Smoking during pregnancy increases risks of various obstetric complications: a case-cohort study of the Japan Perinatal Registry Network database

Smoking and recurrent pregnancy loss: A cohort study of 2829 women

Smoking during pregnancy is associated with negative reproductive outcome. Less is known about the impact of smoking or previous smoking in women with recurrent pregnancy loss (RPL) which this study aimed to investigate. We included all women <42 years (n=2829) referred to a RPL unit at Copenhagen University Hospital between January 2000 and December 2021 in the cohort with follow-up until June 2022. Patients were categorized as 'smokers at time of referral', 'never-smokers' or 'former smokers'. The main outcomes were pregnancy history prior to referral, prospective pregnancy rate, live birth rate, rates of ectopic pregnancy, and stillbirth. At referral, smokers (n=373) were on average 2.0 years younger (P<0.001) and had experienced significantly more pregnancy losses (P<0.001), and stillbirths (P=0.01) compared to never-smokers (n=2100). Former smokers had a higher risk of stillbirth prior to referral compared to never-smokers but no differences in pregnancy rate or other outcomes. Prospective pregnancy rates were lower for smokers compared with never-smokers (71.8% vs. 77.5%, P=0.02). Live birth rate was 58.0% for the 243 women who smoked at referral compared to 61.4% for the 1488 never-smokers (P=0.32). Stillbirth and ectopic pregnancies were significantly more common for smokers (2.8% vs. 0.4%, P=0.01; 6.0% vs. 2.0%, P<0.008). Women with RPL who smoked at referral were referred younger with a higher number of previous pregnancy losses and stillbirths compared with never-smokers. Fewer smokers achieved a pregnancy after referral but those who did had a similar live birth rate compared to never-smokers, although stillbirths and ectopic pregnancies were more common.

Association Between Smoking and Hypertension in Pregnancy Among Japanese Women: A Meta-analysis of Birth Cohort Studies in the Japan Birth Cohort Consortium (JBiCC) and JECS

BACKGROUND

Recent literature suggest the effect of maternal smoking on risk of hypertensive disorders in pregnancy (HDP) and preeclampsia may differ by ethnicity; however, studies on Asians are limited.

METHODS

We investigated the association of maternal smoking with HDP and preeclampsia using a common analysis protocol to analyze the association in six birth cohorts participating in a Japanese consortium of birth cohorts (JBiCC). Results were compared with-published results from cohorts not included in this consortium, and, where possible, we produced a meta-analysis including these studies.

RESULTS

Meta-analysis of four cohort studies including 28,219 participants produced an odds ratio (OR) of 1.24 (95% confidence interval [CI], 0.88-1.87) for the effect of smoking beyond early pregnancy compared to women who did not smoke during pregnancy. These results combined with those from the Japan Environment and Children's Study (JECS) yielded an OR of 1.19 (95% CI, 1.00-1.43, P = 0.056). Meta-analysis results for categories of smoking volume were insignificant, but when combined with JECS yielded an OR of 0.86 (95% CI, 0.65-1.12) for smoking 1-4 cigarettes, 1.25 (95% CI, 0.98-1.60) for smoking 5-9 cigarettes, and 1.27 (95% CI, 1.04-1.54) for smoking 10 or more cigarettes per day. All effects were insignificant for preeclampsia.

CONCLUSION

Our results suggest that the protective effects of smoking longer and smoking more on HDP and preeclampsia repeatedly observed among Europeans and North Americans likely do not hold for the Japanese.

Prepregnancy body mass index and glycated albumin in the third trimester may predict infant complications in gestational diabetes mellitus: a retrospective cohort study

Background

Maternal hyperglycemia, obesity, and hypertension with gestational diabetes mellitus (GDM) are risk factors for infant complications. This study aimed to investigate maternal factors and glycemic control indicators that affect infant complications in GDM.

Methods

We conducted a retrospective cohort study including 112 mothers with GDM and their infants. Multivariate logistic regression analysis was used to investigate the variables associated with good and adverse infant outcomes. We determined the cutoff values of variables that showed a significant difference in the multivariate logistic regression analysis for predicting infant complications by performing receiver operating characteristic curve analysis.

Results

In the multivariate logistic regression analysis, prepregnancy BMI and GA in the third trimester were significantly related to good and adverse infant outcomes (adjusted odds ratios [aORs], 1.62; 95% CIs 1.17-2.25, p = 0.003 and aORs, 2.77; 95% CIs 1.15-6.64, p = 0.022, respectively). The cutoff values for prepregnancy BMI and GA in the third trimester were 25.3 kg/m2 and 13.5%, respectively.

Conclusions

The importance of weight control before pregnancy and the usefulness of GA in the third trimester to predict infant complications were suggested in this study.

Pregnancy, infection, and epigenetic regulation: A complex scenario

A unique immunological condition, pregnancy ensures fetus from maternal rejection, allows adequate fetal development, and protects against microorganisms. Infections during pregnancy may lead to devastating consequences for pregnant women and fetuses, resulting in the mother's death, miscarriage, premature childbirth, or neonate with congenital infection and severe diseases and defects. Epigenetic (heritable changes in gene expression) mechanisms like DNA methylation, chromatin modification, and gene expression modulation during gestation are linked with the number of defects in the fetus and adolescents. The feto-maternal crosstalk for fetal survival during the entire gestational stages are tightly regulated by various cellular pathways, including epigenetic mechanisms that respond to both internal as well outer environmental factors, which can influence the fetal development across the gestational stages. Due to the intense physiological, endocrinological, and immunological changes, pregnant women are more susceptible to bacterial, viral, parasitic, and fungal infections than the general population. Microbial infections with viruses (LCMV, SARS-CoV, MERS-CoV, and SARS-CoV-2) and bacteria (Clostridium perfringens, Coxiella burnetii, Listeria monocytogenes, Salmonella enteritidis) further increase the risk to maternal and fetal life and developmental outcome. If the infections remain untreated, the possibility of maternal and fetal death exists. This article focused on the severity and susceptibility to infections caused by Salmonella, Listeria, LCMV, and SARS-CoV-2 during pregnancy and their impact on maternal health and the fetus. How epigenetic regulation during pregnancy plays a vital role in deciding the fetus's developmental outcome under various conditions, including infection and other stress. A better understanding of the host-pathogen interaction, the characterization of the maternal immune system, and the epigenetic regulations during pregnancy may help protect the mother and fetus from infection-mediated outcomes.

Active or passive maternal smoking increases the risk of low birth weight or preterm delivery: Benefits of cessation and tobacco control policies

In France, maternal smoking, active or passive, remains one of the highest in Europe. At the same time, there is an increase in the number of low birth weight (<2500 g) and premature (<37 weeks of amenorrhea) newborns. The objective of this narrative review is to examine the impact of active or passive maternal smoking on birth weight or prematurity rates, and to consider the benefits of policies to stop or control smoking. This is a narrative review that analyzes and discusses the major articles published over the past 20 years regarding the role of active or passive maternal smoking on the risk of low birth weight or preterm delivery. Articles were selected using the following keywords: maternal smoking, low birth weight, preterm birth, smoking cessation, passive smoking, exhaled carbon monoxide, tobacco control policies. Active smoking is associated, in a dose-response relationship, with increased risks of low birth weight and preterm delivery. Passive smoking, mainly related to the presence of a smoking spouse, increases the risk of low birth weight and preterm birth. Our review confirmed also the benefits of smoking cessation, even in the third trimester, in reducing the risk of small for gestation age or fetal growth restriction and preterm birth. Several studies of tobacco control policies have been shown to be effective in significantly reducing maternal smoking. There is sufficient evidence to infer a causal link between active or passive maternal smoking and low birth weight or preterm delivery. This causal link is compelling and sufficient to justify intensifying efforts to promote rapid progress in tobacco control policies, with the vision of a tobacco-free generation, and smoking cessation with best practices during preconception or pregnancy.

