the home was assessed using the Home Observation for Measurement of the Environment (HOME) when children were 3-4 y old. Child executive function was reported by mothers at this age using the Behavior Rating Inventory of Executive Functioning-Preschool Edition, and child behavior was assessed using the Behavior Assessment System for Children-2nd Edition. We examined the interaction of maternal pregnancy diet and postnatal HOME scores on child executive function and behavior using linear regression adjusted for maternal education, postpartum depression, prepregnancy BMI, and smoking.

RESULTS

Maternal pregnancy diet was associated with an increasingly positive association with child working memory (β: 0.21; 95% CI: 0.82, 3.41; P = 0.001), planning (β: 0.17; 95% CI: 0.38, 2.84; P = 0.007), and adaptability (β: -0.13; 95% CI: -1.72, -0.08; P = 0.032) as levels of postnatal stimulation decreased.

CONCLUSIONS

The positive association of maternal pregnancy diet quality and executive function and adaptability in 3- to 4-y-olds appeared to increase with decreasing levels of postnatal stimulation and support. These results suggest that overall maternal pregnancy diet could be linked to better child neurodevelopment in families experiencing barriers to providing stimulation and support to children in their home.

Design of a prospective follow-up study on early parenthood and smoking behaviour during pregnancy in Finnish primary healthcare

Aims: The primary aim of the study is to explore different factors affecting parents’ smoking behaviour, and especially how smoking may be connected with individual differences in the psychological process of becoming a parent. In the current paper, we present the study design together with basic information on the study population. Methods: The Central Satakunta Maternity and Child Health Clinic (KESALATU) Study is an ongoing prospective follow-up study in primary healthcare of the Satakunta region of southwest Finland. Families were recruited during their first maternity clinic visit between 1 September 2016 and 31 December 2019, and participation will continue until the child is 1.5 years of age. The study combines different sources and types of data: e.g. routine data obtained from primary healthcare clinic records, specific parental self-report data and data from a new exhaled carbon monoxide meter indicating maternal smoking. The data are collected using frequently repeated assessments both during pregnancy and postnatally. The methods cover the following areas of interest: family background factors (including smoking and alcohol use), self-reported parental–foetal/infant attachment and mentalization, self-reported stress, depression and quality of life. Results: 589 pregnant women and their partners were asked to participate in the study during the collection time period. The final study population consisted of 248 (42.1%) pregnant women and 160 (27.1%) partners. Conclusions: The new methods and study design have the potential to increase our understanding about the link between early parenting psychology, prenatal psychosocial risk factors and parental health behaviour.

Epigenetic Alterations of Maternal Tobacco Smoking during Pregnancy: A Narrative Review

In utero exposure to maternal tobacco smoking is the leading cause of birth complications in addition to being associated with later impairment in child’s development. Epigenetic alterations, such as DNA methylation (DNAm), miRNAs expression, and histone modifications, belong to possible underlying mechanisms linking maternal tobacco smoking during pregnancy and adverse birth outcomes and later child’s development. The aims of this review were to provide an update on (1) the main results of epidemiological studies on the impact of in utero exposure to maternal tobacco smoking on epigenetic mechanisms, and (2) the technical issues and methods used in such studies. In contrast with miRNA and histone modifications, DNAm has been the most extensively studied epigenetic mechanism with regard to in utero exposure to maternal tobacco smoking. Most studies relied on cord blood and children’s blood, but placenta is increasingly recognized as a powerful tool, especially for markers of pregnancy exposures. Some recent studies suggest reversibility in DNAm in certain genomic regions as well as memory of smoking exposure in DNAm in other regions, upon smoking cessation before or during pregnancy. Furthermore, reversibility could be more pronounced in miRNA expression compared to DNAm. Increasing evidence based on longitudinal data shows that maternal smoking-associated DNAm changes persist during childhood. In this review, we also discuss some issues related to cell heterogeneity as well as downstream statistical analyses used to relate maternal tobacco smoking during pregnancy and epigenetics. The epigenetic effects of maternal smoking during pregnancy have been among the most widely investigated in the epigenetic epidemiology field. However, there are still huge gaps to fill in, including on the impact on miRNA expression and histone modifications to get a better view of the whole epigenetic machinery. The consistency of maternal tobacco smoking effects across epigenetic marks and across tissues will also provide crucial information for future studies. Advancement in bioinformatic and biostatistics approaches is key to develop a comprehensive analysis of these biological systems.

