Maternal smoking during pregnancy and fetal organ growth: a magnetic resonance imaging study

The human placental methylome

This review provides an overview of the unique features of DNA methylation in the human placenta. We discuss the importance of understanding placental development, structure, and function in the interpretation of DNA methylation data. Examples are given of how DNA methylation is important in regulating placental-specific gene expression, including monoallelic expression and X-chromosome inactivation in the placenta. We also discuss studies of global DNA methylation changes in the context of placental pathology and environmental exposures.

Saguenay Youth Study: a multi-generational approach to studying virtual trajectories of the brain and cardio-metabolic health

This paper provides an overview of the Saguenay Youth Study (SYS) and its parental arm. The overarching goal of this effort is to develop trans-generational models of developmental cascades contributing to the emergence of common chronic disorders, such as depression, addictions, dementia and cardio-metabolic diseases. Over the past 10 years, we have acquired detailed brain and cardio-metabolic phenotypes, and genome-wide genotypes, in 1029 adolescents recruited in a population with a known genetic founder effect. At present, we are extending this dataset to acquire comparable phenotypes and genotypes in the biological parents of these individuals. After providing conceptual background for this work (transactions across time, systems and organs), we describe briefly the tools employed in the adolescent arm of this cohort and highlight some of the initial accomplishments. We then outline in detail the phenotyping protocol used to acquire comparable data in the parents.

Fetal Smoke Exposure and Kidney Outcomes in School-Aged Children

BACKGROUND

Fetal smoke exposure may result in developmental adaptations that permanently affect the developing kidney. In this study, the associations of maternal and paternal smoking during pregnancy with childhood kidney size and function were assessed.

STUDY DESIGN

Prospective cohort study from fetal life onward.

SETTING & PARTICIPANTS

This study was conducted in a group of 5,622 children in Rotterdam, the Netherlands.

PREDICTORS

Maternal and paternal smoking were assessed during pregnancy by questionnaires.

OUTCOMES & MEASUREMENTS

At a median age of 6.0 (5th-95th percentile, 5.6-7.9) years, we measured childhood kidney volumes, estimated glomerular filtration rate (eGFR), and albumin-creatinine ratio.

RESULTS

The confounder model, which included size at birth, shows that compared with children from mothers who did not smoke during pregnancy, those from mothers who continued smoking during pregnancy had smaller combined kidney volumes at the age of 6 years. The strongest effect estimate was observed for mothers who smoked 5 or more cigarettes per day during pregnancy (difference for combined kidney volume, -2.80 [95% CI, -5.15 to -0.45] cm(3)). Similarly, continued maternal smoking during pregnancy also was associated with a lower eGFR in childhood (difference, -2.25 [95% CI, -3.70 to -0.79] mL/min/1.73 m(2)). First-trimester-only smoking was associated with a higher risk of increased albumin-creatinine ratio (OR, 1.45; 95% CI, 1.05-2.01). Among mothers who did not smoke during pregnancy, paternal smoking was associated with smaller childhood combined kidney volume (difference, -1.78 [95% CI, -3.48 to -0.07] cm(3)), but not with childhood kidney function measures.

LIMITATIONS

Smoking behavior was measured with questionnaires. Follow-up measurements were available for only 70% of the children.

CONCLUSIONS

Continued maternal smoking during pregnancy is associated with smaller combined kidney volume and lower eGFR in school-aged children. Stronger effect estimates for maternal versus paternal smoking suggest that intrauterine adaptive responses may play a role as underlying mechanisms.

Smoking during pregnancy affects foetal brain development

Environmental factors such as maternal smoking can significantly modulate genetically programmed brain development during foetal life. This review looks at how prenatal smoking exposure modulates brain development, including new evidence on the effects of smoking on foetal brain development and function.

CONCLUSION

Smoking during pregnancy exposes the foetus to thousands of health-threatening chemicals, restricting foetal body and head growth. Alterations in brain structure and function have been seen in children exposed to prenatal smoking.