PRENATAL MATERNAL CHARACTERISTICS ASSOCIATED WITH RETINOPATHY OF PREMATURITY

PURPOSE

Determine whether prenatal maternal characteristics such as sociodemographic characteristics, comorbidities, or pregnancy complications affect retinopathy of prematurity (ROP) development.

METHODS

Medical records of 236 mother-infant dyads from our institution were reviewed, only including dyads in which infants were born at 30 weeks gestational age or earlier. The primary outcome measure was the risk of ROP (defined Stage 1 or greater in either eye) and its association with prenatal maternal variables.

RESULTS

Maternal Medicaid insurance, smoking during pregnancy, and chorioamnionitis were associated with an increased risk of ROP. For Medicaid insurance and chorioamnionitis, these risks were not appreciably altered by adjustment for potential confounders.

CONCLUSION

These results suggest that several prenatal maternal factors may independently affect the risk of ROP in preterm infants. Validation of our findings could aid in the identification of infants at high risk for ROP based on prenatal clinical features.

The relation between cigarette smoking with delivery outcomes. An evaluation of a database of more than nine million deliveries

OBJECTIVES

Smoking in pregnancy is associated with an increased risk of preterm birth (PTB), intrauterine growth restriction, placental abruption and perinatal death. The association between smoking and other delivery outcomes, such as chorioamnionitis, mode of delivery or postpartum hemorrhage (PPH), however, is insufficient as only few studies addressed these issues. The aim of the study was to evaluate the association between prenatal smoking and delivery outcomes in a large database, while controlling for confounding effects.

METHODS

A retrospective population-based study using data from the Healthcare Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS). A dataset of all deliveries between 2004 and 2014 (inclusively) was created. Our control group included all pregnant women who did not smoke during pregnancy, which was compared to pregnant women who smoked. A multivariate logistic analysis was conducted, adjusting for any statistically significant confounding effects.

RESULTS

Our study identified 9,096,788 births between 2004 and 2014. Of which, 443,590 (4.8%) had a documented diagnosis of smoking. A significantly higher risk was found for PTB (odds ratio 1.39, CI 1.35-1.43), preterm premature rupture of membranes (odds ratio 1.52, CI 1.43-1.62) and small for gestational age (SGA) neonates (odds ratio 2.27, CI 2.19-2.35). The risks of preeclampsia (odds ratio 0.82, CI 0.78-0.85), chorioamnionitis (odds ratio 0.88, CI 0.83-0.4), PPH (odds ratio 0.94 CI 0.9-0.98) and operative vaginal delivery (odds ratio 0.9, CI 0.87-0.94) were lower among smokers.

CONCLUSIONS

This large database confirms the findings of previous smaller studies, according to which smoking decreases the risk of preeclampsia while increasing the risk of PTB and SGA neonates. The current study also revealed a decreased risk for PPH as well as for chorioamnionitis among pregnant smokers.

Exposure to chemical components of fine particulate matter and ozone, and placenta-mediated pregnancy complications in Tokyo: a register-based study

BACKGROUND

Maternal exposure to fine particulate matter (PM_2.5) was associated with pregnancy complications. However, we still lack comprehensive evidence regarding which specific chemical components of PM_2.5 are more harmful for maternal and foetal health.

OBJECTIVE

We focused on exposure over the first trimester (0-13 weeks of gestation), which includes the early placentation period, and investigated whether PM_2.5 and its components were associated with placenta-mediated pregnancy complications (combined outcome of small for gestational age, preeclampsia, placental abruption, and stillbirth).

METHODS

From 2013 to 2015, we obtained information, from the Japan Perinatal Registry Network database, on 83,454 women who delivered singleton infants within 23 Tokyo wards (≈627 km²). Using daily filter sampling of PM_2.5 at one monitoring location, we analysed carbon and ion components, and assigned the first trimester average of the respective pollutant concentrations to each woman.

RESULTS

The ORs of placenta-mediated pregnancy complications were 1.14 (95% CI = 1.08-1.22) per 0.51 μg/m³ (interquartile range) increase of organic carbon and 1.11 (1.03-1.18) per 0.06 μg/m³ increase of sodium. Organic carbon was also associated with four individual complications. There was no association between ozone and outcome.

SIGNIFICANCE

There were specific components of PM_2.5 that have adverse effects on maternal and foetal health.

Heated tobacco product use and hypertensive disorders of pregnancy and low birth weight: analysis of a cross-sectional, web-based survey in Japan

OBJECTIVES

Knowledge on the impact of heated tobacco product (HTP) use in pregnant women with associated maternal and neonatal risks for hypertensive disorders of pregnancy (HDP) and low birth weight (LBW) is limited. We aimed to assess the status of HTP use among pregnant women in Japan and explore the association of HTP use with HDP and LBW.

DESIGN

Cross-sectional study.

SETTING

Data from the Japan 'COVID-19 and Society' Internet Survey study, a web-based nationwide survey.

PARTICIPANTS

We investigated 558 postdelivery and 365 currently pregnant women in October 2020.

PRIMARY AND SECONDARY OUTCOME MEASURES

Information on HDP and LBW was collected from the postdelivery women's Maternal and Child Health Handbooks (maternal and newborn records). We estimated the age-adjusted ORs and 95% CIs of ever HTP smokers for HDP and LBW and compared them with those of never HTP smokers in a logistic regression analysis.

RESULTS

The prevalence of ever and current HTP use were 11.7% and 2.7% in postdelivery women and 12.6% and 1.1% in currently pregnant women, respectively. Among currently pregnant women who were former combustible cigarette smokers, 4.4% (4/91) were current HTP smokers. Among postdelivery women, ever HTP smokers had a higher HDP incidence (13.8% vs 6.5%, p=0.03; age-adjusted OR=2.48, 95% CI 1.11 to 5.53) and higher LBW incidence (18.5% vs 8.9%, p=0.02; age-adjusted OR=2.36, 95% CI 1.16 to 4.87).

CONCLUSIONS

In Japan, the incidence of ever HTP use exceeded 10% among pregnant women, and HTP smoking may be associated with maternal and neonatal risks.

The association between smoking during pregnancy and hypertensive disorders of pregnancy: A systematic review and meta-analysis

BACKGROUND

Smoking is a major public health problem. However, its association with hypertensive disorders of pregnancy (HDP) is inconclusive.

OBJECTIVE

To find the association between smoking during pregnancy and HDP.

SEARCH STRATEGY

We searched PubMed, Ovid and Cochrane Library up to March, 2021, using terms including "smoking" and "HDP".

SELECTION CRITERIA

Observational studies that assessed the relationship between smoking during pregnancy and HDP were included.

DATA COLLECTION AND ANALYSIS

Odds ratios (OR) and 95% confidence intervals (CI), and other necessary data were extracted. Stata16.0 MP was used to analyze statistics.

MAIN RESULTS

A total of 13 studies were included. Meta-analysis revealed that smoking during pregnancy was a protective factor for HDP (OR 0.78, 95% CI 0.67-0.92), gestational hypertension (OR 0.74, 95% CI 0.69-0.79), and pre-eclampsia (OR 0.65, 95% CI 0.58-0.73). Subgroup analysis showed that smoking during pregnancy was a risk factor for HDP in Asia but a protective factor in Europe and North America. Neither quitting smoking before pregnancy nor during pregnancy had a statistically significant association with HDP.

CONCLUSION

This meta-analysis revealed that smoking during pregnancy might prevent HDP, gestational hypertension, and pre-eclampsia. Smoking during pregnancy was a risk factor for HDP in Asia but a protective factor in Europe and North America.