Suicidal ideation and attempt in adolescents exposed to maternal smoking across pregnancy and childhood: A 20-year prospective cohort study

BACKGROUND

Few studies investigated the association between maternal smoking during pregnancy and offspring suicide risk, none considering postnatal smoking exposure. We investigated associations between maternal smoking patterns during the pre- and postnatal periods and adolescent suicidal ideation and attempt.

METHODS

We identified longitudinal patterns of maternal smoking from the prenatal period to the end of childhood (children's age 12 years, 10 assessments) among participants in the Québec Longitudinal Study of Child Development (N = 1623). We estimated associations between maternal smoking patterns and offspring self-reported suicidal ideation and attempt (ages 13-20). Background confounding factors (e.g., socioeconomic, familial, mental health) were controlled using propensity score inverse-probability weighting (IPW).

RESULTS

Participants reporting suicidal ideation and attempt were 9.3% and 8.4%, respectively. We identified four maternal smoking patterns: non-smoking (66.5%), increasing (5.5%), decreasing (9.3%), persistent (18.5%). Children exposed to persistent (OR=2.92, CI=1.99-4.30) and increasing (OR=2.06, CI=1.13-3.74) maternal smoking were more likely to attempt suicide, compared to non-exposed children. Accounting for confounding factors using IPW fully explained the association between increasing smoking and suicide attempt (OR=0.95, CI=0.39-2.09) but only reduced the association between persistent exposure and suicide attempt (OR=2.30, CI=1.04-4.99). No increased suicide attempt risk was found for children of mothers with a decreased smoking pattern. We found no associations for suicidal ideation.

LIMITATIONS

Propensity score cannot account for unmeasured confounding factors; attrition limits generalizability.

CONCLUSIONS

Offspring of mothers who smoked persistently and heavily prenatally and postnatally were at increased risk of suicide attempt in adolescence. Future studies should elucidate biological and psychosocial mechanisms potentially at play in these associations.

DNA methylation mediates the effect of maternal smoking on offspring birthweight: a birth cohort study of multi-ethnic US mother-newborn pairs

Background

Maternal smoking affects more than half a million pregnancies each year in the US and is known to result in fetal growth restriction as measured by lower birthweight and its associated long-term consequences. Maternal smoking also has been linked to altered fetal DNA methylation (DNAm). However, what remains largely unexplored is whether these DNAm alterations are merely markers of smoking exposure or if they also have implications for health outcomes. This study tested the hypothesis that fetal DNAm mediates the effect of maternal smoking on newborn birthweight.

Methods

This study included mother–newborn pairs from a US predominantly urban, low-income multi-ethnic birth cohort. DNAm in cord blood were determined using the Illumina Infinium MethylationEPIC BeadChip. After standard quality control and normalization procedures, an epigenome-wide association study (EWAS) of maternal smoking was performed using linear regression models, controlling for maternal age, education, race, parity, pre-pregnancy body mass index, alcohol consumption, gestational age, maternal pregestational/gestational diabetes, child sex, cord blood cell compositions and batch effects. To quantify the degree to which cord DNAm mediates the smoking-birthweight association, the VanderWeele-Vansteelandt approach for single mediator and structural equational model for multiple mediators were used, adjusting for pertinent covariates.

Results

The study included 954 mother–newborn pairs. Among mothers, 165 (17.3%) ever smoked before or during pregnancy. Newborns with smoking exposure had on average 258 g lower birthweight than newborns without exposure (P < 0.001). Using a false discovery rate (FDR) < 0.05 as the significance cutoff, the EWAS identified 38 differentially methylated CpG sites associated with maternal smoking. Of those, 17 CpG sites were mapped to previously reported genes: GFI1, AHRR, CYP1A1, and CNTNAP2; 8 of those, located in the first three genes, were Bonferroni significantly associated with newborn birthweight and mediated the smoking-birthweight association. The combined mediation effect of the three genes explained 67.8% of the smoking-birthweight association.

