Maternal cigarette smoking and the risk of pregnancy-induced hypertension and eclampsia

Use of cigarettes and heated tobacco products during pregnancy and maternal-fetal outcomes: a retrospective, monocentric study

PURPOSE

To compare the effects of using heated tobacco products (HTP) or traditional cigarettes (C) on maternal and neonatal outcomes.

METHODS

This is a retrospective, monocentric study conducted at San Marco Hospital from July 2021 to July 2022. We compared a cohort of pregnant patients who smoked HTP (HS), with pregnant women smoking cigarettes (CS), ex-smoker (ES) and non-smoker (NS) pregnant women. Biochemistry, ultrasound, and neonatal evaluations were performed.

RESULTS

In total, 642 women were enrolled, of which 270 were NS, 114 were ES, 120 were CS, and 138 were HS. CS had the greatest weight gain and had more difficulty getting pregnant. Smokers and ES experienced more frequently threats of preterm labor, miscarriages, temporary hypertensive spikes, and higher rates of cesarean sections. Preterm delivery was more associated with CS and HS groups. CS and HS had lower awareness of the risks to which the mother and the fetus are exposed. CS were more likely to be depressed and anxious. Biochemical parameters did not show significant differences between the groups. CS had the greatest difference in days between the gestational age calculated based on the last menstrual period and the one based on the actual ultrasound age. The average percentile newborn weight range of CS was lower, as well as the mean 1st minute and the 5th minute Apgar scores.

CONCLUSION

The comparison of the data obtained between CS and HS underlines the greater danger of C. Nevertheless, we do not recommend HTP because the maternal-fetal outcomes are not superimposable to the NS outcomes.

Why Female Smokers Have Poorer Long-Term Health Outcomes than Male Smokers: The Role of Cigarette Smoking During Pregnancy

Objectives: Women's health status is better than men but the opposite is true for female smokers who usually have poorer long-health outcomes than male smokers. The objectives of this study were to thoroughly reviewed and analyzed relevant literature and to propose a hypothesis that may explain this paradox phenomenon. Methods: We conducted a search of literature from three English databases (EMBASE, MEDLINE, and Google Scholar) from inception to 13 November 2023. A combination of key words and/or subject headings in English was applied, including relevant terms for cigarette smoking, sex/gender, pregnancy, and health indicators. We then performed analysis of the searched literature. Results: Based on this review/analysis of literature, we proposed a hypothesis that may explain this paradox phenomenon: female smokers have worse long-term health outcomes than male smokers because some of them smoke during pregnancy, and the adverse effects of cigarette smoking during pregnancy is much stronger than cigarette smoking during non-pregnancy periods. Conclusion: Approval of our pregnancy-amplification theory could provide additional evidence on the adverse effect on women's long-term health outcomes for cigarette smoking during pregnancy.

Association of Gestational Hypertension with Sociodemographic and Anthropometric Factors, Perinatal Outcomes, Breastfeeding Practices, and Mediterranean Diet Adherence: A Cross-Sectional Study

Background and Objectives: Gestational hypertension has been associated with several pregnancy short-term and long-term complications, affecting both the mother and her infant's health. The present study aims to assess the potential association of gestational hypertension with sociodemographic and anthropometry factors, perinatal outcomes, breastfeeding habits, and Mediterranean diet (MD) compliance. Materials and Methods: This is a cross-sectional study conducted on 5271 mothers that was carried out after delivery. The anthropometry characteristics and perinatal outcomes were retrieved from the mothers' medical records. Sociodemographic characteristics, MD adherence, and breastfeeding habits were assessed via one-to-one interviews of the assigned women with qualified staff. Results: Maternal older age, being employed, family history of gestational hypertension, overweight/obesity before gestation, and abnormal gestational weight gain (GWG) independently increased the risk of developing gestational hypertension. Moreover, gestational hypertension was independently related with a greater incidence of abnormal childbirth body weight and preterm birth, not exclusively breastfeeding, and lower levels of MD adherence. Conclusions: This study highlights the importance of informing future mothers about the risk factors of gestational hypertension, underlining also that a healthy lifestyle, which simultaneously includes a healthy nutritional pattern such as MD, may decrease the risk of developing gestational hypertension and the subsequent pregnancy complications.