Factors Associated with Increased Risk of Early Severe Neonatal Morbidity in Late Preterm and Early Term Infants

Although the risk of neonatal mortality is generally low for late preterm and early term infants, they are still significantly predisposed to severe neonatal morbidity (SNM) despite being born at relatively advanced gestations. In this study, we investigated maternal and intrapartum risk factors for early SNM in late preterm and early term infants. This was a retrospective cohort study of non-anomalous, singleton infants (34⁺⁰-38⁺⁶ gestational weeks) born at the Mater Mother's Hospital in Brisbane, Australia from January 2015 to May 2020. Early SNM was defined as a composite of any of the following severe neonatal outcome indicators: admission to neonatal intensive care unit (NICU) in conjunction with an Apgar score <4 at 5 min, severe respiratory distress, severe neonatal acidosis (cord pH < 7.0 or base excess <-12 mmol/L). Multivariable binomial logistic regression analyses using generalized estimating equations (GEE) were used to identify risk factors. Of the total infants born at 34⁺⁰-38⁺⁶ gestational weeks, 5.7% had at least one component of the composite outcome. For late preterm infants, pre-existing diabetes mellitus, instrumental birth and emergency caesarean birth for non-reassuring fetal status were associated with increased odds for early SNM, whilst for early term infants, pre-existing and gestational diabetes mellitus, antepartum hemorrhage, instrumental, emergency caesarean and elective caesarean birth were significant risk factors. In conclusion, we identified several risk factors contributing to early SNM in late preterm and early term cohort. Our results suggest that predicted probability of early SNM decreased as gestation increased.

Motivos associados à interrupção do aleitamento materno exclusivo até seis meses de idade em lactentes acompanhados em Estratégias de Saúde da Família da cidade de Registro, São Paulo

Objetivo: Identificar os motivos associados à interrupção do aleitamento materno exclusivo entre nutrizes durante os primeiros seis meses de vida do lactente. Métodos: Estudo exploratório, descritivo, transversal, com abordagem quantitativa, conduzido com 911 mães/responsáveis de crianças de zero a 23 meses. Foram coletadas informações sociodemográficas e relato dos motivos que levaram a interrupção do aleitamento materno exclusivo antes dos seis meses de idade do lactente. Resultados: As participantes do estudo eram predominantemente brancas, com companheiro, com ensino médio, sem vínculo empregatício, com dois a quatro filhos, com renda familiar ≤ 1 salário mínimo, com moradia própria, na faixa etária ≥ 20 anos. Em sua maioria, as mães/responsáveis relataram ter recebido orientações sobre a alimentação de seu filho com maior frequência realizada pelo enfermeiro e 28,5% afirmaram ter interrompido o aleitamento materno exclusivo antes dos seis meses de vida do lactente. Possuir moradia própria, usar de tabaco e álcool foram associados à interrupção do aleitamento materno exclusivo. Os motivos que predominaram na interrupção do aleitamento materno exclusivo estiveram ligados principalmente ao relato de leite materno insuficiente, retorno ao trabalho/escola e recusa inexplicada. Conclusão: Os motivos para abandono do aleitamento materno exclusivo identificado neste estudo foram desde o relato de choro da criança à alegação de leite materno insuficiente. A identificação dos motivos que levam ao desmame precoce pode auxiliar no planejamento de estratégias para evitar a interrupção do aleitamento materno.

Maternal Smoking and Hospital Treatment During Pregnancy

INTRODUCTION

Previous research suggests that young maternal age, smoking, hospitalization during a previous pregnancy, and poor self-rated health could be risk factors for prenatal hospitalization.

METHODS

The objective of this retrospective observational register study was to investigate if maternal smoking during pregnancy is associated with mother's need for hospital treatment during pregnancy. The study population consists of all singleton pregnancies (n = 961 127) in 1999-2015 in Finland. Information on maternal smoking was received from the Medical Birth Register in three classes: nonsmoker, quit smoking in the first trimester, and continued smoking throughout the pregnancy. These data were linked with the Hospital Discharge Register data and analyzed according to ICD-10 chapters.

RESULTS

10.7% of women continued to smoke after the first trimester. After adjusting for confounding factors women in both smoking groups had more hospital treatment compared with nonsmokers. Especially outpatient treatment was more common among mothers who continued to smoke compared to those who quit smoking in the first trimester in several ICD-10 chapters. Compared to non-smokers, aOR for mental and behavioral disorders (F00-F99) was 2.14 (95% confidence interval 2.00-2.30) in the quit smoking group and 3.88 (3.71-4.06) in the continued smoking group. Similarly, aOR for respiratory diseases (J00-J99) was 1.26 (1.15-1.39) and 1.61 (1.52-1.71), respectively and aOR for genitourinary diseases (N00-N99) was 1.10 (1.03-1.17) and 1.29 (1.23-1.35), respectively. Some similar findings were made also in inpatient care. Some similar findings were made also in inpatient care.

CONCLUSIONS

Women who smoke during pregnancy seem to require more hospital care for various reasons. These findings emphasize the importance of actions for smoking cessation during pregnancy and women should be encouraged to quit as early as possible.

IMPLICATIONS

Maternal smoking during pregnancy is associated with greater rates of both outpatient and inpatient hospital care during pregnancy. Women who quit smoking had a similar risk for hospital care during pregnancy with nonsmokers in certain diagnosis chapters, which is very motivational and could be used as an informational tool in prenatal clinics to encourage smoking cessation as it is never too late to quit smoking during pregnancy.

Maternal body mass index, smoking status and small for gestational age: an Australian retrospective cohort study

OBJECTIVES

Both maternal body mass index (BMI) and smoking during pregnancy have been associated with a range of adverse maternal and infant birth outcomes. This study aimed to identify whether these independent variables had an interacting relationship with small for gestational age in an Australian obstetric cohort.

STUDY DESIGN

A retrospective cohort design used data from the Birthing Outcomes System of a major tertiary hospital in Australia.

METHODS

A total of 14,487 singleton births between January 2008 and December 2013 were included in the analysis. Chi-squared tests and one-way analysis of variance were used for the comparison of categorical and continuous variables, respectively. Adjusted odds ratios (AORs) were calculated to determine the association of smoking status with the outcome variable of interest, and these are reported for each maternal BMI category.

RESULTS

Of the 14,487 women, 716 (4.9%) were underweight (BMI ≤18 kg/m²), 7268 (50.2%) had healthy weight (BMI = 19-24 kg/m²), 3658 (25.3%) were overweight (BMI = 25-29 kg/m²), 1558 (10.8%) had class I obesity (BMI = 30-34 kg/m²), 711 (4.9%) had class II obesity (BMI = 35-39 kg/m²) and 576 (3.9%) had class III obesity (BMI = 40+ kg/m²). Of all women, 10.8% reported being current smokers, 82.0% reported to have never smoked and 4.0% reported to have stopped smoking during or before pregnancy. Smokers with a BMI ≥40 kg/m² were 4.5 (AOR = 4.508; 95% confidence interval: 2.068-9.828) times more likely to give birth to a small-for-gestational-age infant than non-smokers within the same BMI category. This increased risk was not observed in women who ceased smoking before or during pregnancy.

CONCLUSIONS

Our study supports the efficacy of antismoking policies within maternal public health. In addition, greater support with respect to smoking cessation is indicated for women during pregnancy with an elevated BMI.

Epidural analgesia during birth and adverse neonatal outcomes: A population-based cohort study

BACKGROUND

In general, epidural analgesia is considered a safe and efficient way to relieve pain during active labour and is increasingly used in childbirth. It is well documented that epidural analgesia during birth has benefits but also adverse effects. However, evidence is limited on how epidural analgesia influences neonatal outcome in a low-risk population of birthing women.

AIM

To examine low Apgar score, foetal hypoxia and admission to the neonatal intensive care unit in neonates of low-risk women receiving epidural analgesia during birth.

METHODS

A cohort study using registry data to investigate a population of 23,272 low-risk women giving birth at a university hospital.

