Spontaneous preterm birth and small for gestational age infants in women who stop smoking early in pregnancy: prospective cohort study

Association between maternal cigarette smoking cessation and risk of preterm birth in Western New York

BACKGROUND

Although many studies suggested the benefit of smoking cessation among pregnant women in reducing the risk of preterm birth (PTB), the timing of the effect of the cessation remains inconclusive.

OBJECTIVES

To examine the association of trimester-specific smoking cessation behaviours with PTB risk.

METHODS

We included 199,453 live births in Western New York between 2004 and 2018. Based on self-reported cigarette smoking during preconception and in each trimester, we created six mutually exclusive groups: non-smokers, quitters in each trimester, those who smoked throughout pregnancy, and inconsistent smokers. Risk ratios (RRs) and 95% confidence intervals (CIs) were estimated using Poisson regression to examine the association between smoking cessation and PTB. Effect modification by illegal drug use, maternal age, race and ethnicity and pre-pregnancy body mass index (BMI) was investigated multiplicatively by ratio of relative risk and additively by relative excess risk due to interaction (RERI).

RESULTS

Overall, 6.7% of women had a PTB; 14.1% smoked throughout pregnancy and 3.4%, 1.8% and 0.8% reported quitting smoking during the first, second and third trimesters, respectively. Compared to non-smokers, third-trimester cessation (RR 1.20, 95% CI 1.01, 1.43) and smoking throughout pregnancy (RR 1.27, 95% CI 1.21, 1.33) were associated with a higher PTB risk, while quitting smoking during the first or second trimester, or inconsistent smoking was not associated with PTB. A positive additive interaction was identified for maternal age and late smoking cessation or smoking throughout pregnancy on PTB risk (RERI 0.17, 95% CI 0.00, 0.36), and a negative interaction was observed for pre-pregnancy BMI ≥30 kg/m2 (ratio of relative risk 0.70, 95% CI 0.63, 0.78; RERI -0.42, 95% CI -0.56, -0.30).

CONCLUSION

Compared to non-smokers, smoking throughout pregnancy and third-trimester smoking cessation are associated with an increased risk of PTB, while quitting before the third trimester may not increase PTB risk.

Maternal smoking during pregnancy links to childhood blood pressure through birth weight and body mass index: NHANES 1999-2018

Maternal smoking during pregnancy (MSDP) is associated with lower birth weight, childhood obesity, and elevated blood pressure (BP) in offspring. We aimed to examine whether birth weight and body mass index (BMI) mediate the effect of MSDP on BP in children. The study included 14,713 children aged 8 to 15 years from the National Health and Nutrition Examination Surveys from 1999 to 2018. General third-variable models were used to examine the mediating effects of birth weight and BMI on the association of MSDP with BP. A total of 1928 (13.1%) children were exposed to MSDP. MSDP was associated with reduced birth weight (p < 0.001), increased BMI (p < 0.001), and elevated systolic BP (p = 0.005). MSDP was not associated with systolic BP after adjustment for birth weight and BMI z-score (p = 0.875), with 95.0% of the effect of MSDP on BP mediated by birth weight (39.1%) and BMI (55.9%). In conclusion, lower birth weight and increased obesity measures mediate the adverse effects of MSDP on BP in children. These findings provide novel mechanistic insight into the adverse effect of MSDP on BP in children and have implications for preventing hypertension in later life.

High-Sensitivity Cardiac Troponin I Enhances Preeclampsia Prediction Beyond Maternal Factors and the sFlt-1/PlGF Ratio

BACKGROUND

Preeclampsia shares numerous risk factors with cardiovascular diseases. Here, we aimed to assess the potential utility of high-sensitivity cardiac troponin I (hs-cTnI) values during pregnancy in predicting preeclampsia occurrence.

METHODS

This study measured hs-cTnI levels in 3721 blood samples of 2245 pregnant women from 4 international, prospective cohorts. Three analytical approaches were used: (1) a cross-sectional analysis of all women using a single blood sample, (2) a longitudinal analysis of hs-cTnI trajectories in women with multiple samples, and (3) analyses of prediction models incorporating hs-cTnI, maternal factors, and the sFlt-1 (soluble fms-like tyrosine kinase 1)/PlGF (placental growth factor) ratio.

RESULTS

Women with hs-cTnI levels in the upper quarter had higher odds ratios for preeclampsia occurrence compared with women with levels in the lower quarter. Associations were driven by preterm preeclampsia (odds ratio, 5.78 [95% CI, 2.73-12.26]) and remained significant when using hs-cTnI as a continuous variable adjusted for confounders. Between-trimester hs-cTnI trajectories were independent of subsequent preeclampsia occurrence. A prediction model incorporating a practical hs-cTnI level of detection cutoff (≥1.9 pg/mL) alongside maternal factors provided comparable performance with the sFlt-1/PlGF ratio. A comprehensive model including sFlt-1/PlGF, maternal factors, and hs-cTnI provided added value (cross-validated area under the receiver operator characteristic, 0.78 [95% CI, 0.73-0.82]) above the sFlt-1/PlGF ratio alone (cross-validated area under the receiver operator characteristic, 0.70 [95% CI, 0.65-0.76]; P=0.027). As assessed by likelihood ratio tests, the addition of hs-cTnI to each prediction model significantly improved the respective prediction model not incorporating hs-cTnI, particularly for preterm preeclampsia. Net reclassification improvement analyses indicated that incorporating hs-cTnI improved risk prediction predominantly by correctly reclassifying women with subsequent preeclampsia occurrence.