Soluble Vascular Adhesion Protein 1 (sVAP-1) as a biomarker for pregnancy complications: A pilot study

BACKGROUND

Vascular adhesion protein 1 (VAP-1) has been implicated in a wide range of clinical conditions. Moreover, serum levels are associated with disease prediction and progression in several clinical studies. There is a paucity of data on VAP-1 and pregnancy. Given the emerging role of VAP-1 in pregnancy, the aim of this study was to examine sVAP-1 as an early biomarker of pregnancy complications, especially hypertension during pregnancy. The objectives of the study are to associate sVAP-1 levels with other pregnancy complications, patient demographics and blood tests performed throughout pregnancy.

METHODS

We conducted a pilot study in a cohort of pregnant women (gestational week lower than 20 at the time of recruitment) attending their first antenatal ultrasound scan at the Leicester Royal Infirmary (LRI, UK). Data were both prospectively generated (from blood sample analysis) and retrospectively collected (from hospital records).

RESULTS

From July and October 2021, a total of 91 participants were enrolled. Using ELISA (enzyme-linked immunosorbent assay), we found reduced serum levels of sVAP-1 in pregnant women with either pregnancy induced hypertension (PIH) (310 ng/mL) or GDM (366.73 ng/mL) as compared to controls (427.44 ng/mL and 428.34 ng/mL, respectively). No significant difference was found between women with FGR compared to controls (424.32 ng/mL vs 424.52 ng/mL), and patients with any pregnancy complications compared to healthy pregnancies (421.28 ng/mL vs 428.34 ng/mL).

CONCLUSION

Further studies are needed to establish whether or not sVAP-1 might be considered as an early, non-invasive, and affordable biomarker to screen women who will develop PIH or GDM. Our data will aid sample size calculations for such larger studies.

Reevaluating the protective effect of smoking on preeclampsia risk through the lens of bias

Preeclampsia is a hypertensive disorder that is usually diagnosed after 20 weeks' gestation. Despite the deleterious effect of smoking on cardiovascular disease, it has been frequently reported that smoking has a protective effect on preeclampsia risk and biological explanations have been proposed. However, in this manuscript, we present multiple sources of bias that could explain this association. First, key concepts in epidemiology are reviewed: confounder, collider, and mediator. Then, we describe how eligibility criteria, losses of women potentially at risk, misclassification, or performing incorrect adjustments can create bias. We provide examples to show that strategies to control for confounders may fail when they are applied to variables that are not confounders. Finally, we outline potential approaches to manage this controversial effect. We conclude that there is probably no single epidemiological explanation for this counterintuitive association.

A global view of hypertensive disorders and diabetes mellitus during pregnancy

Two important maternal cardiometabolic disorders (CMDs), hypertensive disorders in pregnancy (HDP) (including pre-eclampsia) and gestational diabetes mellitus (GDM), result in a large disease burden for pregnant individuals worldwide. A global consensus has not been reached about the diagnostic criteria for HDP and GDM, making it challenging to assess differences in their disease burden between countries and areas. However, both diseases show an unevenly distributed disease burden for regions with a low income or middle income, or low-income and middle-income countries (LMICs), or regions with lower sociodemographic and human development indexes. In addition to many common clinical, demographic and behavioural risk factors, the development and clinical consequences of maternal CMDs are substantially influenced by the social determinants of health, such as systemic marginalization. Although progress has been occurring in the early screening and management of HDP and GDM, the accuracy and long-term effects of such screening and management programmes are still under investigation. In addition to pharmacological therapies and lifestyle modifications at the individual level, a multilevel approach in conjunction with multisector partnership should be adopted to tackle the public health issues and health inequity resulting from maternal CMDs. The current COVID-19 pandemic has disrupted health service delivery, with women with maternal CMDs being particularly vulnerable to this public health crisis.

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.

Pumps or Multiple Daily Injections in Pregnancy Involving Type 1 Diabetes: A Prespecified Analysis of the CONCEPTT Randomized Trial

OBJECTIVE

To compare glycemic control, quality of life, and pregnancy outcomes of women using insulin pumps and multiple daily injection therapy (MDI) during the Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT).

RESEARCH DESIGN AND METHODS

This was a prespecified analysis of CONCEPTT involving 248 pregnant women from 31 centers. Randomization was stratified for pump versus MDI and HbA_1c. The primary outcome was change in HbA_1c from randomization to 34 weeks' gestation. Key secondary outcomes were continuous glucose monitoring (CGM) measures, maternal-infant health, and patient-reported outcomes.