RESULTS

Epidural analgesia was used in 21.6% of low-risk women during birth. Low Apgar score, foetal hypoxia, and admission to the neonatal intensive care unit were found in 0.6%, 0.6%, and 10.0%, respectively in neonates of mothers receiving epidural analgesia during birth compared to 0.3%, 0.6%, and 5.6%, respectively in the non-exposed group. Epidural analgesia was associated with low Apgar score, adjusted odds ratio 1.76 (95% CI 1.07-2.90) and admission to the neonatal intensive care unit, adjusted odds ratio 1.43 (95% CI 1.26-1.62). A mediation analysis indicates the impact of epidural analgesia on adverse neonatal outcomes was mediated by obstetric complications like maternal fever, labour augmentation, and foetal malpresentation.

CONCLUSION

This study found use of epidural analgesia during birth in low-risk pregnant women was associated with infant low Apgar score and admission to the neonatal intensive care unit.

Maternal smoking as an independent risk factor for the development of severe retinopathy of prematurity in very preterm infants

BACKGROUND/OBJECTIVES

Retinopathy of prematurity (ROP) is a severe neonatal complication potentially leading to visual impairment and blindness. Known risk factors include preterm birth, low birth weight and respiratory support. Limited and contradictory data exist on the risk of maternal smoking during pregnancy on the development of ROP. This study aims to investigate smoking as an independent risk factor for the development of severe ROP (≥stage 3).

SUBJECTS/METHODS

This is a single centre retrospective case-control study of prospectively collected clinical data of infants born before 32 weeks of gestation between 2001 and 2012 at a tertiary care university hospital. The association between maternal smoking during pregnancy and the development of severe ROP was analyzed by multivariate logistic regression.

RESULTS

In total, n = 751 infants born < 32 weeks of gestation were included in this study. In total, 52.9% (n = 397) were diagnosed with ROP and 10.8% (n = 81) developed ROP ≥ stage 3. In total, 8.4% (n = 63) mothers presented with a history of smoking during pregnancy, which was associated to a higher rate of ROP (OR 2.59, 95% CI 1.10-6.12). Low gestational age, low birth weight and prolonged respiratory support were confirmed as independent risk factors for the development of severe ROP.

CONCLUSIONS

To date, this is the largest study evaluating the effect of maternal smoking on the development of ROP. Maternal smoking during pregnancy is identified as an independent risk factor for the development of severe ROP in preterm infants born < 32 weeks of gestation.

Higher prevalence of hypertensive disorders of pregnancy in women who smoke: the Japan environment and children's study

Smoking during pregnancy is a risk factor for various adverse birth outcomes but lowers the risk of preeclampsia. Cardiovascular adaptations might underlie these associations. We examined the association of maternal smoking with the risk of hypertensive disorders of pregnancy (HDP) in a low-risk population-based cohort of 76,303 pregnant women. This study was a part of the Japan Environment and Children's Study. Smoking status was assessed using questionnaires completed by participants. Information about HDP was assessed using questionnaires completed by doctors. Compared with that for women who did not smoke, women who continued smoking >10 cigarettes per day during pregnancy had a significantly higher risk of developing HDP (odds ratio: 1.58, 95% confidence interval: 1.11-2.25). In multivariate analyses with adjustment for possible confounding factors, the association still remained (odds ratio: 1.51, 95% confidence interval: 1.04-2.19). When we regarded the number of cigarettes as a continuous variable, there was a linear association between the number of cigarettes and risk of HDP, with an odds ratio of 1.02 per cigarette per day (95% confidence interval: 1.00-1.04). Smoking a greater number of cigarettes was associated with a higher risk of HDP after adjustment for possible confounding factors. Cigarette smoking cessation may avoid the complications of HDP. Our findings suggest that, in addition to the risk of small-for-gestational-age children, an increased risk of HDP should be considered in the management of pregnant women who smoke cigarettes.

Maternal demographic and intrapartum antecedents of severe neonatal outcomes at term

Objective: To determine key demographic and intrapartum antecedents predisposing to severe adverse neonatal outcome at term.Methods: This was a retrospective cohort study of severe adverse neonatal outcomes of nonanomalous singleton term births at an Australian tertiary maternity unit between January 2007 and April 2017. Serious neonatal outcome (SNO) was defined as any of the following: Apgar score ≤3 at 5 min, severe respiratory distress syndrome, severe acidosis, admission into neonatal intensive care unit (NICU), stillbirth, or neonatal death. Multivariable generalized estimating equations were used to identify key demographic and intrapartum risk factors predisposing to poor neonatal outcomes.Results: There were 77 888 births with SNO occurring in 7247 (9.3%) cases. Young maternal age, raised BMI, indigenous ethnicity, nulliparity, smoking, illicit drug use, and diabetes mellitus were more common in the SANO cohort. Instrumental birth (aOR 3.24, 95%CI 3.02-3.47, p < .001), emergency cesarean section (aOR 1.61, 95%CI 1.49-1.73, p < .001), emergency cesarean for nonreassuring fetal status (aOR 3.45, 95%CI 3.04-3.92, p < .001), cord accidents (aOR 4.98, 95%CI 2.81-8.83, p < .001) and intrapartum hemorrhage (aOR 1.42, 95%CI 1.08-1.87, p = .01) were major antecedents. Induction of labor (aOR 1.08, 95%CI 1.01-1.15, p = .03), prolonged second stage (aOR 1.76, 95%CI 1.55-2.00, p < .001) and use of intramuscular opioids/narcotics (aOR 1.41, 95%CI 1.30-1.52, p < .001) were also associated with adverse neonatal outcome. Low birth weight (< 5th and <10th centiles) and macrosomia (> 90th and >95th centiles) and delivery at 37 weeks and >41 weeks were additional risk factors.Conclusion: There are multiple maternal and intrapartum risk factors which can predispose to severe outcomes in the neonate.

The burden of adverse obstetric and perinatal outcomes from maternal smoking in an Australian cohort

BACKGROUND

Maternal smoking is associated with a number of adverse outcomes with a dose-dependent increase in risk. The aim of this study was to evaluate the obstetric and perinatal outcomes in women who smoked during pregnancy.

METHODS

This was a retrospective cohort study of women who smoked during pregnancy and birthed at a major perinatal centre in Australia between January 2000 and April 2017. The study cohort was compared to a cohort of women who did not smoke in pregnancy. Smoking status was ascertained on history and included all types of smoking. Demographic characteristics and obstetric, intrapartum and perinatal outcomes were compared between the two groups.

RESULTS

The study cohort included 20 477 (14.6%) women who smoked during pregnancy and 119 396 controls. Women who smoked tended to be younger, of higher body mass index (BMI), Caucasian and Indigenous ethnicity. Smokers were less likely to be nulliparous, but more likely to be hypertensive and have a lower socioeconomic status compared to non-smokers. Women who smoked were more likely to have a caesarean section for non-reassuring fetal status (adjusted odds ratio (aOR) 1.16, 95%CI 1.07-1.26, P < 0.001). The infants of women who smoked were more likely to be born preterm, have a lower median birth weight and birth weights <10th (aOR 1.76, 95%CI 1.66-1.86, P < 0.001) and <5th centile (aOR 2.00, 95%CI 1.86-2.16, P < 0.001). Neonatal outcomes in the smoking cohort were worse with an increase in neonatal intensive care unit admission (aOR 1.34, 95%CI 1.27-1.43, P < 0.001), severe acidosis (aOR 1.41, 95%CI 1.27-1.43, P < 0.001) and a composite of severe neonatal outcomes (18.0% vs 12.0%, aOR 1.35, 95%CI 1.28-1.43, P < 0.001).

CONCLUSION

Women who smoke in pregnancy have worse obstetric and perinatal outcomes compared to controls and should be managed as high risk.