CONCLUSIONS

These exploratory findings uncover a potential role for hs-cTnI as a complementary biomarker in the prediction of preeclampsia. After validation in prospective studies, hs-cTnI, alongside maternal factors, may either be considered as a substitute for angiogenic biomarkers in health care systems where they are sparce or unavailable, or as an enhancement to established prediction models using angiogenic markers.

Fetal Growth Restriction: A Comprehensive Review of Major Guidelines

Importance

Fetal growth restriction (FGR) is a common pregnancy complication and a significant contributor of fetal and neonatal morbidity and mortality, mainly due to the lack of effective screening, prevention, and management policies.

Objective

The aim of this study was to review and compare the most recently published influential guidelines on the management of pregnancies complicated by FGR.

Evidence Acquisition

A descriptive review of guidelines from the American College of Obstetricians and Gynecologists (ACOG), the Society for Maternal-Fetal Medicine, the International Federation of Gynecology and Obstetrics, the International Society of Ultrasound in Obstetrics and Gynecology, the Royal College of Obstetricians and Gynecologists, the Society of Obstetricians and Gynecologists of Canada (SOGC), the Perinatal Society of Australia and New Zealand, the Royal College of Physicians of Ireland, the French College of Gynecologists and Obstetricians (FCGO), and the German Society of Gynecology and Obstetrics on FGR was carried out.

Results

Several discrepancies were identified regarding the definition of FGR and small-for-gestational-age fetuses, the diagnostic criteria, and the need of testing for congenital infections. On the contrary, there is an overall agreement among the reviewed guidelines regarding the importance of early universal risk stratification for FGR to accordingly modify the surveillance protocols. Low-risk pregnancies should unanimously be evaluated by serial symphysis fundal height measurement, whereas the high-risk ones warrant increased sonographic surveillance. Following FGR diagnosis, all medical societies agree that umbilical artery Doppler assessment is required to further guide management, whereas amniotic fluid volume evaluation is also recommended by the ACOG, the SOGC, the Perinatal Society of Australia and New Zealand, the FCGO, and the German Society of Gynecology and Obstetrics. In case of early, severe FGR or FGR accompanied by structural abnormalities, the ACOG, the Society for Maternal-Fetal Medicine, the International Federation of Gynecology and Obstetrics, the Royal College of Obstetricians and Gynecologists, the SOGC, and the FCGO support the performance of prenatal diagnostic testing. Consistent protocols also exist on the optimal timing and mode of delivery, the importance of continuous fetal heart rate monitoring during labor, and the need for histopathological examination of the placenta after delivery. On the other hand, guidelines concerning the frequency of fetal growth and Doppler velocimetry evaluation lack uniformity, although most of the reviewed medical societies recommend an average interval of 2 weeks, reduced to weekly or less when umbilical artery abnormalities are detected. Moreover, there is a discrepancy on the appropriate timing for corticosteroids and magnesium sulfate administration, as well as the administration of aspirin as a preventive measure. Cessation of smoking, alcohol consumption, and illicit drug use are proposed as preventive measures to reduce the incidence of FGR.

Conclusions

Fetal growth restriction is a clinical entity associated with numerous adverse antenatal and postnatal events, but currently, it has no definitive cure apart from delivery. Thus, the development of uniform international protocols for the early recognition, the adequate surveillance, and the optimal management of growth-restricted fetuses seem of paramount importance to safely guide clinical practice, thereby improving perinatal outcomes of such pregnancies.

Are Babies Born Preterm High-Risk Asthma Candidates?

Among preterm infants, the risk of developing asthma is a matter of debate. This review discusses the state of the art of poorly understood prematurity-associated asthma. Impaired pulmonary function is common in children born prematurely. Preterm infants are prone to developing viral respiratory tract infections, bronchiolitis in the first year of life, and recurrent viral wheezing in preschool age. All of these conditions may precede asthma development. We also discuss the role of both atopic sensitization and intestinal microbiome and, consequently, immune maturation. Diet and pollution have been considered to better understand how prematurity could be associated with asthma. Understanding the effect of factors involved in asthma onset may pave the way to improve the prediction of this asthma phenotype.

Prenatal nicotine exposure during pregnancy results in adverse neurodevelopmental alterations and neurobehavioral deficits

Maternal tobacco use and nicotine exposure during pregnancy have been associated with adverse birth outcomes in infants and can lead to preventable pregnancy complications. Exposure to nicotine and other compounds in tobacco and electronic cigarettes (e-cigarettes) has been shown to increases the risk of miscarriage, prematurity, stillbirth, low birth weight, perinatal morbidity, and sudden infant death syndrome (SIDS). Additionally, recent data provided by clinical and pre-clinical research demonstrates that nicotine exposure during pregnancy may heighten the risk for adverse neurodevelopmental disorders such as Attention-Deficit Hyperactivity (ADHD), anxiety, and depression along with altering the infants underlying brain circuitry, response to neurotransmitters, and brain volume. In the United States, one in 14 women (7.2%) reported to have smoked cigarettes during their pregnancy with the global prevalence of smoking during pregnancy estimated to be 1.7%. Approximately 1.1% of women in the United States also reported to have used e-cigarettes during the last 3 months of pregnancy. Due to the large percentage of women utilizing nicotine products during pregnancy in the United States and globally, this review seeks to centralize pre-clinical and clinical studies focused on the neurobehavioral and neurodevelopmental complications associated with prenatal nicotine exposure (PNE) such as alterations to the hypothalamic-pituitary-adrenal (HPA) axis and brain regions such as the prefrontal cortex (PFC), ventral tegmental area (VTA), nucleus accumbens (NA), hippocampus, and caudate as well as changes to nAChR and cholinergic receptor signaling, long-term drug seeking behavior following PNE, and other related developmental disorders. Current literature analyzing the association between PNE and the risk for offspring developing schizophrenia, attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), anxiety, and obesity will also be discussed.