Effect of nicotine patches in pregnancy on infant and maternal outcomes at 2 years: follow-up from the randomised, double-blind, placebo-controlled SNAP trial

BACKGROUND

The SNAP (Smoking and Nicotine in Pregnancy) trial compared nicotine replacement therapy (NRT) patches with placebo in pregnant smokers; although NRT doubled cessation rates in the first 4 weeks, by delivery no differences in maternal smoking or birth outcomes were noted. As a result, NRT used in standard doses during pregnancy is considered ineffective for smoking cessation. Subsequent effects of NRT on the children of treated mothers are unknown because no trials have investigated the effect of gestational NRT use beyond birth. To assess whether NRT use in pregnancy might cause harm to infants, we aimed to compare effects of NRT and placebo on infant development 2 years after delivery.

METHODS

1050 pregnant smokers aged 16-45 years, at 12-24 weeks' gestation, and smoking at least five cigarettes per day were recruited from seven hospitals in England between May 1, 2007, and Feb 26, 2010, and followed up until their infants were 2 years old. Participants were randomly assigned (1:1) to receive up to 8-weeks treatment with NRT (15 mg/16 h transdermal patches) or identically packaged and visually matched placebo patches (all patches manufactured by and purchased at market rate from United Pharmaceuticals, Amman, Jordan), issued as two 4-week supplies (521 for NRT group, 529 for placebo group) [Corrected]. Randomisation was stratified by site with participants, health-care professionals, and research staff masked to treatment allocation. The primary results for participants and infants at delivery were published in 2012; we present results from the trial cohort 2 years after birth. After delivery, questionnaires were posted to participants and, if there was no response, to family physicians. The primary outcome at 2 years was infants' survival without developmental impairment (ie, no disability or problems with behaviour or development). Treatment groups were compared on an intention-to-treat basis. The trial is registered with Controlled-Trials.com, number ISRCTN07249128.

FINDINGS

Questionnaires were returned at 2 years for 891 (88%) of 1010 live singleton births (445 of (88%) 503 given NRT and 446 (88%) of 507 given placebo). Because of missing data, developmental outcomes, including four infant deaths, were documented for 888 of (88%) 1010 singleton infants; 445 (88%) of 503 infants in NRT group and 443 (87%) of 507 infants in placebo. In the NRT group, 323 (73%) of 445 infants had no impairment compared with 290 (65%) of 443 infants in the placebo group (odds ratio [OR] 1.40, 95% CI 1.05-1.86, p=0.023). At 2 years, 15 (3%) of 521 mothers in the NRT group and nine (2%) of 529 mothers in the placebo groups self-reported prolonged smoking abstinence since a quit date set in pregnancy (OR 1.71, 95% CI 0.74-3.94, p=0.20). Adverse events were not collected after delivery, but previously reported adverse pregnancy and birth outcomes were similar in the two groups.

INTERPRETATION

Infants born to women who used NRT for smoking cessation in pregnancy were more likely to have unimpaired development. NRT had no effect on prolonged abstinence from smoking but did cause a temporary doubling of smoking cessation shortly after randomisation during pregnancy, which could explain findings. If findings are confirmed by subsequent research, this has potential implications for the management of smoking in pregnancy.

FUNDING

National Institute for Health Research Health Technology Assessment Programme.

Quantitative magnetic resonance imaging of the fetal brain in utero: Methods and applications

Application of modern magnetic resonance imaging (MRI) techniques to the live fetus in utero is a relatively recent endeavor. The relative advantages and disadvantages of clinical MRI relative to the widely used and accepted ultrasonographic approach are the subject of a continuing debate; however the focus of this review is on the even younger field of quantitative MRI as applied to non-invasive studies of fetal brain development. The techniques covered under this header include structural MRI when followed by quantitative (e.g., volumetric) analysis, as well as quantitative analyses of diffusion weighted imaging, diffusion tensor imaging, magnetic resonance spectroscopy and functional MRI. The majority of the published work reviewed here reflects information gathered from normal fetuses scanned during the 3^rd trimester, with relatively smaller number of studies of pathological samples including common congenital pathologies such as ventriculomegaly and viral infection.