Impact of gestational nicotine exposure on intrauterine and fetal infection in a rodent model

We investigated the interaction between prenatal nicotine exposure and intrauterine infection using established rat models. Beginning at gestation day (GD) 6, dams were continuously infused with either saline or 6 mg/kg/day nicotine (Nic). At GD 14, dams received either sterile broth or 10⁵ colony-forming units Mycoplasma pulmonis (MP), resulting in four treatment groups: control (4 dams, 33 fetal units); MP only (5 dams, 55 fetal units); Nic only (5 dams, 61 fetal units), and Nic + MP (7 dams, 82 fetal units). At GD 18, nicotine exposure significantly increased (P ≤ 0.02) the percentage of amniotic fluids and fetuses infected by MP but did not impact colonization rates of maternal sites. Nicotine exposure significantly reduced the numbers of MP in the placenta required for high microbial loads (≥10⁴ color-changing units) in the amniotic fluid (P < 0.01). Fetal inflammatory response lesions were most extensive in the Nic only and Nic + MP groups (P < 0.0001). Control and MP only placentas were interleukin (IL)10-dominant, consistent with an M2/Th2 environment. Placentas exposed to nicotine shifted to a neutral environment, with equivalent levels of interferon gamma (IFNG) and IL10. Both IL6 and tumor necrosis factor (TNF) levels in amniotic fluid were highly elevated when both nicotine and infection were present. Our study suggests that prenatal exposure to nicotine increases the risk for intrauterine infection, lowers the infectious dose required to breach the placental barrier and infect the amniotic fluid and fetus, and alters the pathology and inflammatory profile associated with maternal and fetal sites.

Association between exposure to air pollution during pregnancy and false positives in fetal heart rate monitoring

Fetal heart rate (FHR) monitoring is essential for fetal management during pregnancy and delivery but results in many false-positive diagnoses. Air pollution affects the uterine environment; thus, air pollution may change FHR reactivity. This study assessed the association between exposure to air pollution during pregnancy and FHR monitoring abnormalities using 2005-2010 data from the Japan Perinatal Registry Network database. Participants were 23,782 singleton pregnant women with FHR monitoring, without acidemia or fetal asphyxia. We assessed exposure to air pollutants, including particulate matter (PM), ozone, nitrogen dioxide (NO2), and sulfur dioxide (SO2). In a multi-trimester model, first-trimester PM exposure was associated with false positives in FHR monitoring (odds ratio [OR] per interquartile range (10.7 μg/m3) increase = 1.20; 95% CI: 1.05-1.37), but not second-trimester exposure (OR = 1.05; 95% CI: 0.91-1.21) and third-trimester exposure (OR = 1.06; 95% CI: 0.96-1.17). The association with first-trimester PM exposure persisted after adjustment for exposure to ozone, NO2, and SO2; however, ozone, NO2, and SO2 exposure was not associated with false positives in FHR monitoring. First-trimester PM exposure may alter fetal cardiac response and lead to false positives in FHR monitoring.

Reducing tobacco smoking and smoke exposure to prevent preterm birth and its complications

Tobacco smoking and smoke exposure during pregnancy are associated with a range of adverse health outcomes, including preterm birth. Also, children born preterm have a higher risk of complications including bronchopulmonary dysplasia and asthma when their mothers smoked during pregnancy. Smoking cessation in early pregnancy can help reduce the adverse impact on offspring health. Counselling interventions are effective in promoting smoking cessation and reducing the incidence of preterm birth. Peer support and incentive-based approaches are likely to be of additional benefit, whereas the effectiveness of pharmacological interventions, including nicotine replacement therapy, has not definitely been established. Smoke-free legislation can help reduce smoke exposure as well as maternal smoking rates at a population level, and is associated with a reduction in preterm birth. Helping future mothers to stop smoking and protect their children from second hand smoke exposure must be a key priority for health care workers and policy makers alike.

Impact of risk factors for perinatal events in Japan: Introduction of a newly created perinatal event score

AIM

A cohort study was performed to clarify the influence of risk factors on perinatal events (obstetric complications and/or perinatal deaths).

METHODS

This cohort study reviewed 395 785 births from 2011 to 2013. Women with singleton pregnancies delivered after 22 weeks of gestation were included. The OR were determined on multivariate analysis. The perinatal event score (PES) for risk factors, which is the product of the OR of risk factors for obstetric complications, OR of risk factors for perinatal death, and OR of obstetric complications for perinatal death, was introduced to clarify the impact of each risk combination.

RESULTS

There were 20 risk factors such as maternal age and medical complications relating to the 11 obstetric complications, including pregnancy-induced hypertension and preterm labor. As a result, 77 combinations of risk factors and obstetric complications were found to be significant. Six obstetric complications such as preterm labor and cervical insufficiency were found to be related to perinatal death. Two factors were found to be directly related to perinatal death: age >40 years old (OR, 1.24; 95%CI: 1.11-1.39) and essential hypertension (OR, 1.56; 95%CI: 1.19-2.05). As a result, PES ranged from 1.07 (primipara for premature rupture of membrane) to 40.1 (essential hypertension for placental abruption), and high PES (≥8) was identified in 21 combinations of risk factors and obstetric complications.

CONCLUSION

This newly created score for perinatal events, PES, can be used as an indicator of the impact of risk factors on perinatal events.

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

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

The association between maternal smoking and placenta abruption: a meta-analysis

BACKGROUND

Several epidemiological studies have determined that maternal smoking can increase the risk of placenta abruption. To date, only a meta-analysis has been performed for assessing the relationship between smoking and placenta abruption. This meta-analysis was conducted to estimate the association between smoking and the risk of placenta abruption.

METHODS

A literature search was conducted in major databases such as PubMed, Web of Science, and Scopus from the earliest possible year to April 2016. The heterogeneity across studies was explored by Q-test and I² statistic. The publication bias was assessed using Begg's and Egger's tests. The results were reported using odds ratio (OR) estimate with its 95% confidence intervals (CI) using a random effects model.

RESULTS

The literature search yielded 1167 publications until April 2016 with 4 309 610 participants. Based on OR estimates obtained from case-control and cohort studies, there was a significant association between smoking and placenta abruption (1.80; 95% CI: 1.75, 1.85). Based on the results of cohort studies, smoking and placenta abruption had a significant association (relative risk ratio: 1.65; 95% CI: 1.51, 1.80).

CONCLUSIONS

Based on reports in epidemiological studies, we showed that smoking is a risk factor for placenta abruption.

Epidemiology of hypertensive disorders in pregnancy: prevalence, risk factors, predictors and prognosis

Hypertensive disorders in pregnancy (HDP) represent some of the most important problems faced by public health because HDP is a major cause of maternal and prenatal morbidity and mortality. Several epidemiological studies have been performed to determine the prevalence and risk factors of HDP as well as its subtypes. The prevalences of HDP, gestational hypertension and preeclampsia are 5.2-8.2%, 1.8-4.4% and 0.2-9.2%, respectively. Body mass index, anemia and lower education appear to be modifiable risk factors for HDP. Maternal age, primiparous, multiple pregnancy, HDP in previous pregnancy, gestational diabetes mellitus, preexisting hypertension, preexisting type 2 diabetes mellitus, preexisting urinary tract infection and a family history of hypertension, type 2 diabetes mellitus and preeclampsia appear to be nonmodifiable risk factors. Genetic variants including a single-nucleotide polymorphism in the angiotensinogen gene have also been reported to be nonmodifiable risk factors. Epidemiological studies have recently examined the associations between a history of HDP and its subtypes and future risks of other diseases. These studies have reported associations between a history of HDP and a risk of coronary heart disease, heart failure, dysrhythmia, stroke, hypertension, diabetes mellitus, end-stage renal dysfunction and cardiomyopathy. HDP is not associated with the future incidence of total cancer. In conclusion, HDP is not a rare complication of pregnancy and the influence of HDP remains for an extended duration. Physicians should consider the effects of HDP when treating chronic diseases in women.