Secular trends of low birth weight, preterm birth, and small for gestational age in Shanghai from 2004 to 2020: an age-period-cohort analysis

BACKGROUND

Although highly heterogeneous among countries, the incidence rates of low birth weight (LBW), preterm birth (PTB), and small for gestational age (SGA) have been increasing globally over the past two decades. To better understand the cause of these secular trends, this study aimed to investigate the effects of age, period, and birth cohort on LBW, PTB, and SGA rates in Shanghai.

METHODS

Data from 2,958,695 singleton live births at 24-41 gestational weeks between 2004 and 2020 were obtained for this study. Age-period-cohort models based on Poisson regression were used to evaluate the independent effects of maternal age, delivery period, and maternal birth cohort on the trends in LBW, PTB, and SGA.

RESULTS

The overall prevalence rates of LBW, PTB, and SGA were 2.9%, 4.7%, and 9.3%, respectively, and significant changes were observed (average annual change: + 10.7‰, + 9.1‰, -11.9‰) from 2004 to 2020. Cohort effect increased steadily, from 1960 (risk ratio [RR] = 0.71, 95% confidence interval [CI]: 0.65-0.78) to 1993 (RR = 0.97, 95% CI: 0.94-1.01) for LBW and from 1960 (RR = 0.69, 95% CI: 0.64-0.75) to 2004 (RR = 1.02, 95% CI: 0.94-1.12) for PTB. A strong cohort effect was found with the highest risk of SGA (RR = 1.82, 95% CI: 1.72-1.93) in 1960 and the lowest risk (RR = 0.57, 95% CI: 0.54-0.61) in 2004, compared with the reference cohort of 1985. There was a "U-shaped" maternal age effect on LBW and PTB and a weak period effect on the three birth outcomes.

CONCLUSIONS

Our findings suggested a significant independent effect of age, period, and birth cohort on the three birth outcomes. The increasing rates of LBW and PTB motivated us to focus on young and advanced pregnant women. Meanwhile, the prevalence of SGA decreased steadily, illustrating the need for further research on the mechanisms underlying these trends.

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.

A mixed methods evaluation of Quit for new life, a smoking cessation initiative for women having an Aboriginal baby

BACKGROUND

Quit for new life (QFNL) is a smoking cessation initiative developed to support mothers of Aboriginal babies to quit smoking during pregnancy. The state-wide initiative provides support for pregnant women and their households including free nicotine replacement therapy (NRT) and follow up cessation advice. Services are also supported to implement systems-level changes and integrate QFNL into routine care. This study aimed to evaluate: (1) models of implementation of QFNL; (2) the uptake of QFNL; (3) the impact of QFNL on smoking behaviours; and (4) stakeholder perceptions of the initiative.

METHODS

A mixed methods study was conducted comprising semi-structured interviews and analysis of routinely collected data. Interviews were conducted with 6 clients and 35 stakeholders involved in program implementation. Data were analysed using inductive content analysis. Aboriginal Maternal and Infant Health Service Data Collection (AMDC) records for the period July 2012-June 2015 were investigated to examine how many eligible women attended a service implementing QFNL and how many women took up a QFNL support. Smoking cessation rates were compared in women attending a service offering QFNL with women attending the same service prior to the implementation of QFNL to determine program impact.

RESULTS

QFNL was implemented in 70 services located in 13 LHDs across New South Wales. Over 430 staff attended QFNL training, including 101 staff in Aboriginal-identified roles. In the period July 2012-June 2015 27% (n = 1549) of eligible women attended a service implementing QFNL and 21% (n = 320) of these were recorded as taking up a QFNL support. While stakeholders shared stories of success, no statistically significant impact of QFNL on smoking cessation rates was identified (N = 3502; Odds ratio (OR) = 1.28; 95% Confidence Interval (CI) = 0.96-1.70; p-value = 0.0905). QFNL was acceptable to both clients and stakeholders, increased awareness about smoking cessation, and gave staff resources to support clients.

CONCLUSION

QFNL was perceived as acceptable by stakeholders and clients and provided care providers with knowledge and tangible support to offer women who presented at antenatal care as smokers, however, no statistically significant impact on rates of smoking cessation were found using the measures available.

Evaluating association of smoking status during pregnancy with adverse birth outcomes using urinary cotinine concentration: The Japan environment and Children's study (JECS)

Urinary cotinine concentration (UCC) reflects smoking status. However, in pregnant women, its association with adverse birth outcomes related to fetal growth is not widely known. Thus, we aimed to explore this relationship by focusing on dose-response relationships. We investigated 86,638 pregnant women enrolled between 2011 and 2014 in a prospective cohort study in Japan and observed three birth outcomes (preterm birth, low birth weight, and small-for-gestational age). We measured UCC in the second or third trimester, and categorized the participants using cut-off values (negative cotinine concentration, passive cotinine concentration, and active cotinine concentration corresponding to non-smokers, passive smokers, and active smokers, respectively). Logistic regression analyses were conducted to evaluate the risks, and dose-response relationships were visualized using restricted cubic spline curves. Analyses based on self-reported smoking status were also performed. We found that in low active and highly active cotinine concentrations, the adjusted odds ratios (aORs) of birth outcomes were significantly increased (preterm birth, 1.24 [95% CI 1.06-1.46], 1.39 [95% CI 1.19-1.62]; low birth weight, 1.40 [95% CI 1.24-1.58], 2.27 [95% CI 2.05-2.53]; small-for-gestational age, 1.35 [95% CI 1.19-1.52], 2.39 [95% CI 2.16-2.65]). Restricted cubic spline curves demonstrated risk elevations in the active cotinine concentration range. Our research revealed dose-response relationships between UCC during pregnancy and the risks of preterm birth, low birth weight, and small-for-gestational age. Measurement of UCC to ascertain smoking status during pregnancy may be a useful approach for predicting the risks of these birth outcomes.