RESULTS

At baseline, pump users were more often in stable relationships (P = 0.003), more likely to take preconception vitamins (P = 0.03), and less likely to smoke (P = 0.02). Pump and MDI users had comparable first-trimester glycemia: HbA_1c 6.84 ± 0.71 vs. 6.95 ± 0.58% (51 ± 7.8 vs. 52 ± 6.3 mmol/mol) (P = 0.31) and CGM time in target (51 ± 14 vs. 50 ± 13%) (P = 0.40). At 34 weeks, MDI users had a greater decrease in HbA_1c (-0.55 ± 0.59 vs. -0.32 ± 0.65%, P = 0.001). At 24 and 34 weeks, MDI users were more likely to achieve target HbA_1c (P = 0.009 and P = 0.001, respectively). Pump users had more hypertensive disorders (P = 0.011), mainly driven by increased gestational hypertension (14.4 vs. 5.2%; P = 0.025), and more neonatal hypoglycemia (31.8 vs. 19.1%, P = 0.05) and neonatal intensive care unit (NICU) admissions >24 h (44.5 vs. 29.6%; P = 0.02). Pump users had a larger reduction in hypoglycemia-related anxiety (P = 0.05) but greater decline in health/well-being (P = 0.02).

CONCLUSIONS

In CONCEPTT, MDI users were more likely to have better glycemic outcomes and less likely to have gestational hypertension, neonatal hypoglycemia, and NICU admissions than pump users. These data suggest that implementation of insulin pump therapy is potentially suboptimal during pregnancy.

The Effect of Motivational Interviewing on Craving and Dependence on Hookah in Suburban Pregnant Women in South East of Iran

Hookah smoking during pregnancy is a health concern which requires effective interventions. Thus, the authors have aimed to evaluate the effect of motivational interviewing on craving and dependence on hookah in pregnant women (n = 140) addicted to hookah who reside in the outskirts of Zahedan, a city in southeast of Iran. The subjects were selected using the convenience sampling and randomly divided into either the control or intervention group. The intervention group received five motivational interviewing group sessions about hookah smoking withdrawal, whereas the control group was given the conventional recommendations for quitting hookah. Data were collected after 8 weeks during the post intervention period using Hookah Craving Test and Hookah Addiction Severity Index. Next, they were analyzed using independent t-test, paired t-test, and analysis of covariance (ANCOVA). After the motivational interviewing intervention, the independent t-test indicated a significant difference between the intervention and control groups in terms of the mean score of hookah craving (P = 0.0001). Moreover, ANCOVA, with control of the effect of pretest and duration of hookah addiction, demonstrated a significant difference between the two groups regarding the mean score of hookah dependence after the intervention (P = 0.0001). Motivational interviewing had a significant positive impact on decreased hookah craving and dependence (two indices of withdrawal). Therefore, healthcare providers are recommended to incorporate motivational interviewing-based education into prenatal care programs to promote the chance of hookah smoking withdrawal.

First-trimester smoking cessation in pregnancy did not increase the risk of preeclampsia/eclampsia: A Murmansk County Birth Registry study

Background

Although prior studies have shown that smoking reduces preeclampsia/eclampsia risk, the consequence of giving up this habit during pregnancy should be assessed. The aims of the current study were threefold: (i) describe maternal characteristics of women with preeclampsia/eclampsia; (ii) examine a possible association between the number of cigarettes smoked daily during pregnancy and the development of this affliction; and (iii) determine if first-trimester discontinuation of smoking during pregnancy influences the risk.

Methods

A registry-based study was conducted using data from the Murmansk County Birth Registry (MCBR). It included women without pre-existing hypertension, who delivered a singleton infant during 2006–2011 and had attended the first antenatal visit before 12 week of gestation. We adjusted for potential confounders using logistic regression.

Results

The prevalence of preeclampsia/eclampsia was 8.3% (95%CI: 8.0–8.6). Preeclampsia/eclampsia associated with maternal age, education, marital status, parity, excessive weight gain and body mass index at the first antenatal visit. There was a dose-response relationship between the number of smoked cigarettes per day during pregnancy and the risk of preeclampsia/eclampsia (adjusted OR_{1-5 cig/day} = 0.69 with 95%CI: 0.56–0.87; OR_{6-10 cig/day} = 0.65 with 95%CI: 0.51–0.82; and OR_{≥11 cig/day} = 0.49 with 95%CI: 0.30–0.81). There was no difference in this risk among women who smoked before and during pregnancy and those who did so before but not during pregnancy (adjusted OR = 1.10 with 95%CI: 0.91–1.32).