Identifying craniofacial features associated with prenatal exposure to androgens and testing their relationship with brain development

We used magnetic resonance (MR) images obtained in same-sex and opposite-sex dizygotic twins (n = 119, 8 years of age) to study possible effects of prenatal androgens on craniofacial features. Using a principal component analysis of 19 craniofacial landmarks placed on the MR images, we identified a principal component capturing craniofacial features that distinguished females with a presumed differential exposure to prenatal androgens by virtue of having a male (vs. a female) co-twin (Cohen's d = 0.76). Subsequently, we tested the possibility that this craniofacial "signature" of prenatal exposure to androgens predicts brain size, a known sexually dimorphic trait. In an independent sample of female adolescents (singletons; n = 462), we found that the facial signature predicts up to 8% of variance in brain size. These findings are consistent with the organizational effects of androgens on brain development and suggest that the facial signature derived in this study could complement other indirect measures of prenatal exposure to androgens.

The impact of maternal cigarette smoke exposure in a rodent model on renal development in the offspring

This study aimed to investigate whether maternal cigarette smoke exposure can disrupt fetal kidney development by changing the expression of growth and transcription factors essential for renal development, and thereafter predispose the offspring to chronic kidney disease later in life. Female Balb/c mice (6 weeks) were exposed either to cigarette smoke or air under identical conditions, 6 weeks prior to mating, during gestation and during lactation. Male offspring were sacrificed at three time points, postnatal day (P)1, P20 (weaning age), and 13 weeks (mature age). Blood, urine, and kidneys were collected for analysis. At P1, the developmental genes fibroblast growth factor 2, glial cell-line derived neurotrophic factor and paired box 2 were upregulated at mRNA and protein levels; whilst fibroblast growth factor (FGF) 7 and FGF10 were downregulated. At P20, mRNA expression of FGF2, FGF10 and Wingless-type 4 was upregulated by maternal smoke exposure. These changes were normalised in adulthood. Nephron development was delayed, with fewer nephron numbers from P1 persisted to adulthood; while glomerular volume was increased at P20 but reduced in adulthood. Pro-inflammatory marker monocyte chemoatractant protein 1 (MCP1) was increased in the kidney by maternal smoke exposure. These changes were accompanied by an increased albumin/creatinine ratio in adulthood, suggesting reduced renal dysfunction. In conclusion maternal cigarette smoke exposure prior to and during pregnancy, as well as lactation leads to significant renal underdevelopment and functional abnormalities in adulthood. This study confirms the hypothesis that maternal smoking predisposes offspring to chronic kidney disorders.

The Effects of Preeclampsia on Perinatal Risks and Infant Temperaments Among Mothers With Antenatal Depression

IMPORTANCE

Preeclampsia and depression are two most prevalent disorders known to affect pregnant women and unborn infant. However, few studies have prospectively examined the adverse influence of the in-utero exposures to the two disorders on the optimal development in their offspring, including mortality, adverse birth outcomes, and infant temperament styles.

OBJECTIVES

(1) To examine whether exposures to preeclampsia and antenatal depression were associated with developmental indices of offspring at birth and temperament at 3 months; and (2) To evaluate how preeclampsia and antenatal depression associated with offspring temperamental style.

DESIGN

Prospective cohort study with regular assessment of mother's blood pressure at each prenatal visit: offspring were followed till 3 months.

SETTING

Two prenatal clinics, New York City, USA.

PARTICIPANTS

A cohort of 233 pregnant women was followed throughout pregnancy. Of those, 141 provided ratings of infant temperament at three months.

EXPOSURES

Diagnostic outcome of maternal depression by clinical interviewers blind to preeclampsia status, were ascertained using the Structured Clinical Interview for DSM-IV Axis I Disorders. The development of preeclampsia, defined by the onset of hypertension (> 140/90 mm HG) after 20 weeks' gestation, accompanied by 300 mg of protein, monitored via electronic medical records.