The Outcome of Pregnancy Among Tobacco Users in Tertiary Care Hospital of Chhattisgarh Province of India

BACKGROUND

Tobacco use is responsible for numerous adverse pregnancy outcomes for females and their infants. The aim of this study was to explore the adverse outcome of tobacco use among pregnant females.

METHOD

 A cross-sectional study was conducted on 1250 females in the third trimester of pregnancy from April to June 2022, which were exposed to tobacco use in the form of gudaku, tobacco chewing, gutka, or smoking. Complications and outcomes during and after pregnancy were recorded based on self-administered questionnaires. Statistical analysis was performed using the Statistical Package for Social Sciences (SPSS) (IBM SPSS Statistics, Armonk, NY) software version 20.0 for categorical data, frequencies (n) and percentages (%) were calculated, and the chi-square test was used for determining intergroup differences.

RESULTS

 Out of 1250 females, tobacco exposure was present among 429 (34.3%), and 821 (65.7%) had no tobacco exposure. Of 429, 36.10% of females complained about complications such as abortion (1.60%), antepartum hemorrhage (0.90%), congenital anomaly (0.20%), infertility (1.20%), intrauterine fetal death (IUFD) (0.50%), intrauterine growth restriction (IUGR) (0.90%), oligohydramnios (OLIGO) (3.30%), preterm labor (18.40%), premature rupture of membrane (6.30%), and anemia (2.80%), which were slightly higher than the females with no tobacco exposure. In tobacco users, obstructive complications were found to be significant with a p value of 0.0036.

CONCLUSION

Our study concluded that tobacco use could have an adverse effect on their fetus and infants, as well as the pregnant females themselves. Policymakers need to ensure effective strategies that pregnant females, their partners, and close relatives need to have enough knowledge to avoid potential risks.

Does Maternal Obesity Affect Preterm Birth? Documentary Cohort Study of Preterm in Firstborns—Silesia (Poland)

In addition to low birth weight and intrauterine growth restriction, prematurity is a major problem in modern neonatology. The etiology of premature delivery is multifactorial, but maternal obesity has been indicated as an important risk factor for preterm birth. This study aimed to assess the relationship between early pregnancy body mass index (BMI) and the risk of preterm delivery according to gestational age. In the cohort of 2794 firstborns, preterm deliveries accounted for 9.1%. Of all deliveries, 16, 48, and 189 were classified as extremely preterm, very preterm, and moderately preterm deliveries, respectively. The risk of extremely, very, and moderately preterm deliveries increased with the increasing BMI, with the highest overweight and obesity-related risk for extremely and very preterm delivery. The rate of extremely and very preterm delivery among normal-weight women (BMI 18.5 ≤ 25) was 1.8%, while that among overweight and obese women (BMI ≥ 25) was 2.36%. The rate of all preterm deliveries (22 ≤ 37 weeks) was 8% for normal-weight women and 10.3% for overweight and obese women. Compared with normal-weight women, the adjusted odds ratio (95% CI) for preterm delivery in overweight and obese women was 1.33 (0.98–1.79). In Poland, being overweight and obese during pregnancy was associated with an increased risk of preterm delivery, especially extremely and very preterm delivery. This relationship should be assessed in other populations.

Periconceptual and prenatal alcohol consumption and neurodevelopment at age two and five years

OBJECTIVE

Examine the association between alcohol consumption before and during pregnancy and neurodevelopmental outcomes in the offspring at two and five years.

STUDY DESIGN

Retrospective analysis of a prospective longitudinal cohort; SCOPE-BASELINE. Data on pre-conception and prenatal alcohol consumption were obtained at 15 weeks' gestation and categorised as abstinent, occasional-low (1-7units/week) and moderate-heavy (≥8units/week). Binge drinking was defined as ≥6 units/session. Outcome measures (Child Behaviour Checklist and Kaufman Brief Intelligence Test) were obtained at two and five years. Linear regression examined an alcohol consumption and Child Behaviour Checklist and Kaufman Brief Intelligence Test relationship, adjusting for several potential confounders.

RESULTS

Data on alcohol consumption was available for 1,507 women. Adjusted linear regression suggested few associations: pre-pregnancy occasional-low alcohol consumption was associated with lower log externalizing Child Behaviour Checklist scores (-0.264, 95% CI: -0.009, -0.520), while pre-pregnancy moderate-high levels of alcohol consumption was associated with lower Kaufman Brief Intelligence Test verbal standard scores (-0.034, 95% CI: -0.001, -0.068) and composite IQ scores (-0.028, 95% CI: -0.056, -0.0004) at five-years. In the first trimester, moderate-high levels of alcohol consumption was associated with lower internalizing Child Behaviour Checklist scores at two-years (-0.252, 95% CI: -0.074, -0.430). No significant associations were observed between number of binge episodes pre-pregnancy or binge drinking in the first trimester and Child Behaviour Checklist or Kaufman Brief Intelligence Test.