Conclusions

Preeclampsia/eclampsia was associated with maternal age, education, marital status, parity, excessive weight gain, and body mass index at the first antenatal visit. There was a negative dose-response relationship between the number of smoked cigarettes per day during pregnancy and the odds of preeclampsia/eclampsia. However, women who gave up smoking during the first trimester of gestation had the same risk of preeclampsia/eclampsia as those who smoked while pregnant. Consequently, antenatal clinic specialists are advised to take these various observations into account when counselling women on smoking cessation during pregnancy.

Heme Oxygenases in Cardiovascular Health and Disease

Heme oxygenases are composed of two isozymes, Hmox1 and Hmox2, that catalyze the degradation of heme to carbon monoxide (CO), ferrous iron, and biliverdin, the latter of which is subsequently converted to bilirubin. While initially considered to be waste products, CO and biliverdin/bilirubin have been shown over the last 20 years to modulate key cellular processes, such as inflammation, cell proliferation, and apoptosis, as well as antioxidant defense. This shift in paradigm has led to the importance of heme oxygenases and their products in cell physiology now being well accepted. The identification of the two human cases thus far of heme oxygenase deficiency and the generation of mice deficient in Hmox1 or Hmox2 have reiterated a role for these enzymes in both normal cell function and disease pathogenesis, especially in the context of cardiovascular disease. This review covers the current knowledge on the function of both Hmox1 and Hmox2 at both a cellular and tissue level in the cardiovascular system. Initially, the roles of heme oxygenases in vascular health and the regulation of processes central to vascular diseases are outlined, followed by an evaluation of the role(s) of Hmox1 and Hmox2 in various diseases such as atherosclerosis, intimal hyperplasia, myocardial infarction, and angiogenesis. Finally, the therapeutic potential of heme oxygenases and their products are examined in a cardiovascular disease context, with a focus on how the knowledge we have gained on these enzymes may be capitalized in future clinical studies.

Involvement of the Heme Oxygenase System in the Development of Preeclampsia and as a Possible Therapeutic Target

The enzyme heme oxygenase (HO) is an important regulatory molecule present in most nucleated mammalian cells which functions to break down the pro-oxidant molecule heme into three products, carbon monoxide (CO), biliverdin and free iron. The HO system has been associated with many physiologic functions, including vascular tone, regulation of inflammation and apoptosis, angiogenesis and antioxidant capabilities. Deficiencies in HO are associated with several pregnancy disorders, including preeclampsia. With no present cure, this disorder continues to affect 5–7% of all pregnancies worldwide, leading to maternal and fetal morbidity and mortality. Researchers continue to strive for therapeutic potentials and this review will outline the possible use of the HO/CO system as a target treatment/prevention of preeclampsia in the future.

Maternal exposure to the production of fireworks and reduced rate of new onset hypertension in pregnancy

BACKGROUND

Carbon monoxide (CO) is one of the main substances contained in fireworks. Previous studies suggested that CO may have protective effect on the development of hypertension of pregnancy.

METHOD

The authors conducted a prospective cohort study in Liuyang, Hunan, China between January 2010 and December 2011. Demographic and life-style variables of the participating pregnant women were obtained through structured interview with the women and clinical data were retrieved from antenatal medical records. Density of fireworks factories was defined as the number of fireworks factories per 1000 residents in the township where the mothers resided during pregnancy. Multiple logistic regression analysis was used to analyze the independent association between maternal exposure to the production of fireworks and new onset hypertension in pregnancy.

RESULTS

A total of 5976 pregnant women were included in the final analysis. Density of fireworks factories was inversely correlated with incidence of new onset hypertension in pregnancy (Pearson correlation coefficient = -0.29, p < 0.001). Multiple logistic regression analysis showed that, compared with women who resided during pregnancy in a township with 0-0.25 fireworks factories per 1000 residents, the rates of new onset hypertension in pregnancy in women who resided in a township with 0.26-1.00 fireworks factories per 1000 residents (Odds Ratio = 0.66, 95% confidence interval: 0.46, 0.96) and >1.5 fireworks factories per 1000 residents (Odds Ratio = 0.65, 95% confidence interval: 0.44, 0.97) were reduced by more than 30%.

CONCLUSION

Maternal exposure to the high density of fireworks factories is associated with reduced risk of developing new onset hypertension in pregnancy.

Maternal smoking during pregnancy and the risk of childhood type 1 diabetes in Western Australia

AIMS/HYPOTHESIS

The aim of this study was to investigate the association between maternal smoking during pregnancy and type 1 diabetes in the offspring, using complete population data sources available in Western Australia.