MAIN OUTCOME MEASURES

Birth outcomes were assessed via standardized ratings at delivery. Infant temperament was reported by the mother at three months, using 91-item IBQ-R (Infant Behavioral Questionnaire-Revised).

RESULTS

Preeclampsia was associated with an over 5-fold increased risk for fetal/infant mortality, a 3- to 7-fold increased risk for poorer birth outcomes, and flatter affect and distress in infants. Furthermore, infants born to preeclamptic mothers with co-occurring depression displayed lower levels of smile/laughter, high-intensity pleasure seeking behavior, perceptual sensitivity, and approach behavior.

CONCLUSION

Preeclampsia was associated with a few difficult temperament styles in the first three months after birth. Moreover, its negative impact was amplified by mother's antenatal depression. Our findings regarding additive risk for negative infant outcomes in babies exposed to preeclampsia and antenatal depression suggests that the development of early detection programs to identify and monitor women who are at heightened risk for these conditions can potentially have a positive influence on long-term infant neurobehavioral development.

Stressful events and continued smoking and continued alcohol consumption during mid-pregnancy

Aim

to examine whether the severity of different categories of stressful events is associated with continued smoking and alcohol consumption during mid-pregnancy. Also, we explored the explanation of these associations by anxiety and depressive symptoms during pregnancy. Finally, we studied whether the severity of stressful events was associated with the amount of cigarettes and alcohol used by continued users.

Method

we conducted a cross-sectional analysis using data from a population-based prospective cohort study. Pregnant women were recruited via midwifery practices throughout The Netherlands. We analyzed women who continued smoking (n = 113) or quit (n = 290), and women who continued alcohol consumption (n = 124) or quit (n = 1403) during pregnancy. Smoking, alcohol consumption, and perceived severity of stressful events were measured at 19 weeks of gestation. The State Trait Anxiety Inventory and the Edinburgh Postnatal Depression Scale were filled out at 14 weeks of gestation. Odds ratios were calculated as association measures and indicated the relative increase for the odds of continuation of smoking and alcohol consumption for the maximum severity score compared to the minimum score.

Findings

severity of the following stressful event categories was associated with continued alcohol consumption: ‘conflict with loved ones’ (OR = 10.4, p<0.01), ‘crime related’ (OR = 35.7, p<0.05), ‘pregnancy-specific’ (OR = 13.4, p<0.05), and the total including all events (OR = 17.2, p<0.05). Adjustment for potential confounders (age, parity and educational level) did not notably change the estimates. There was no association of anxiety and depressive symptoms with continued smoking or alcohol consumption. No associations emerged for continued smoking and severity of stressful events. The amount of cigarettes and alcohol consumption among continued users was not associated with severity of stressful events.

Conclusions

Our findings may be relevant for health care providers, in particular midwives and general practitioners. The impact of stressful events may be considered when advising pregnant women on smoking and alcohol consumption.

Neuropathology of cigarette smoking

It is well established that cigarette smoking is hazardous to health and is a risk factor for many chronic diseases. However, its impact on the brain, whether it be from prenatal exposure to maternal cigarette smoking, cerebrovascular disease, Alzheimer's disease (AD) or Parkinson's disease, is still not very clear. Neuroimaging and neuropathological investigations suggest that there are heterogeneous effects of cigarette smoking on the brain. On the one hand, it is quite clear that cigarette smoking causes damage to endothelial cells, resulting in increased risk of cerebrovascular disease. On the other hand, it seems to be associated with different Alzheimer's pathologies in post-mortem brains and experimental models, despite the fact that epidemiological studies clearly indicate a positive correlation between cigarette smoking and increased risk for AD. Interestingly, cigarette smoking appears to be associated with reduced Parkinson's pathology in post-mortem brains. However, although nicotine in cigarettes may have some neuroprotective actions, the effects of all the other toxic compounds in cigarettes cannot be ignored. It is, therefore, our aim to summarize what is known about the neuropathology of cigarette smoking and, in particular, its implications for neurodegenerative diseases.