CONCLUSIONS

We did not find strong evidence of associations between pre-pregnancy and early pregnancy maternal alcohol consumption and adverse neurodevelopmental outcomes at age two and five years overall. Further research examining alcohol consumption (including binge drinking) beyond 15 weeks' gestation and subsequent neurodevelopmental outcomes is needed to examine the potential effect of alcohol consumption in later pregnancy.

Risk scores for predicting small for gestational age infants in Japan: The TMM birthree cohort study

This study aimed to construct a prediction model for small-for-gestational-age (SGA) infants in Japan by creating a risk score during pregnancy. A total of 17,073 subjects were included in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study, a prospective cohort study. A multiple logistic regression model was used to construct risk scores during early and mid-gestational periods (11–17 and 18–21 weeks of gestation, respectively). The risk score during early gestation comprised the maternal age, height, body mass index (BMI) during early gestation, parity, assisted reproductive technology (ART) with frozen-thawed embryo transfer (FET), smoking status, blood pressure (BP) during early gestation, and maternal birth weight. The risk score during mid-gestation also consisted of the maternal age, height, BMI during mid-gestation, weight gain, parity, ART with FET, smoking status, BP level during mid-gestation, maternal birth weight, and estimated fetal weight during mid-gestation. The C-statistics of the risk scores during early- and mid-gestation were 0.658 (95% confidence interval [CI]: 0.642–0.675) and 0.725 (95% CI: 0.710–0.740), respectively. In conclusion, the predictive ability of the risk scores during mid-gestation for SGA infants was acceptable and better than that of the risk score during early gestation.

Isolation, marginalisation and disempowerment - understanding how interactions with health providers can influence smoking cessation in pregnancy

Background

Maternal smoking during pregnancy can lead to serious adverse health outcomes for both women and their infants. While smoking in pregnancy has declined over time, it remains consistently higher in women with lower socioeconomic circumstances. Furthermore, fewer women in this group will successfully quit during pregnancy.

Aim

This study explores the barriers to smoking cessation experienced by socially disadvantaged pregnant women and investigates how interactions with health providers can influence their smoking cessation journey.

Methods

Women (either pregnant or birthed in the previous 10 years, who smoked or quit smoking in pregnancy) were recruited from a metropolitan public hospital antenatal clinic in South Australia and community organisations in surrounding suburbs. Seventeen women participated in qualitative semi-structured small focus groups or interviews. The focus groups and interviews were recorded, transcribed and thematically analysed.

Findings

Four interconnected themes were identified: 1) smoking embedded in women’s challenging lives and pregnancies, 2) cyclic isolation and marginalisation, 3) feeling disempowered, and 4) autonomy and self-determination. Themes 3 and 4 are characterised as being two sides of a single coin in that they coexist simultaneously and are inseparable. A key finding is a strong unanimous desire for smoking cessation in pregnancy but women felt they did not have the necessary support from health providers or confidence and self-efficacy to be successful.

Conclusion

Women would like improvements to antenatal care that increase health practitioners’ understanding of the social and contextual healthcare barriers faced by women who smoke in pregnancy. They seek improved interventions from health providers to make informed choices about smoking cessation and would like women-centred care. Women feel that with greater support, more options for cessation strategies and consistency and encouragement from health providers they could be more successful at antenatal smoking cessation. If such changes were made, then South Australian practice could align more with best practice international guidelines for addressing smoking cessation in pregnancy, and potentially improve outcomes for women and their children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04720-0.

Cardio-Obstetrics: the Next Frontier in Cardiovascular Disease Prevention

Purpose of Review

Internationally, cardiovascular disease (CVD) is the leading cause of death in women. With risk factors for CVD continuing to rise, early identification and management of chronic diseases such as hypertension, diabetes, and obstructive sleep apnea is necessary for prevention. Pregnancy is a natural stress test for women with risk factors who may be predisposed to CVD and offers a unique opportunity to not only recognize disease but also implement effective and long-lasting strategies for prevention.

Recent Findings

Prevention begins before pregnancy, as preconception screening, counseling, and optimization of chronic diseases can improve maternal and fetal outcomes. Throughout pregnancy, women should maintain close follow-up, continued reevaluation of risk factors, with counseling when necessary. Continued healthcare engagement during the “fourth trimester,” 3 months following delivery, allows clinicians to continue monitoring the evolution of chronic diseases, encourage ongoing lifestyle counseling, and connect women with primary care and appropriate specialists if needed. Unfortunately, this postpartum period represents a major care gap, as a significant proportion of most women do not attend their scheduled visits. Social determinants of health including decreased access to care and economic instability lead to increased risk factors throughout pregnancy but particularly play a role in poor compliance with postpartum follow-up. The use of telemedicine clinics and remote monitoring may prove to be effective interventions, bridging the gap between physicians and patients and improving follow-up for at-risk women.

Summary

While many clinicians are beginning to understand the impact of CVD on women, screening and prevention strategies are not often implemented until much later in life. Pregnancy creates an opportunity to begin engaging women in cardiovascular protective strategies before the development of the disease.

'I don't need you to criticise me, I need you to support me'. A qualitative study of women's experiences of and attitudes to smoking cessation during pregnancy

BACKGROUND

Smoking is associated with health inequalities and is the most important modifiable risk factor for poor outcome in pregnancy.

AIM

To explore women's experiences of smoking during pregnancy, examine their attitudes and barriers to smoking cessation, and to discover what support they feel might enable them to have a smoke-free pregnancy in future.

METHODS

A qualitative study was conducted with nineteen women in the United Kingdom who had smoked at some stage in pregnancy during the last five years. Data were collected through in-depth telephone interviews between June and August 2021. The interviews were audio-recorded, transcribed verbatim, and thematically analysed.