Conclusions

Our study not only lends further support that maternal smoking alters fetal DNAm in a multiethnic population, but also suggests that fetal DNAm substantially mediates the maternal smoking–birthweight association. Our findings, if further validated, indicate that DNAm modification is likely an important pathway by which maternal smoking impairs fetal growth and, perhaps, even long-term health outcomes.

Secondhand Smoke Exposure during Pregnancy and its Effect on Birth Outcomes: Evidence from a Retrospective Cohort Study in a Tertiary Care Hospital in Bengaluru

Context:

The effect of maternal smoking on birth outcomes is well-established, but the effect of maternal secondhand smoke (SHS) exposure is less clear, especially among Indian women.

Aim:

To evaluate the effect of SHS exposure during pregnancy on birth outcomes such as gestational age at birth, neonatal anthropometry, and Apgar score.

Setting and Design:

Retrospective cohort study at a tertiary hospital in Bengaluru.

Methods:

208 postnatal mothers: 104 each in “exposed” and “nonexposed” group, based on the history of SHS exposure during pregnancy. Sociodemographic and obstetric details were obtained by interview schedule and birth outcomes were obtained from patient charts.

Statistical Analysis:

Association of SHS exposure with birth outcomes was analyzed using inferential statistics such as Chi-square, t-test, and Mann–Whitney U-test, whereas the strength of association was expressed as relative risk with 95% confidence intervals. P < 0.05 was considered statistically significant.

Results:

SHS exposed and nonexposed groups were comparable with regard to potentially confounding socioeconomic and obstetric covariates. Babies born to SHS-exposed mothers had significantly lower mean birth weight, mean birth length, and mean birth head circumference by 172.5 g (P = 0.027), 1.6 cm (P = 0.001), and 1.1 cm (P = 0.001), respectively.

Conclusion:

Mothers exposed to SHS during pregnancy were twice likely to deliver low birth weight babies (relative risk [RR] = 1.9 [1.0–3.6], P = 0.02) and babies of low birth length (RR = 2.64 [1.4–4.6], P = 0.001) than unexposed mothers. With a significant risk of adverse birth outcomes found among mothers exposed to SHS during pregnancy, it is important that a “no tobacco smoke” environment at home should be recommended for pregnant women and their families.

A sibling-comparison study of smoking during pregnancy and risk for reading-related problems

This research examines the relationship between smoking during pregnancy (SDP) and risk for reading related problems in siblings discordant for exposure to SDP. Data (N = 173 families) were drawn from the Missouri Mothers and Their Children study, a sample, identified using birth records (years 1998-2005), in which mothers changed her smoking behavior between two pregnancies (Child 1 [older sibling]: M = 12.99; Child 2 [younger sibling]: M = 10.19). A sibling comparison approach was used, providing a robust test for the association between SDP and reading related outcomes in school-aged children. Results suggested within-family (i.e., potentially causal) associations between SDP and reading and language/comprehension factor scores, as well as between SDP and specific reading-related skills, including reading accuracy and receptive language, with increased exposure to SDP associated with decreased performance. SDP was not associated with spelling, reading rate, or receptive vocabulary. Initial within-family associations between SDP and word-letter identification, phonetic/decoding skills, and reading comprehension were fully attenuated following partial control for genetic and environmental confounding of the associations. These findings indicate that exposure to SDP is associated with poorer performance on some, but not all skills assessed.

Prenatal alcohol and tobacco use and the risk of depression in offspring at age of 17 years: findings from the Raine Study

BACKGROUND

Prenatal alcohol and tobacco exposures have been associated with adverse mental health consequences in offspring. The objective of this study was to test the associations between maternal prenatal alcohol and tobacco exposures and depressive symptoms in the offspring, adjusting for a wide range of potential confounders.