METHODS

A prospective cohort study was undertaken with cases defined as children born in Western Australia between 1998 and 2008 who were diagnosed with type 1 diabetes at <15 years of age up to 31 December 2010. Eligible cases were identified from the prospective, population-based Western Australian Children's Diabetes Database. Record linkage was performed to identify perinatal records of cases from the Western Australian Midwives' Notification System, which contains data on >99% of all births in Western Australia. Cox regression was used to analyse the data and adjust for recognised risk factors such as birthweight, gestational age, maternal age and socioeconomic status.

RESULTS

The unadjusted HR for babies born to mothers who smoked during pregnancy being diagnosed with childhood type 1 diabetes was 0.70 (95% CI: 0.50, 0.97). After adjustment, the confidence interval widened but the point estimate remained relatively unchanged at 0.76 (95% CI: 0.54, 1.08).

CONCLUSIONS/INTERPRETATION

Analyses of data from this population-based study indicate that maternal smoking during pregnancy may be associated with a reduced risk of childhood type 1 diabetes. Further investigation in larger populations with more detailed smoking data could lead to novel hypotheses regarding mechanisms that influence the immunopathogenesis of type 1 diabetes in early life.

Plasma cotinine indicates an increased risk of preeclampsia in previous and passive smokers

OBJECTIVE

Self-reported tobacco smoking in pregnancy has been consistently associated with a decreased risk of developing preeclampsia, but the evidence has been limited and inconsistent for previous and passive smokers. Misclassifications and inaccuracies of self-reported tobacco exposure may disguise the true relationship. This study aimed to assess the association of gestational hypertension and preeclampsia with maternal smoking status as ascertained by plasma cotinine.

STUDY DESIGN

This was a prospective study of 605 pregnant women without chronic hypertension. Maternal smoking status at 24-26 weeks' gestation was defined by plasma cotinine: >3.0 ng/mL "current smokers," 0.20-3.00 ng/mL "previous and passive smokers," and <0.20 ng/mL "nonsmokers."

RESULTS

Compared to nonsmokers, the risk of developing preeclampsia did not change significantly for current smokers, but increased significantly (adjusted odds ratio, 6.06; 95% confidence interval, 2.32-15.85; P < .001) for previous and passive smokers. There were no significant differences in the risk of developing gestational hypertension only.

CONCLUSION

Previous and passive smoking may increase the risk of preeclampsia. Avoidance of exposure to environmental tobacco smoke in pregnancy may decrease the risk of preeclampsia.

Chronic carbon monoxide inhalation during pregnancy augments uterine artery blood flow and uteroplacental vascular growth in mice

End-tidal breath carbon monoxide (CO) is abnormally low in women with preeclampsia (PE), while women smoking during pregnancy have shown an increase in CO levels and a 33% lower incidence of PE. This effect may be, in part, due to lowered sFLT1 plasma levels in smokers, and perhaps low-level CO inhalation can attenuate the development of PE in high-risk women. Our previous work showed maternal chronic CO exposure (<300 ppm) throughout gestation had no maternal or fetal deleterious effects in mice. Our current study evaluated the uteroplacental vascular effects in CD-1 maternal mice that inhaled CO (250 ppm) both chronically, gestation day (GD) 0.5 to 18.5, and acutely, 2.5 h on each of GD 10.5 and 14.5. We demonstrated, using microultrasound measurements of blood velocity and microcomputed tomography imaging of the uteroplacental vasculature, that chronic maternal exposure to CO doubled uterine artery blood flow and augmented uteroplacental vascular diameters and branching. This finding may be of benefit to women with PE, as they exhibit uteroplacental vascular compromise. The ratio of VEGF protein to its FLT1 receptor was increased in the placenta, suggesting a shift to a more angiogenic state; however, maternal circulating levels of VEGF, sFLT1, and their ratio were not significantly changed. Doppler blood velocities in the maternal uterine artery and fetal umbilical artery and vein were unaltered. This study provides in vivo evidence that chronic inhalation of 250 ppm CO throughout gestation augments uterine blood flow and uteroplacental vascular growth, changes that may protect against the subsequent development of preeclampsia.

Maternal exposure to moderate ambient carbon monoxide is associated with decreased risk of preeclampsia

OBJECTIVE

Carbon monoxide (CO) in cigarette smoke may be the mechanism by which tobacco use during pregnancy decreases the risk of the development of preeclampsia. We attempted to test this hypothesis by examining the effect of maternal exposure to ambient CO on preeclampsia.