FINDINGS

Four key themes were identified: the complex relationship with smoking, being ready to quit, the need for support and understanding, and ideas to support a smoke free pregnancy. The findings revealed that there were two distinct avenues for enabling the support process: encouraging a readiness to quit through identifying individual context, personalised support, and educational risk perception, and, supporting the process of quitting, and offering a range of options, underpinned by a personalised, non-judgemental approach.

CONCLUSION

Smoking in pregnancy is a complex issue resulting from a combination of social, emotional, and physical factors. The findings from this study suggest that a combination of approaches should be made available to enable pregnant women who smoke to select the best options for their individual needs. Irrespective of the practical support offered, there is a need for informed, sensitive, individualised support system that women can identify with.

Tobacco and Cannabis Use During Pregnancy

OBJECTIVES

Nicotine (NIC) use during pregnancy can influence markers used in biochemical maternal serum screening. This study was designed to determine prevalence of disclosed tobacco smokers in our patient population and to compare disclosed tobacco smoking status with the presence of serum nicotine and a common tetrahydrocannabinol (THC) metabolite.

METHODS

A deidentified dataset of disclosed smoking status for quadruple (Quad) screens was obtained. Residual serum submitted for Quad screens was obtained from frozen storage and analyzed for NIC and THC metabolites.

RESULTS

Of specimens that had corresponding responses to the smoking history question on the patient history form, 7.2% (n = 1,783 of 24,611) specified that the patient was a tobacco smoker. Of the 271 specimens biochemically analyzed for NIC and THC metabolites, disclosed tobacco smokers had the highest prevalence of detectable NIC and THC metabolites. THC product use was most prevalent in patients categorized as probable tobacco smokers based on cotinine concentrations, as well as in younger patients.

CONCLUSIONS

Prevalence and concentration of NIC and THC metabolites vary based on disclosed tobacco smoker status. Biochemical testing may increase sensitivity for the identification of NIC and THC status over self-reporting.

An eight-plex immunoassay for Group A streptococcus serology and vaccine development

Group A Streptococcus (GAS) is a major human pathogen responsible for superficial infections through to life-threatening invasive disease and the autoimmune sequelae acute rheumatic fever (ARF). Despite a significant global economic and health burden, there is no licensed vaccine available to prevent GAS disease. Several pre-clinical vaccines that target conserved GAS antigens are in development. Assays that measure antigen-specific antibodies are essential for vaccine research. The aim of this study was to develop a multiplex beadbased immunoassay that can detect and quantify antibody responses to multiple GAS antigen targets in small volume blood samples. This builds on our existing triplex assay comprised of antigens used in clinical serology for the diagnosis of ARF (SLO, DNase B and SpnA). Five additional conserved putative GAS vaccine antigens (Spy0843, SCPA, SpyCEP, SpyAD and the Group A carbohydrate), were coupled to spectrally unique beads to form an 8-plex antigen panel. After optimisation of the assay protocol, standard curves were generated, and assessments of assay specificity, precision and reproducibility were conducted. A broad range of antibody (IgG) titres were able to be quickly and accurately quantified from a single serum dilution. Assay utility was assessed using a panel of 62 clinical samples including serum from adults with GAS bacteraemia and children with ARF. Circulating IgG to all eight antigens was elevated in patients with GAS disease (n = 23) compared to age-matched controls (n = 39) (P < 0.05). The feasibility of using dried blood samples to quantify antigen-specific IgG was also demonstrated. In summary, a robust and reproducible 8-plex assay has been developed that simultaneously quantifies IgG antibodies to GAS vaccine and diagnostic antigens.

Community Pharmacist-Led Interventions to Improve Preconception and Pregnancy Health: A Systematic Review

Background: Community pharmacist-led interventions are effective in improving health outcomes; however, their impact in improving preconception and pregnancy health is not clear. This study evaluated the effectiveness of community pharmacist-led interventions which aimed to improve health outcomes of preconception and pregnant women. Methods: A systematic review of the literature, consistent with PRISMA guidelines, was performed. Five electronic databases were searched up to February 2021. Results: Four studies, three in pregnant women and one in preconception women, were identified. The studies focused on improving micronutrient status and smoking cessation. The studies increased knowledge about, and use of, iron supplements, and improved iron status and smoking cessation rates in pregnant women, while improving knowledge regarding, and increasing the use of, preconception folic acid. The studies were ranked as weak to moderate quality. Conclusion: This review provides preliminary evidence for the potential benefit of community pharmacist-led interventions to improve the health of women before and during pregnancy.

Does it matter when I quit? Could I just cut down some? Links between trimester-specific smoking amount, preterm birth, and low birth weight

BACKGROUND

Substantial evidence demonstrates the harms of pregnancy smoking. Due to the need for very large data sets, less data exist to inform decisions about when quitting should occur, or whether a certain amount of reduction is beneficial.

OBJECTIVES

Our goal was to examine the effect of timing and amount of pregnancy smoking on low birth weight (LBW) and preterm birth (PTB).

METHODS

Data for 3 years of registered births in Tennessee were available and included standard birth certificate information.

RESULTS

Of 241,616 women, 15.7% smoked at conception, and those who quit as early as the first trimester had significantly increased adjusted odds of LBW (27%) and PTB (14%) compared to nonsmokers, with this effect largely driven by smoking 10+ cigarettes per day. Smoking into the second trimester but quitting prior to the third also predicted increases in LBW and PTB compared to both not smoking at all and smoking only in the first trimester. Smoking to delivery predicted a 2.8-fold increased likelihood of LBW, and a 2.1-fold increased rate of PTB. Any level of smoking after the first trimester substantially increased the odds of poor outcomes compared to both nonsmoking and smoking only in the first trimester.