METHODS

We used data from 1168 mother-offspring pairs from the Raine Study based in Perth, Western Australia. Depressive symptoms at age 17 years were measured using the Beck Depression Inventory for Youth (BDI-Y). Associations between prenatal alcohol and tobacco use and the risk of depressive symptoms in offspring were estimated by risk ratios (RR) derived with multivariable log-binomial regression.

RESULTS

Among offspring who were assessed for depressive symptoms, 5% were born to mothers who consumed six or more standard drinks of alcohol per week during pregnancy and 20% were exposed to prenatal tobacco. After adjustment for confounders, depressive symptoms at the age of 17 years remained associated with maternal alcohol use of six or more standard drinks per week [RR 1.59 (95% CI: 1.11-2.26)] and any tobacco use [RR 1.36 (95% CI: 1.05-1.79)] during the first trimester of pregnancy.

CONCLUSION

Offspring exposed to prenatal alcohol and tobacco use had greater risks of depressive symptoms compared with unexposed offspring, suggesting early screening and prevention of these exposures could possibly reduce depressive symptoms in offspring.

The Influence of Oxidative Stress-Related Factors on Pregnancy and Neonatal Outcomes

Background: Pregnancy is a physiological process associated with an excessive oxidative stress for both the mother and the neonate. Oxidative stress was extensively studied and is still in focus as a factor of maternal pathologies during pregnancy, with consequences on the outcome of the neonate.

Aim: The aim of our study was to determine whether oxidative stress-related factors can influence the outcome of pregnancy, delivery, and the neonate’s wellbeing.

Material and methods: The study was conducted using a questionnaire among pregnant women with voluntary enrollment. Exclusion criteria were preeclampsia or other cardiovascular diseases, gestational diabetes, and hypothyroidism at admission. Patients were enrolled in a control group of 60 pregnant women without preexisting pathology and pregnancy with physiological course, a premature group of 21 pregnant women with premature delivery, and a cardiac group of 8 pregnant women with fetal heart disease known before birth. The study population was separated into subgroups based on dietary supplement use within the three main groups, and other subgroups for smoking/non-smoking mothers in the control group and one for smoking/non-smoking mothers in the premature and cardiac groups together.

Results: The mean Apgar score at 1 minute was significantly higher in the control group compared to the cardiac group (p = 0.0023). The 1-minute Apgar score was significantly lower in infants that were born premature, from smoking mothers, compared to babies that were delivered at term (p = 0.0191). Although we did not obtain significant differences in birth weight corrected by gestational age between the control (mature) group and premature group, there was a good correlation in gestational age and birth weight of the preterm born infants (r = 0.8517, p <0.0001).

Conclusions: Smoking can aggravate oxidative stress in pregnancy, which will contribute to a difficult postnatal adaptation of newborns from smoking mothers and will increase the risk of premature delivery.

Disruptive Behavior in Siblings Discordant for Exposure to Maternal Smoking During Pregnancy: A Multi-rater Approach

INTRODUCTION

Maternal smoking during pregnancy (SDP) is associated with disruptive behavior. However, there is debate whether the SDP-disruptive behavior association is a potentially causal pathway or rather a spurious effect confounded by shared genetic and environmental factors.

AIMS AND METHODS

The Missouri Mothers and Their Children Study is a sibling comparison study that includes families (n = 173) selected for sibling pairs (aged 7-16 years) discordant for SDP. Critically, the sibling comparison design is used to disentangle the effects of SDP from familial confounds on disruptive behavior. An SDP severity score was created for each child using a combination of SDP indicators (timing, duration, and amount of SDP). Multiple informants (parents and teachers) reported on disruptive behavior (i.e., DSM-IV semi-structured interview, the Child Behavior Checklist, and Teacher Report Form).

RESULTS

The variability in disruptive behavior was primarily a function of within-family differences (66%-100%). Consistent with prior genetically informed approaches, the SDP-disruptive behavior association was primarily explained by familial confounds (genetic and environmental). However, when using a multi-rater approach (parents and teachers), results suggest a potentially causal effect of SDP on disruptive behavior (b = 0.09, SE = 0.04, p = 0.03). The potentially causal effect of SDP remained significant in sensitivity analyses.