Association Between Maternal Smoking During Pregnancy and Birth Weight: An Appropriately Adjusted Model From the Japan Environment and Children's Study

Background

There has been no large nationwide population-based study to examine the effects of maternal smoking status during pregnancy on birth weight that simultaneously controlled for clinical information, socioeconomic status, and maternal weight. Thus, this study aimed to determine the association between maternal smoking status during pregnancy and birth weight, while taking these confounding factors into consideration.

Methods

This study examined the first-year fixed dataset from a large nationwide birth cohort study that commenced in 2011. The dataset consisted of information on 9369 singleton infants born before December 31, 2011. Children were divided into 4 groups for statistical analysis: those born to mothers who did not smoke (NS), who quit smoking before pregnancy, who quit smoking during early pregnancy, and who smoked (SM). Multiple linear regression models were conducted for each sex to examine the association between maternal smoking status during early pregnancy and fetal growth. Birth weight was estimated using the least-squares method after controlling for covariates.

Results

After controlling for potential confounding factors, maternal smoking status during pregnancy was significantly associated with birth weight. There was a significant difference in birth weight between NS and SM for both male and female infants (male infants, 3096.2 g [NS] vs 2959.8 g [SM], P < 0.001; female infants, 3018.2 g [NS] vs 2893.7 g [SM], P < 0.001).

Conclusions

Using data from a large nationwide birth cohort study in Japan, we have shown that maternal smoking during pregnancy may reduce birth weight by 125–136 g.

Knowledge and attitudes of adults towards smoking in pregnancy: results from the HealthStyles© 2008 survey

Smoking during pregnancy is causally associated with many adverse health outcomes. Quitting smoking, even late in pregnancy, improves some outcomes. Among adults in general and reproductive-aged women, we sought to understand knowledge and attitudes towards prenatal smoking and its effects on pregnancy outcomes. Using data from the 2008 HealthStyles© survey, we assessed knowledge and attitudes about prenatal smoking and smoking cessation. We classified respondents as having high knowledge if they gave ≥ 5 correct responses to six knowledge questions regarding the health effects of prenatal smoking. We calculated frequencies of correct responses to assess knowledge about prenatal smoking and estimated relative risk to examine knowledge by demographic and lifestyle factors. Only 15 % of all respondents and 23 % of reproductive-aged women had high knowledge of the adverse effects of prenatal smoking on pregnancy outcomes. Preterm birth and low birth weight were most often recognized as adverse outcomes associated with prenatal smoking. Nearly 70 % of reproductive-aged women smokers reported they would quit smoking if they became pregnant without any specific reasons from their doctor. Few respondents recognized the benefits of quitting smoking after the first trimester of pregnancy. Our results suggest that many women lack knowledge regarding the increased risks for adverse outcomes associated with prenatal smoking. Healthcare providers should follow the recommendations provided by the American Congress of Obstetricians and Gynecologists, which include educating women about the health risks of prenatal smoking and the benefits of quitting. Healthcare providers should emphasize quitting smoking even after the first trimester of pregnancy.

The different effects of neighbourhood and individual social capital on health-compromising behaviours in women during pregnancy: a multi-level analysis

Background

This study assessed clustering of three health-compromising behaviours and explored the association of neighbourhood and individual social capital with simultaneous health-compromising behaviours and patterns of those behaviours in women in the first trimester of pregnancy (baseline) and during the second and third trimesters of pregnancy (follow-up).

Methods

A longitudinal study was conducted on a representative sample of women recruited in antenatal care units grouped in 46 neighbourhoods from Brazil. Neighbourhood-level measures (social capital and socioeconomic status), individual social capital (social support and social networks) and socio-demographic variables were collected at baseline. Smoking, alcohol consumption and inadequate diet were assessed at baseline and follow-up. Clustering was assessed using an observed to expected ratio method. The association of contextual and individual social capital with the health-compromising behaviours outcomes was analyzed through multilevel multivariate regression models.

Results

Clustering of the three health-compromising behaviours as well as of smoking and alcohol consumption were identified at both baseline and follow-up periods. Neighbourhood social capital did not influence the occurrence of simultaneous health-compromising behaviours. More health-compromising behaviours in both periods was inversely associated with low levels of individual social capital. Low individual social capital predicted smoking during whole pregnancy, while high individual social capital increased the likelihood of stopping smoking and improving diet during pregnancy. Maintaining an inadequate diet during pregnancy was influenced by low individual and neighbourhood social capital.

Conclusions

Three health-compromising behaviours are relatively common and cluster in Brazilian women throughout pregnancy. Low individual social capital significantly predicted simultaneous health-compromising behaviours and patterns of smoking and inadequate diet during pregnancy while low neighbourhood social capital was only relevant for inadequate diet. These findings suggest that interventions focusing on reducing multiple behaviours should be part of antenatal care throughout pregnancy. Individual and contextual social resources should be considered when planning the interventions.

Smoking cessation in pregnancy: psychosocial interventions and patient-focused perspectives

BACKGROUND

Smoking during pregnancy causes obstetric and fetal complications, and smoking cessation may have great benefits for the mother and the child. However, some pregnant women continue smoking even in pregnancy.

OBJECTIVE

To review the literature addressing the prevalence of smoking during pregnancy, explore psychosocial factors associated with smoking, and review the evidence of psychosocial interventions for smoking cessation during pregnancy in recent years.

LITERATURE REVIEW

Computerized Internet search results in PubMed for the years spanning from 2004 to 2014, as well as references cited in articles, were reviewed. A search for the keywords "smoking cessation pregnancy" and "intervention" and "clinical trials" yielded 52 citations. Thirty-five citations were identified as useful to this review for the evidence of psychosocial interventions for smoking cessation during pregnancy.

RESULTS

The prevalence of smoking during pregnancy differs by country, reflecting the countries' social, cultural, and ethnic backgrounds. Women who had socioeconomic disadvantages, problems in their interpersonal relationships, higher stress, depression, less social support, and who engaged in health-risk behaviors were more prone to smoking during pregnancy. Psychosocial interventions, such as counseling, are effective methods for increasing smoking cessation.

CONCLUSION

Smokers may have various psychosocial problems in addition to health problems. It is important to understand each individual's social situation or psychosocial characteristics, and a psychosocial intervention focused on the characteristics of the individual is required.

Analysis of case-cohort designs with binary outcomes: Improving efficiency using whole-cohort auxiliary information

The case-cohort design has been widely adopted for reducing the cost of covariate measurements in large prospective cohort studies. Under the case-cohort design, complete covariate data are collected only on randomly sampled cases and a subcohort randomly selected from the whole cohort. For the analysis of case-cohort studies with binary outcomes, logistic regression analysis has been routinely used. However, in many applications, certain covariates are readily measured on all samples from the whole cohort, and the case-cohort design may be regarded as a two-phase sampling design. Using this auxiliary covariate information, estimators for the regression parameters can be substantially improved. In this article, we discuss the theoretical basis of the case-cohort design derived from the formulation of the two-phase design and the improved estimators using whole-cohort auxiliary variable information. In particular, we show that the sampling scheme of the case-cohort design is substantially equivalent to that of conventional two-phase case-control studies (also known as two-stage case-control studies for epidemiologists), i.e., the methodologies of two-phase case-control studies can be directly applied to case-cohort data. Under this framework, we review and apply the following improved estimators to the case-cohort design with binary outcomes: (i) weighted estimators, (ii) a semiparametric maximum likelihood estimator, and (iii) a multiple imputation estimator. In addition, based on the framework of the two-phase design, we can obtain risk ratio and risk difference estimators without the rare-disease assumption. We illustrate these methodologies via simulations and the National Wilms Tumor Study data.