CONCLUSIONS

Findings suggest that to avoid LBW or PTB, pregnant smokers should be advised that quitting completely by the end of the first trimester is important, and that continuing to smoke even <5 cigarettes per day after that point substantially increases the potential for of adverse outcomes.

Risk of adverse perinatal outcomes in infants born to mothers with mental health conditions

INTRODUCTION

Maternal mental health conditions have been shown to affect perinatal outcomes negatively. However, knowledge on the impact of different types and severities of maternal mental health conditions is needed. The objective of this study was to determine the association between maternal mental health status and perinatal health outcomes in the infant.

MATERIAL AND METHODS

This register-based cohort study included all live-born infants in Denmark born between 2000 and 2016. Exposed infants were grouped based on whether the mothers received mental health care in primary care settings only (minor conditions) or required specialized psychiatric intervention (moderate-severe conditions) within 12 months before childbirth. Modified Poisson regression analyses were applied to produce adjusted risk ratios (aRRs) for each perinatal outcome of interest. The primary outcomes were neonatal mortality, 5-minute Apgar scores <7 and <4 and newborn hospital admission during the neonatal period. Secondary outcomes included several neonatal morbidities such as respiratory distress syndrome and abstinence syndrome.

RESULTS

A total of 952 071 infants were included in the analysis; 4.0% had mothers with minor mental health conditions and 2.9% had mothers with moderate-severe conditions. The risk of neonatal death in exposed infants was aRR 1.08 (95% CI 0.93-1.27) for minor mental health conditions and aRR 0.93 (95% CI 0.78-1.11) for moderate-severe conditions. Both exposure groups had increased risks of 5-minute Apgar scores <7 (minor: aRR 1.28, 95% CI 1.16-1.41; moderate-severe: aRR 1.49, 95% CI 1.34-1.66); 5-minute Apgar scores <4 (minor: aRR 1.10, 95% CI 0.93-1.30; moderate-severe: aRR 1.18, 95% CI 0.98-1.43), and hospital admission during the neonatal period (minor: aRR 1.20, 95% CI 1.17-1.23; moderate-severe: aRR 1.22, 95% CI 1.19-1.26) along with several neonatal morbidities. An explicit high risk was seen for abstinence syndrome (minor: aRR 10.30, 95% CI 8.40-12.63; moderate-severe: aRR 12.13, 95% CI 10.17-15.67).

CONCLUSIONS

Infants of mothers with moderate-severe and minor mental health conditions were at increased risks of multiple adverse perinatal outcomes. Effective supportive interventions to improve outcomes in both groups are needed.

Behavioral Smoking Cessation Counseling During Pregnancy: A Cost-Effectiveness Analysis

OBJECTIVE

To examine the cost effectiveness of using behavioral smoking cessation counseling during pregnancy.

METHODS

We designed a decision-analytic model using TreeAge Pro 2020 software to compare the cost effectiveness and outcomes among women who received behavioral smoking cessation counseling compared with women who received usual care during pregnancy. We used a theoretical cohort of 285,000 women, the approximate number of pregnant women who smoke each year in the United States. Outcomes included maternal abstinence from smoking, fetal growth restriction, stillbirth, preterm delivery, neonatal death, and cerebral palsy, in addition to cost and quality-adjusted life-years (QALYs) for both the woman and the neonate. All model inputs were derived from the literature, and a willingness-to-pay threshold was set at $100,000 per QALY. Sensitivity analyses were performed to determine the robustness of baseline assumptions.

RESULTS

In our theoretical cohort, behavioral smoking cessation counseling compared with usual care was associated with 9,019 additional women stopping smoking during pregnancy (34,604 vs 25,585). Smoking cessation counseling also resulted in 911 fewer cases of fetal growth restriction, 20 fewer stillbirths, 250 fewer preterm deliveries, 11 fewer neonatal deaths, and one less case of cerebral palsy. Using behavioral smoking cessation counseling interventions during pregnancy led to better outcomes despite higher costs, with an incremental cost-effectiveness ratio of $71,658 per QALY, which was below our willingness-to-pay threshold of $100,000 per QALY, making the intervention cost effective. Sensitivity analyses demonstrated that the counseling intervention was cost effective at probabilities of smoking cessation greater than 11.6% (baseline input: 12.1%) or the cost of the behavioral intervention was less than $475.21 (baseline input: $368.78).

CONCLUSION

Behavioral smoking cessation counseling during pregnancy was associated with fewer adverse neonatal outcomes and was cost effective. Increasing utilization of such interventions and increasing insurance coverage of this care are important initiatives to improve outcomes in this at-risk population.

Mapping Autoantibodies in Children With Acute Rheumatic Fever

Background

Acute rheumatic fever (ARF) is a serious sequela of Group A Streptococcus (GAS) infection associated with significant global mortality. Pathogenesis remains poorly understood, with the current prevailing hypothesis based on molecular mimicry and the notion that antibodies generated in response to GAS infection cross-react with cardiac proteins such as myosin. Contemporary investigations of the broader autoantibody response in ARF are needed to both inform pathogenesis models and identify new biomarkers for the disease.

Methods

This study has utilised a multi-platform approach to profile circulating autoantibodies in ARF. Sera from patients with ARF, matched healthy controls and patients with uncomplicated GAS pharyngitis were initially analysed for autoreactivity using high content protein arrays (Protoarray, 9000 autoantigens), and further explored using a second protein array platform (HuProt Array, 16,000 autoantigens) and 2-D gel electrophoresis of heart tissue combined with mass spectrometry. Selected autoantigens were orthogonally validated using conventional immunoassays with sera from an ARF case-control study (n=79 cases and n=89 matched healthy controls) and a related study of GAS pharyngitis (n=39) conducted in New Zealand.