DISCUSSION

These findings suggest that familial confounding likely plays a complex role in the SDP-disruptive behavior association when examining both parent and teacher reports of behavior. Importantly, the current study highlights the importance of multiple raters, reflecting a more comprehensive measure of complex behaviors (e.g., disruptive behavior) to examine the teratogenic effects of SDP.

IMPLICATIONS

Our study provides additional evidence that controlling for genetic and family factors is essential when examining the effect of SDP on later behavioral problems, as it explains a portion of the association between SDP and later behavioral problems. However, we found a significant association between SDP and disruptive behavior when using a multi-rater approach that capitalizes on both parent and teacher report, suggesting that parent and teacher ratings capture a unique perspective that is important to consider when examining SDP-behavior associations.

Prenatal tobacco use and the risk of mood disorders in offspring: a systematic review and meta-analysis

PURPOSE

It is plausible that offspring born to mothers using tobacco during pregnancy may have increased risk of mood disorders (depression and bipolar disorders); however, mixed results have been reported. We conducted a systematic review and meta-analysis to investigate the magnitude and consistency of associations reported between prenatal tobacco use and mood disorders in offspring.

METHODS

We systematically searched EMBASE, SCOPUS, PubMed and Psych-INFO for studies on mood disorders and prenatal tobacco use. Methodological quality of studies was assessed with the revised Newcastle-Ottawa Scale. We estimated pooled relative risk (RR) with inverse variance weighted random-effects meta-analysis. We performed leave-one-out analyses, and stratified analyses by a subgroup (depression and bipolar disorder). Potential publication bias was assessed by inspection of the funnel plot and Egger's test for regression asymmetry. This study protocol was prospectively registered in PROSPERO (CRD42017060037).

RESULTS

Eight cohort and two case-control studies were included in the final meta-analysis. We found an increased pooled relative risk of mood disorders in offspring exposed to maternal prenatal tobacco use RRs 1.43 (95% CI 1.27-1.60) compared to no prenatal tobacco use. Similarly, the pooled relative risks of bipolar and depressive disorders in offspring were 1.44, (95% CI 1.15-1.80) and 1.44, (95% CI 1.21-1.71), respectively. Moreover, the pooled estimated risk of mood disorders was not significantly attenuated in the studies that reported sibling comparison results [RR = 1.21 (95% CI 1.04-1.41)].

CONCLUSION

Taken together, there was strong evidence for a small (RR < 2) association between prenatal tobacco use and mood disorders in offspring.

The Effect of Smoking during Pregnancy on Severity and Directionality of Externalizing and Internalizing Symptoms: A Genetically Informed Approach

The objective was to examine the association between maternal smoking during pregnancy (SDP) and (I) severity and (II) directionality of externalizing and internalizing symptoms in a sample of sibling pairs while rigorously controlling for familial confounds. The Missouri Mothers and Their Children Study is a family study (N = 173 families) with sibling pairs (aged 7 to 16 years) who are discordant for exposure to SDP. This sibling comparison study is designed to disentangle the effects of SDP from familial confounds. An SDP severity score was created for each child using a combination of SDP indicators (timing, duration, and amount). Principal component analysis of externalizing and internalizing behavior, assessed with the Child Behavior Checklist and Teacher Report Form, was used to create symptom severity and directionality scores. The variance in severity and directionality scores was primarily a function of differences between siblings (71% and 85%, respectively) rather than differences across families (29% and 15%, respectively). The severity score that combines externalizing and internalizing symptom severity was not associated with SDP. However, a significant within-family effect of SDP on symptom directionality (b = 0.07, p = 0.04) was observed in the sibling comparison model. The positive directionality score indicates that SDP is associated with differentiation of symptoms towards externalizing rather than internalizing symptoms after controlling for familial confounds with a sibling comparison model. This supports a potentially causal relationship between SDP and externalizing behavior.