Association between smoking cessation interventions during prenatal care and postpartum relapse: results from 2004 to 2008 multi-state PRAMS data

Cigarette smoking is a serious global public health issue, and is particularly harmful to the maternal and child population. The study aimed to determine if there was an association between smoking cessation intervention during pregnancy and postpartum smoking relapse, and to define a time trend of postpartum smoking relapse after delivery. Data from the 2004-2008 pregnancy risk assessment monitoring systems of Colorado, Maine, Ohio, and Washington were analyzed. Logistic regression was used to define the association between smoking cessation intervention and postpartum smoking relapse, and to identify trend of postpartum smoking relapse. Analyses were done using SAS-Callable SUDAAN v.10.0 and Mplus v.6.0. Among the 2,938 women in the study the relapse rate was 48 %. It was 45 % among those without intervention, 58 % among those who received only counseling, and 57 % among those who received both counseling with treatment and/or referral. The rate was 42, 61, and 67 % among women whose infants were at 2-3, 4-5, and 6 months or more, respectively. Adjusted logistic regression models showed a trend of increased smoking relapse, but did not indicate an association between smoking cessation intervention and smoking relapse. Rates of smoking relapse were high and increased by time after delivery. Smoking cessation intervention during pregnancy may not be successful at preventing postpartum smoking relapse.

The many faces of tobacco use among women

Smoking is still considered to be mainly a male problem. However, it is estimated that there are approximately 250 million women worldwide who smoke cigarettes and millions more women who use smokeless tobacco products. This article addresses the many facets of tobacco use among women. The aim of the paper is to increase recognition among clinicians and researchers of the specific characteristics of female tobacco use. Together with providing epidemiological data on the distribution of tobacco use among women and data from population-based analyses on sociocultural factors that influence it, the article presents tobacco use during pregnancy as a particularly important public health problem. Further, the article points out sex-related differences (ie, physiological, psychological, or behavioral) between male and female tobacco use. A special focus is on the important role of ovarian hormones. Adverse effects of tobacco use to women and their children as well as tobacco-related morbidities and comorbidities are presented, and women's greater susceptibility to tobacco constituents as compared to men is stressed. Awareness of these differences can contribute to improvement of the effectiveness of smoking cessation programs addressed both to the specific female population and to an individual smoking woman.

Self-reported maternal cigarette smoke exposure during the periconceptional period and the risk for omphalocoele

BACKGROUND

We investigated whether maternal exposure to cigarette smoke was associated with omphalocoele and whether periconceptional folic acid modified the association.

METHODS

 : We analysed data from the National Birth Defects Prevention Study on omphalocoele case (n = 301) and control (n = 8135) mothers for infants born from 1997 through 2007. Mothers who reported active smoking or exposure to second-hand smoke during the periconceptional period (1 month before conception to 3 months after) were considered exposed. Those who reported use of folic acid supplements during the same period were considered supplement users. Odds ratios and 95% confidence intervals were estimated using multivariable logistic regression adjusted for alcohol use, preconception body mass index, and race/ethnicity.

RESULTS

One hundred fifteen (38.2%) case and 2592 (31.9%) control mothers reported exposure to cigarette smoke during the periconceptional period. Adjusted odds ratios [95% confidence intervals] were 1.19 [0.94, 1.53] for any smoke exposure, 0.87 [0.54, 1.40] for active smoking, 1.38 [1.00, 1.90] for second-hand smoke exposure, and 1.16 [0.80, 1.67] for both exposures combined. No dose-response relationship was observed. Folic acid-containing supplements did not reduce the risk for omphalocoele among women with active or second-hand smoke exposure.

CONCLUSIONS

Self-reported active maternal smoking, with or without exposure to second-hand smoke, during the periconceptional period was not associated with omphalocoele. In contrast, there was a possible association with periconceptional exposure to second-hand smoke.

Smoking and pregnancy--a review on the first major environmental risk factor of the unborn

Smoking cigarettes throughout pregnancy is one of the single most important avoidable causes of adverse pregnancy outcomes and it represents the first major environmental risk of the unborn. If compared with other risk factors in the perinatal period, exposure to tobacco smoke is considered to be amongst the most harmful and it is associated with high rates of long and short term morbidity and mortality for mother and child. A variety of adverse pregnancy outcomes are linked with cigarette consumption before and during pregnancy. Maternal prenatal cigarette smoke disturbs the equilibrium among the oxidant and antioxidant system, has negative impact on the genetic and cellular level of both mother and fetus and causes a large quantity of diseases in the unborn child. These smoking-induced damages for the unborn offspring manifest themselves at various times in life and for most only a very limited range of causal treatment exists. Education, support and assistance are of high importance to decrease maternal and fetal morbidity and mortality, as there are few other avoidable factors which influence a child's health that profoundly throughout its life. It is imperative that smoking control should be seen as a public health priority.

The independent effects of second hand smoke exposure and maternal body mass index on the anthropometric measurements of the newborn

Background

Exposure to tobacco smoke during pregnancy, whether as active smoking or by exposure to secondhand smoke (SHS), is associated with adverse pregnancy outcomes including low birth weight (LBW) and small for gestational age infants due to the effect of tobacco on the anthropometric measurements of the newborn. This effect might be masked by maternal obesity as it increases fetal weight. The objectives of this study were to estimate the independent effects of maternal exposure to SHS and maternal body mass index (BMI) on the anthropometric measurements and on the prevalence of macrosomia and LBW among term infants.

Methods

Data were collected from women in the postnatal ward following delivery. Participants were stratified into six groups based on the BMI (underweight <18 kg/m², non-obese 18–29.9 kg/m², and obese ≥30 kg/m²) and the SHS exposure status (exposed and non- exposed), to examine the independent effects of BMI and SHS on infants’ anthropometry. Multiple regression analysis was used to explore the independent associations between the six groups and the risk of delivering a macrosomic or LBW infant.

Results

Infants of women exposed to SHS had significantly reduced anthropometric measurements compared to infants of unexposed women. The odds of delivering a macrosomic baby increased to 9-fold for women with BMI of ≥30 kg/m² compared to non-obese women; odds ratio (OR) 9.18, 95% Confidence Interval (CI) (1.01, 9.37); p = 0.04, this risk was attenuated to 1.5-fold in women exposed to SHS, OR 1.53, 95% CI (1.19, 12.1); p < 0.0001. The odds of delivering an LBW infant were more than doubled in underweight women compared to non-obese women, OR 2.15, 95% CI (1.001, 4.57); p = 0.034, and were further increased to almost 3-fold for women who were exposed to SHS, OR 2.71, 95% CI (1.82,4.045); p = 0.02.

Conclusion

Exposure to SHS was associated with reduced anthropometric measurements of the newborn and increased rate of LBW infants, irrespective of maternal BMI. Maternal obesity was associated with increased risk of delivering a macrosomic infant; conversely maternal underweight was associated with increased risk of delivering an LBW infant.

Smoking habits in relation to reproductive events among Japanese women: findings of the Japanese Nurses' Health Study

OBJECTIVE

The purposes of this study were to examine smoking habits in relation to the reproductive events of pregnancy and menopause and clarify the reasons for smoking cessation among ex-smokers.

METHOD

This is a cross-sectional study based on a baseline survey of a prospective cohort study. From 2001 to 2007, a self-administered questionnaire survey was conducted on 49,927 female nurses from all 47 prefectures in Japan. Logistic regression models were used to estimate age-adjusted odds ratios.

RESULTS

Of the respondents, 17.2% were current smokers, 11.6% were ex-smokers and 69.8% had never smoked. The prevalence of smoking during pregnancy was 7.8%. Among ex-smokers, 30.3% gave "reproductive events" as their reason for smoking cessation. Current smoking and the number of cigarettes smoked per day before menopause were significantly related to onset of menopause.

CONCLUSION

Women's smoking habits have mutual relationships with reproductive events such as pregnancy and menopause. Although "reproductive events" were an important reason for smoking cessation among women, 7.8% of women still smoked during pregnancy. Smoking was correlated with onset of menopause. Support for smoking cessation is an important healthcare issue throughout women's lifetimes.