STUDY DESIGN

Births that occurred between 2004 and 2009 in the Canadian province of Ontario were extracted from the data. Study subjects were divided into 4 groups according to quartiles of CO concentration that were based on maternal residence. Adjusted odds ratio and 95% confidence interval were used to estimate the independent effect of CO on preeclampsia.

RESULTS

Rates of preeclampsia were 2.32%, 1.97%, 1.59%, and 1.26%, respectively, in the first, second, third, and fourth quartile of CO concentration. The inverse association between CO concentration and preeclampsia risk remained the same after adjustment for several important confounding factors.

CONCLUSION

Maternal exposure to moderate ambient CO is associated independently with a decreased risk of preeclampsia.

Differences in gene expression between first and third trimester human placenta: a microarray study

BACKGROUND

The human placenta is a rapidly developing organ that undergoes structural and functional changes throughout the pregnancy. Our objectives were to investigate the differences in global gene expression profile, the expression of imprinted genes and the effect of smoking in first and third trimester normal human placentas.

MATERIALS AND METHODS

Placental samples were collected from 21 women with uncomplicated pregnancies delivered at term and 16 healthy women undergoing termination of pregnancy at 9-12 weeks gestation. Placental gene expression profile was evaluated by Human Genome Survey Microarray v.2.0 (Applied Biosystems) and real-time polymerase chain reaction.

RESULTS

Almost 25% of the genes spotted on the array (n = 7519) were differentially expressed between first and third trimester placentas. Genes regulating biological processes involved in cell proliferation, cell differentiation and angiogenesis were up-regulated in the first trimester; whereas cell surface receptor mediated signal transduction, G-protein mediated signalling, ion transport, neuronal activities and chemosensory perception were up-regulated in the third trimester. Pathway analysis showed that brain and placenta might share common developmental routes. Principal component analysis based on the expression of 17 imprinted genes showed a clear separation of first and third trimester placentas, indicating that epigenetic modifications occur throughout pregnancy. In smokers, a set of genes encoding oxidoreductases were differentially expressed in both trimesters.

CONCLUSIONS

Differences in global gene expression profile between first and third trimester human placenta reflect temporal changes in placental structure and function. Epigenetic rearrangements in the human placenta seem to occur across gestation, indicating the importance of environmental influence in the developing feto-placental unit.

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

BACKGROUND

The adverse effects of maternal smoking on the health of pregnant women have been examined mostly on a disease-by-disease basis. The aims of this study were to evaluate simultaneously the effects of smoking during pregnancy on various obstetric complications, using data from a large medical database, and to investigate the expediency of using a case-cohort design for such an analysis.

METHODS

A case-cohort study was conducted within the Japan Perinatal Registry Network database. Perinatal information on infant deliveries was entered into the database at 125 medical centers in Japan. The base population of the study was 180 855 pregnant women registered in the database from 2001 through 2005. The outcome measures were the incidences of 11 different obstetric complications. Logistic regression models were used to estimate age-adjusted risk ratios (aRRs) and relative excess incidence proportions (REIs).

RESULTS

The overall prevalence of smoking during pregnancy was 5.8% in the base cohort, and the prevalence was higher among younger women. A comparison of the cases and control cohort showed that smokers during pregnancy had statistically significant higher risks for preterm rupture of the membrane (aRR: 1.67, 95% confidence interval [CI]: 1.43-1.96; REI: 40.2%, 95% CI: 29.9%-49.1%), chorioamnionitis (1.65, 1.36-2.00; 39.4%, 26.4%-50.0%), incompetent cervix (1.63, 1.35-1.96; 38.5%, 25.8%-49.1%), threatened premature delivery (1.38, 1.17-1.64; 27.7%, 14.5%-38.9%), placental abruption (1.37, 1.10-1.72; 27.1%, 8.8%-41.7%), and pregnancy-induced hypertension (1.20, 1.01-1.41; 16.4%, 1.2%-29.3%).

CONCLUSIONS

Maternal smoking was associated with a number of obstetric complications. This highlights the importance of smoking cessation during pregnancy. In addition, case-cohort analysis proved useful in estimating RRs for multiple outcomes in a large database.

Prenatal tobacco exposure and cortisol levels in infants of teen mothers

AIMS

prenatal tobacco exposure (PTE) is an important public health concern for the offspring of teen mothers. We examined whether PTE is associated with baseline cortisol levels in four-month-old infants of teenage mothers.

METHODS

we assessed salivary cortisol levels of 212 infants. PTE was measured by using self-reports of cigarette smoking during pregnancy. We used a propensity scores matching analysis to compare infants with PTE and those without.