Maternal Smoking During Pregnancy and ADHD: Results From a Systematic Review and Meta-Analysis of Prospective Cohort Studies

Objective: Findings on maternal smoking during pregnancy and ADHD risk in children are inconsistent. A meta-analysis was performed to summarize effects of exposure to maternal smoking during pregnancy on ADHD risk in children. Method: We conducted a systematic literature search to select articles up to June 2016. Only prospective cohort studies were included. Summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated. Results: Pooled RR estimates based on 12 cohort studies including 17,304 pregnant women suggested that maternal smoking during pregnancy was associated with an increased risk of ADHD (pooled RR = 1.58, 95% CI = [1.33, 1.88]). Conclusion: Results from this study indicate that maternal smoking during pregnancy is related to an increased risk of ADHD in children. There is an urgent need to increase maternal awareness of smoking risk and quitting smoking to mitigate the ADHD risk in children.

Association of MTHFR 677C > T and 1298A > C polymorphisms with susceptibility to attention deficit and hyperactivity disorder

Background: The associations of MTHFR polymorphisms with risk of attention deficit and hyperactivity disorder (ADHD) are poorly elucidated. This study was performed to evaluate the association of MTHFR polymorphisms with ADHD risk in Iranian children.Methods: This case-control study included 214 children with ADHD and 220 healthy subjects. The MTHFR 677C > T and 1298A > C polymorphisms were genotyped by an ABI PRISMs 7500 real-time PCR System. The odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association.Results: The MTHFR 1298A > C polymorphism CC genotype (OR= 1.526, 95% CI 1.004-2.320, p = 0.048) and C allele (OR= 1.336, 95% CI 0.1023-1.745, p = 0.034) were associated with an increased risk of ADHD. There was no significant association between MTHFR 677C > T polymorphism and increased risk of ADHD.Conclusions: Our results revealed that the MTHFR 1298A > C polymorphism but not the MTHFR 677 C > T is associated with increased risk of ADHD in Iranian children.

Dimension- and context-specific expression of preschoolers' disruptive behaviors associated with prenatal tobacco exposure

OBJECTIVE

Precise phenotypic characterization of prenatal tobacco exposure (PTE)-related disruptive behavior (DB) that integrates nuanced measures of both exposures and outcomes is optimal for elucidating underlying mechanisms. Using this approach, our goals were to identify dimensions of DB most sensitive to PTE prior to school entry and assess contextual variation in these dimensions.

METHODS

A community obstetric sample of N = 369 women (79.2% lifetime smokers; 70.2% pregnancy smokers) from two Midwestern cities were assessed for PTE using cotinine-calibrated interview-based reports at 16, 28, and 40 weeks of gestation. A subset of n = 244 who completed observational assessments with their 5-year-old children in a subsequent preschool follow-up study constitute the analytic sample. Using two developmentally-meaningful dimensions previously associated with emergent clinical risk for DB-irritability and noncompliance-we assessed children with 2 parent-report scales: the Multidimensional Assessment Profile of Disruptive Behavior (MAP-DB) and the Early Childhood Inventory (ECI). We also assessed children by direct observation across 3 interactional contexts with the Disruptive Behavior Diagnostic Observation Schedule (DB-DOS). We used generalized linear models to examine between-child variability across behavioral dimensions, and mixed effects models to examine directly observed within-child variability by interactional context.

RESULTS

Increasing PTE predicted increasing impairment in preschoolers' modulation of negative affect (irritability), but not negative behavior (noncompliance) across reported (MAP-DB) and observed (DB-DOS) dimensional measures. Moreover, children's PTE-related irritability was more pronounced when observed with parents than with the examiner. The ECI did not detect PTE-related irritability nor noncompliance.

CONCLUSIONS

Nuanced, dimension- and context-specific characterization of PTE-related DB described can optimize early identification of at-risk children.

Metabolic changes in early neonatal life: NMR analysis of the neonatal metabolic profile to monitor postnatal metabolic adaptations

BACKGROUND

A major challenge from the moment a child is delivered is the adaptation to the extrauterine life, where rapid metabolic changes take place. The study of these changes during the first days of human life may assist in the understanding of the metabolic processes that occur at this critical period, which is likely to provide significant clinical insights. To date, metabolomics has become a powerful field, ideal for the monitoring of such dynamic variations, since it offers the possibility to identify alterations in metabolic profiles, even on daily basis.