Population-based study of smoking behaviour throughout pregnancy and adverse perinatal outcomes

There has been limited research addressing whether behavioural change in relation to smoking is maintained throughout pregnancy and the effect on perinatal outcomes. A cohort study addressed lifestyle behaviours of 907 women who booked for antenatal care and delivered in a large urban teaching hospital in 2010-2011. Adverse perinatal outcomes were compared for "non-smokers", "ex-smokers" and "current smokers". Of the 907 women, 270 (30%) reported smoking in the six months prior to pregnancy, and of those 160 (59%) had stopped smoking and 110 (41%) continued to smoke at the time of the first antenatal visit. There was virtually no change in smoking behaviour between the first antenatal visit and the third trimester of pregnancy. Factors associated with continuing to smoke included unplanned pregnancy (OR 1.9; 95% CI 1.3, 2.9), alcohol use (OR 3.4; 95% CI 2.1, 6.0) and previous illicit drug use (OR 3.6; 95% CI 2.1, 6.0). Ex-smokers had similar perinatal outcomes to non-smokers. Current smoking was associated with an average reduction in birth weight of 191 g (95% CI -294, -88) and an increased incidence of intrauterine growth restriction (24% versus 13%, adjusted OR 1.39 (95% CI 1.06, 1.84). Public Health campaigns emphasise the health benefits of quitting smoking in pregnancy. The greatest success appears to be pre-pregnancy and during the first trimester where women are largely self-motivated to quit.

Effects of secondhand smoke on the birth weight of term infants and the demographic profile of Saudi exposed women

BACKGROUND

Maternal exposure to tobacco smoke during pregnancy is associated with detrimental effects on the mother and the fetus including; impaired fetal growth, low birth weight and preterm delivery. In utero exposure to tobacco is implicated in the etiology of many adults' diseases including obesity, diabetes and hypertension.The objectives of this study were to evaluate the effects of Secondhand Tobacco Smoke (SHS) exposure on newborns' anthropometric measurements and to compare the demographic profile of the women exposed to SHS to those who were not.

METHOD

This is a retrospective cohort study investigating the effects of SHS during pregnancy on newborns' anthropometry. Women who self-reported SHS exposure were compared with those not exposed. The primary outcomes were birth weight, newborn length and head circumference. Univariate analysis and multivariate regression analysis were performed. Adjusted differences with 95% confidence intervals were calculated.

RESULTS

Mothers exposed to SHS constituted 31% of the cohort. The mean birth weight of infants of exposed mothers was significantly lower by 35 g, 95% CI: 2-68 g, (P = 0.037) and the mean length was shorter by 0.261 cm, 95% CI 0.058-0.464 cm, (P = 0.012) compared to the infants of unexposed mothers. Women exposed to SHS, were younger, of lower parity and more likely to be illiterate than those who were not exposed in addition, exposed women were less likely to be primiparous.

CONCLUSION

The prevalence of exposure of Saudi pregnant women to SHS is high at 31% and it is associated with reduced birth weight, and shorter length of the newborn.

Labor induction and augmentation in women with multiple sclerosis

Background:

Fatigue and pelvic organ dysfunction are common among women with multiple sclerosis (MS), which may prolong labor and increase the risk of labor induction and/or augmentation.

Objective:

We set out to investigate the association between MS and related clinical factors (disease duration and the Expanded Disability Status Scale, EDSS) with labor induction/augmentation.

Methods:

Data from the British Columbia (BC) MS database were linked with the BC Perinatal Database Registry. Multivariable models were used to compare the likelihood of labor induction and augmentation between attempted vaginal deliveries (1998–2009) in women with MS ( n=381) and the general population ( n=2615).

Results:

In the MS cohort, 94/381 deliveries (25%) required labor induction and 147/381 deliveries (39%) required labor augmentation. Having MS was not associated with labor induction (adjusted odds ratio (OR)=0.91; 95% confidence interval (CI)=0.68–1.22, p=0.54) or augmentation (adjusted OR=0.91; 95% CI=0.72–1.15, p=0.43), but was associated with multiple methods of labor induction (OR=1.94; 95% CI=1.23–3.06, p=0.004). A higher EDSS score was associated with an increased risk of labor induction (adjusted p=0.04), but not labor augmentation (adjusted p > 0.5). Disease duration was not associated with either outcome (adjusted p > 0.2).

Conclusions:

Greater intervention may be required to initiate labor for women with a higher degree of disability due to MS.

Effects of maternal 5,10-methylenetetrahydrofolate reductase C677T and A1298C Polymorphisms and tobacco smoking on infant birth weight in a Japanese population

Background

Intracellular folate hemostasis depends on the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene. Because 5,10-MTHFR 677TT homozygosity and tobacco smoking are associated with low folate status, we tested the hypothesis that smoking in mothers with 5,10-MTHFR C677T or A1298C polymorphisms would be independently associated with lower birth weight among their offspring.

Methods

We assessed 1784 native Japanese mother-child pairs drawn from the ongoing birth cohort of The Hokkaido Study on Environment and Children’s Health. Data (demographic information, hospital birth records, and biological specimens) were extracted from recruitments that took place during the period from February 2003 to March 2006. Maternal serum folate were assayed by chemiluminescent immunoassay, and genotyping of 5,10-MTHFR C677T/A1298C polymorphisms was done using a TaqMan allelic discrimination assay.

Results

The prevalence of folate deficiency (<6.8 nmol/L) was 0.3%. The 5,10-MTHFR 677CT genotype was independently associated with an increase of 36.40 g (95% CI: 2.60 to 70.30, P = 0.035) in mean infant birth weight and an increase of 90.70 g (95% CI: 6.00 to 175.50, P = 0.036) among male infants of nonsmokers. Female infants of 677TT homozygous passive smokers were 99.00 g (95% CI: −190.26 to −7.56, P = 0.034) lighter. The birth weight of the offspring of smokers with 5,10-MTHFR 1298AA homozygosity was lower by 107.00 g (95% CI: −180.00 to −33.90, P = 0.004).

Conclusions

The results suggest that, in this population, maternal 5,10-MTHFR C677T polymorphism, but not the 5,10-MTHFR A1298C variant, is independently associated with improvement in infant birth weight, especially among nonsmokers. However, 5,10-MTHFR 1298AA might be associated with folate impairment and could interact with tobacco smoke to further decrease birth weight.

[The Fetal Tobacco Syndrome - A statement of the Austrian Societies for General- and Family Medicine (ÖGAM), Gynecology and Obstetrics (ÖGGG), Hygiene, Microbiology and Preventive Medicine (ÖGHMP), Pediatrics and Adolescence Medicine (ÖGKJ) as well as Pneumology (ÖGP)]

Over more than 50 years, the nocuous effects of smoking in pregnancy on the fetus are well known. In the first years of science the focus was primarily on restricted fetal growth while in more recent years over 10.000 studies investigated the incomparably big sum of detrimental effects for the unborn's health. In this statement we want to present the recent scientific findings on this topic. The statement is aimed to show all doctors who treat pregnant women the present situation and evidence. In the beginning we give a short overview about the epidemiological situation in Europe. Then we present step by step the health effects with regards to pathophysiology and clinics. Furthermore the reader will learn about possibilities for smoking cessation in pregnancy. The problem of passive-smoking in pregnancy will be dealt with in a separate chapter. At present there is strong evidence that pregnant smoking has a detrimental effect on birth-weight, placenta-associated disease, stillbirth, sudden infant death syndrome (SIDS), childhood overweight, clefts, lung function, asthma, cardiovascular diseases and mental developmental disorders. These factors can be summarized by the term Fetal Tobacco Syndrome. There is supply for more studies for less investigated health effects. Pregnancy is a chance to stop smoking as most women show a high motivation in this period. Hence doctors of all disciplines should inform pregnant women about the detrimental effects of smoking on their unborn child and show them possibilities for smoking cessation.