RESULTS

of 212 mothers, 151 smoked during pregnancy. However, there was no association between PTE and infant cortisol levels.

CONCLUSIONS

we could not support a relation between PTE and cortisol levels in a sample of four-month-old infants of teenage mothers.

Low birthweight and preterm birth rates 1 year before and after the Irish workplace smoking ban

OBJECTIVE

It is well-established that maternal smoking has adverse birth outcomes (low birthweight, LBW, and preterm births). The comprehensive Irish workplace smoking ban was successfully introduced in March 2004. We examined LBW and preterm birth rates 1 year before and after the workplace smoking ban in Dublin.

DESIGN

A cross-sectional observational study analysing routinely collected data using the Euroking K2 maternity system.

SETTING

Coombe University Maternal Hospital.

POPULATION

Only singleton live births were included for analyses (7593 and 7648, in 2003 and 2005, respectively).

METHODS

Detailed gestational and clinical characteristics were collected and analysed using multivariable logistic regression analyses and subgroup analyses.

MAIN OUTCOME MEASURES

Maternal smoking rates, mean birthweights, and adjusted odds ratios (ORs) of LBW and preterm births in 2005 versus 2003.

RESULTS

There was a 25% decreased risk of preterm births (OR, 0.75; 95% CI, 0.59-0.96), a 43% increased risk of LBW (OR, 1.43; 95% CI, 1.10-1.85), and a 12% fall in maternal smoking rates (from 23.4 to 20.6%) in 2005 relative to 2003. Such patterns were significantly maintained when specific subgroups were also analysed. Mean birthweights decreased in 2005, but were not significant (P=0.99). There was a marginal increase in smoking cessation before pregnancy in 2005 (P=0.047).

CONCLUSIONS

Significant declines in preterm births and in maternal smoking rates after the smoking ban are welcome signs. However, the increased LBW birth risks might reflect a secular trend, as observed in many industrialised nations, and merits further investigations.

Gestational diabetes and pre-eclampsia: common antecedents?

OBJECTIVE

To evaluate commonality of risk factor profiles of women who develop gestational diabetes and pre-eclampsia.

METHODS

Prospective cohort study in prenatal clinics of the Brazilian Unified Health System in six state capitals. 4.766 pregnant women between 20 to 48 years old were consecutively enrolled between 20th and 28th gestational weeks. Smoking habits and traditional risk factors for pre-eclampsia and gestational diabetes were obtained by the interview at enrollment. Gestational diabetes was diagnosed using a 75-g oral glucose tolerance test and pre-eclampsia through chart review.

RESULTS

Both gestational diabetes and pre-eclampsia were associated with age (OR 2.07; 95% CI 1.65-2.23 and OR 1.55; 95% CI 1.08-2.23, respectively), pre-pregnancy body mass index (OR 1.62; 95% CI 1.40-3.53 and OR 1.83; 95% CI 1.52-4.80, respectively) and weight gain in early pregnancy (OR 1.28; 95% CI 1.12-1.47 and OR 1.27; 95% CI 1.06-1.52, respectively). Lower odds of gestational diabetes (OR 0.31; 95% CI 0.22-0.44) and pre-eclampsia (OR 0.36; 95% CI 0.20-0.51) were observed in nulliparous women who have smoked during pregnancy.

CONCLUSIONS

Gestational diabetes and pre-eclampsia share a pattern of risk factors, suggesting the possibility of common aetiology.

Smoking in moderate/severe preeclampsia worsens pregnancy outcome, but smoking cessation limits the damage

We studied phenotypic and clinical outcome data in an observational, multicenter cohort study of 1001 Western European white women and their singleton babies, with stringently defined moderate-to-severe preeclampsia. Ninety women admitted to being current smokers; 71 had stopped smoking before entry to the study. Across the categories of never-smoker, stopped, and current smoker there were significant increases in the proportion of women delivering before 34 weeks' gestation (P=0.011), delivering a baby below the third birth weight centile (P<0.001), or delivering a baby with any adverse outcome (P=0.011). By comparison with never-smokers, smoking during pregnancy was associated with a doubling of risk of being delivered before 34 weeks' (odds ratio: 1.98; 95% CI: 1.24 to 3.16; P=0.004), of delivering babies below the third centile of corrected birth weight (odds ratio: 2.20; 95% CI 1.41 to 3.44; P<0.0001), or for their babies to have any adverse outcome (odds ratio: 1.87; 95% CI: 1.19 to 2.95; P<0.006). Worryingly, the risk of developing eclampsia was increased 5-fold (odds ratio: 4.88; 95% CI: 1.44 to 16.61; P=0.005). The proportion of smokers in these preeclamptic women was lower than in our pregnant population generally. However, preeclampsia still carries significant perinatal morbidity, and cigarette smoking in preeclamptic pregnancies exacerbates this. Stopping smoking decreases the risks. Smoking in young women should be a particular target for advice by general practitioners before pregnancy, with active encouragement after conception to enroll in such trials as the current Smoking, Nicotine and Pregnancy Trial to support cessation.