METHODS

The study included 253 healthy newborns (GA 35 to 40 weeks) from the region of Western Greece. Urine samples were collected immediately after birth and at the third day of life. NMR-based metabolomics was used to compare the metabolic urinary profiles of newborns from the first and third day of their life, assessing the impact of six perinatal factors; delivery mode, prematurity, maternal smoking, gender, nutrition and neonatal jaundice.

RESULTS

Analysis of urine metabolic fingerprint from the first and third day of life, coupled with multivariate statistics, provides insights into the details of early life metabolic profile differentiation. Αt the third day of life metabolic adaptations are evident, as many differences were noted in urine of healthy neonates within the first 72 h postpartum. Trends in differentiation of metabolites levels between the two groups, late preterm and term newborns, have been also observed.

CONCLUSIONS

Newborn's urine metabolic profiles confirmed the rapid changes in their metabolism after birth. Further, ongoing research will enable us to develop one reference model of urinary metabolomics in healthy newborns during the period of adaptation to the extra-uterine life.

The effect of quitting water pipe during pregnancy on anthropometric measurements at birth: a population-based prospective cohort study in the south of Iran

BACKGROUND

Evidence regarding health effects of tobacco cessation during pregnancy is mainly restricted to cigarette while water pipe is the preferred method of tobacco smoking among women in the Middle-East. The present study aimed to assess the effects of cessation of water pipe during pregnancy on birth anthropometric measures in the south of Iran.

METHODS

Data on 1120 singleton pregnancies (response rate = 93.4%) from a population-based prospective cohort study in suburban communities in Bandar Abbas city was used. Based on water pipe smoking status, the study subjects were categorized into: 1) those who never smoke water pipe (never smoker); 2) those who stopped water pipe during pregnancy and resumed it postpartum (quitters); 3) those who continued smoking water pipe during their pregnancy (always smokers). The Generalized Linear Models (GLMs) were utilized for the analyses.

RESULTS

Compared to never smokers, quitting water pipe in pregnancy decreased mean birthweight of infants by 99.30 g (β:-99.30, 95%CI:-204.35,-5.75) and an additional decrease of 37.83 g occurred in infants of always smokers (β:-137.13;95%CI:- 262.21,-12.05). Means of birth length did not significantly differ among the three water pipe groups. Means of head circumference, however, significantly increased by 0.79 cm in infants of always smokers (β:079,95%CI:0.13,1.45).

CONCLUSION

Quitting water pipe during pregnancy had positive effects on infant growth, especially birth weight. Awareness campaigns about health benefits of quitting water pipe during routine prenatal checkups and integration of active follow-up visits into prenatal care protocols for smoking mothers are provided.

Influence of Family Environment and Tobacco Addiction: A Short Report from a Post-Graduate Teaching Hospital, India

Background: The initiation of tobacco addiction is complex, and several factors contribute to the onset of this behavior. It is presumed that the influence of family environment may pose a key factor in tobacco addiction. Tobacco-use has been highly observed in the Jamnagar district of Saurashtra region of Gujarat, India. No earlier study has focused on determining the pervasiveness of tobacco-use in families of tobacco users and non-users in this geographical area. Thus, this study aimed to assess the practice and pattern of tobacco-use (smoking and/or tobacco-chewing) in the families of tobacco-user patients. Methods: We studied the families of 65 tobacco-user patients (Group 1) who visited an outpatient clinic of an Ayurvedic post-graduate hospital with complaints of cough were studied and compared with age and gender-matched non-tobacco users (Group 2). The prevalence of tobacco use among the parents, siblings, and children of both groups was analyzed and compared. Results: The findings revealed that tobacco use among parents, siblings, and children in Group 1 was higher than Group 2 (p < 0.001). This meant that the problems of tobacco addiction are not always related to the individual, and therefore, tobacco-prevention strategies should focus on the entire family. Conclusions: These findings offer further insight into the promotion of smoking prevention interventions. Nevertheless, further research is warranted.

Parental tobacco smoking and risk of childhood leukemia in Costa Rica: A population-based case-control study

INTRODUCTION

The role of environmental and behavioral exposures on childhood leukemia etiology is poorly understood. We examined the association of maternal and paternal tobacco smoking at different time points with the risk of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) in Costa Rican children.

MATERIALS AND METHODS

We conducted a population-based case-control study on childhood leukemia in Costa Rica. Cases (n ALL = 252; n AML = 40) were diagnosed between 1995 and 2000 (aged <15 years at diagnosis) and identified from the Costa Rican Cancer Registry and the National Children's Hospital. A total of 578 frequency-matched population controls were sampled from the National Birth Registry. Parental tobacco smoking was assessed via face-to-face interviews. We used logistic regression models to examine the association of paternal and maternal tobacco smoking before conception, during pregnancy, and after birth with childhood ALL and AML risk, adjusted for child sex, birth year, maternal/paternal age, and parental education.

RESULTS

Paternal smoking before conception, during pregnancy, and after birth was associated with an increased risk of childhood AML (Odds Ratio (OR): 2.51, 95% CI: 1.21-5.17; OR: 3.21, 95% CI: 1.56-6.60; and OR: 2.83, 95% CI: 1.36-5.90, respectively). Maternal smoking during pregnancy was also associated with a modest, but imprecise increase in AML risk. We observed null associations of maternal and paternal smoking with ALL in the offspring.

CONCLUSION

Our results suggest an association between parental smoking and risk of AML, but not ALL, in Costa Rican children. These findings add to the established evidence of numerous health risks associated with smoking and highlight the potential harm of smoking during sensitive windows of the development of fetus and child.

ADHD symptoms induced by prenatal methamphetamine exposure

Methamphetamine is commonly used psychostimulant in the Czech Republic and is often abused by pregnant women. Methamphetamine may cause abnormalities in placenta and umbilical cord that results in hypoxia and malnutrition. ADHD is a mental disorder with a heterogeneous origin. The number of patients suffering from ADHD is growing. The pathophysiological mechanisms causing ADHD have not yet been clarified. There are very few rat models for ADHD and include genetic models, chemically induced models (ethanol, nicotine, PCBs, 6-hydroxydopamine lesion) or environmentally induced models (anoxia). The aim of the present study was to test prenatal methamphetamine exposure (5 mg/kg) as a potential novel animal model for ADHD. We found that adult male offspring prenatally exposed to methamphetamine presented hyperactivity while exploring novel environments. Together with cognition changes found in our previous studies, these might represent symptoms similar to those seen in ADHD. More experiments are planned to investigate our hypothesis.

What lessons have we learnt about the impact of maternal cigarette smoking from animal models?

Maternal first- or second-hand tobacco smoking during pregnancy is still common albeit that the detrimental effects to the unborn child are well known. Maternal tobacco cigarette smoking can affect multiple organ systems in the offspring, rendering them at increased risk of various conditions throughout life (eg. intrauterine underdevelopment, asthma, substance abuse, diabetes). However, this review will only focus on its impact on the brain and the related molecular changes in the offspring based on evidence from animal studies. Although epidemiological studies have identified the associations between maternal cigarette smoke exposure (SE) and brain disorders, animal models can help identify the underlying mechanisms and test interventions. Human studies have found that maternal SE is closely linked to small brain size and changes in brain structure and associated with a high risk of cognitive defects. Animal models suggest that this may be due to increased brain oxidative stress and inflammation during the neonatal period, leading to increased brain cell apoptosis in adulthood. There is a distinct gender bias of such impacts, where male offspring are more affected than females. Female offspring seem to have developed the adaptation by increasing endogenous antioxidant levels. Indeed, animal studies have shown that using antioxidant supplementation during pregnancy can improve neurological outcomes in male offspring, however, the efficacy in humans is yet to be confirmed. Furthermore, some animal studies suggested nicotine as the key player in intrauterine underdevelopment due to maternal SE, while human clinical trials using nicotine replacement therapy do not support this mechanism. This review will discuss the possible reasons.