Smoking during pregnancy according to obstetric complications and parity: results of the EUROPOP study

This study aimed to analyse the relationship between smoking and preterm birth (22-36 weeks) according to the main obstetric complications leading to the preterm birth, both overall and by parity. The EUROPOP study is a case-control study carried out between 1994 and 1997; 3,787 preterm and 5,602 full-term births were included, from maternity units in 10 countries, using the same protocol. Social, demographic and medical information was collected after delivery, from obstetric records and interviews with the mothers. Cases were classified according to the main obstetric complication (hypertension, haemorrhage, preterm premature rupture of membranes (PPROM), idiopathic spontaneous preterm labour, intrauterine growth retardation, all other causes). Multiple logistic regression analysis was used to control for confounders. Twenty four percent of cases and 20% of controls were smokers. Smoking during pregnancy, heavy smoking (>or=10 cigarettes per day) in particular, was a risk factor for preterm birth (aOR = 1.39, 95% CI:1.20-1.60). Smoking increased the risk of preterm delivery due to all obstetric complications other than hypertension. For these complications, the risk of preterm delivery associated with smoking was higher for multiparae (aOR = 1.46, 95% CI:1.24-1.71) than for primiparae (aOR = 1.18, 95% CI:1.00-1.38). In conclusion, smoking during pregnancy increases the risk of preterm birth among women with all obstetric complications except hypertension. This association is stronger in multiparae than in primiparae and the risk is higher for heavy smokers.

Effect of cigarette smoke on placental antioxidant enzyme expression

Cigarette smoking is associated with systemic oxidative stress leading to an upregulation of antioxidant systems [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and heme oxygenase (HO)] in some tissues, but the response in the human placenta is unknown. The aim of this study was to determine the effect of cigarette smoke exposure on placental antioxidant expression in vivo, as well as the effect on antioxidant expression in the human trophoblast choriocarcinoma (HTR)-8SVNeo cell line. In the in vivo experiment, normal-term placentas were obtained following elective caesarean section. The chorionic villi (CV), anchoring villi (AV), and basal plate (BP) were dissected, and Western blot analysis was carried out for HO-1, HO-2, SOD, CAT, and GPx. In vitro experiment, a cigarette smoke extract (CSE) was prepared by bubbling the smoke form three cigarettes through 15 ml of RPMI. This 100% CSE was syringe filtered and diluted to 0.1, 0.5, 1, 2, 5, and 10% concentrations. HTR-8SVNeo cells were cultured with the CSE for 48 h. The cells were harvested, protein was extracted, and run on SDS-PAGE gels, and Western blot analysis was carried out for HO-1, HO-2, SOD, and CAT. Immunofluorescence for HTR-8SVNeo cells HO-1 was carried out following increasing concentrations of CSE. In the in vivo experiment, HO-1 and HO-2 expression was increased in the BP of placentas from smokers compared with nonsmokers. CAT, GPx, and SOD levels in all placental regions, as well as HO-1 and HO-2 expression in the AV and CV were unchanged. In the in vitro experiment, The 5%, 10%, and 20% dilutions were toxic to the cells. The 0.1% CSE solution did not significantly alter HO-1 expression. Treatment with the 0.5%, 1% and 2% CSE solutions resulted in a dose-dependent increase in HO-1 expression. None of the CSE treatments resulted in a significant alteration in HO-2, SOD, GPx, or CAT expression. HO-1 immunoflourescence confirmed the HO-1 expression studies. Cigarette smoke exposure increases HO-1 and HO-2 expression in the placental basal plate and increases HO-1 expression in the HTR-8SVNeo cell line. Increased HO-1 and HO-2 protein expression may increase the production of the antioxidants biliverdin and bilirubin, which are products of heme metabolism. This could function to reduce the oxidative load that is released into the maternal plasma from the preeclamptic placenta and may contribute to the observed decreased incidence of preeclampsia in smokers.