Results

Global analysis of the protein array data showed an increase in total autoantigen reactivity in ARF patients compared with controls, as well as marked heterogeneity in the autoantibody profiles between ARF patients. Autoantigens previously implicated in ARF pathogenesis, such as myosin and collagens were detected, as were novel candidates. Disease pathway analysis revealed several autoantigens within pathways linked to arthritic and myocardial disease. Orthogonal validation of three novel autoantigens (PTPN2, DMD and ANXA6) showed significant elevation of serum antibodies in ARF (p < 0.05), and further highlighted heterogeneity with patients reactive to different combinations of the three antigens.

Conclusions

The broad yet heterogenous elevation of autoantibodies observed suggests epitope spreading, and an expansion of the autoantibody repertoire, likely plays a key role in ARF pathogenesis and disease progression. Multiple autoantigens may be needed as diagnostic biomarkers to capture this heterogeneity.

Placental weight mediates association between prenatal exposure to cooking oil fumes and preterm birth

Background: There are some reports on association between maternal prenatal cooking oil fume (COF) exposure and preterm birth (PTB), but its mechanism remains poorly understood. Therefore, this study aims to assess whether placental weight mediates their associations.Method: We enrolled 619 pregnant women delivering PTB newborns as cases and 1701 delivering full-term appropriate for gestational age newborns as controls. They were inquired with a self-reported questionnaire about prenatal COF exposure, socio-demographics and obstetric characteristics at Women and Children's Hospitals of Shenzhen and Foshan. After controlling for the potential confounders, a series of logistic and linear regressions were conducted to assess associations among COF exposure, placental weight and PTB, and the mediation of placental weight in the association between COF exposure and PTB.Results: Maternal prenatal COF exposure was significantly associated with PTB and the frequency of prenatal COF exposure was negatively associated with placental weight. Compared with mother who never cooked, those cooking occasionally, sometimes or often increased the risk of PTB, and similarly, those cooking between half to an hour was also showed a higher risk of PTB. Typical Chinese cooking methods including stir-frying, pan-frying and deep-frying were also associated with PTB. Different oil types mainly used, including peanut oil, corn oil and animal oil were associated with PTB as well. Mediation analysis illustrated that placental weight partially mediated 13.60% (95% CI = 10.62-33.20%) of the effects on the association between the frequency of maternal prenatal COF exposure and PTB.Conclusion: Maternal cooking during pregnancy and the frequency of prenatal COF exposure might increase the risk of PTB, in which placenta might play mediation role.

FIGO (international Federation of Gynecology and obstetrics) initiative on fetal growth: best practice advice for screening, diagnosis, and management of fetal growth restriction

Fetal growth restriction (FGR) is defined as the failure of the fetus to meet its growth potential due to a pathological factor, most commonly placental dysfunction. Worldwide, FGR is a leading cause of stillbirth, neonatal mortality, and short- and long-term morbidity. Ongoing advances in clinical care, especially in definitions, diagnosis, and management of FGR, require efforts to effectively translate these changes to the wide range of obstetric care providers. This article highlights agreements based on current research in the diagnosis and management of FGR, and the areas that need more research to provide further clarification of recommendations. The purpose of this article is to provide a comprehensive summary of available evidence along with practical recommendations concerning the care of pregnancies at risk of or complicated by FGR, with the overall goal to decrease the risk of stillbirth and neonatal mortality and morbidity associated with this condition. To achieve these goals, FIGO (the International Federation of Gynecology and Obstetrics) brought together international experts to review and summarize current knowledge of FGR. This summary is directed at multiple stakeholders, including healthcare providers, healthcare delivery organizations and providers, FIGO member societies, and professional organizations. Recognizing the variation in the resources and expertise available for the management of FGR in different countries or regions, this article attempts to take into consideration the unique aspects of antenatal care in low-resource settings (labelled “LRS” in the recommendations). This was achieved by collaboration with authors and FIGO member societies from low-resource settings such as India, Sub-Saharan Africa, the Middle East, and Latin America.

Association between environmental tobacco smoke before and during pregnancy and the risk of adverse birth outcomes: a birth cohort study in Wuhan, China

Associations between environmental tobacco smoke (ETS) and the risk of adverse birth outcomes may be confounded. We aimed to clarify the associations of ETS before and during pregnancy with the risk of adverse birth outcomes and determine whether the associations were modified by key potential confounders. A total of 7147 non-smoking mothers from the Tongji Maternal and Child Health Cohort (TMCHC) in Wuhan, China, were included in the final analyses. ETS status was self-reported by pregnant women at their first antenatal care visit before 16 gestational weeks. Information on birth outcomes was extracted from delivery records. Poisson regression was used to identify the association between ETS before and during pregnancy and the risk of adverse birth outcomes. Exposures to ETS before and during pregnancy were reported by 645 (9.0%) and 464 (6.5%) mothers, respectively. Compared with no ETS, continued ETS during pregnancy was associated with an increased risk of preterm birth (PTB) (RR: 1.55, 95% CI: 1.07, 2.25) after adjustment for potential confounders. The association remained consistent in medically indicated PTB and late PTB. The risk of PTB associated with continued ETS during pregnancy was significantly increased in mothers more educated (P for interaction < 0.05). However, the increased risk of low birth weight (LBW) or small for gestational age (SGA) births by ETS during pregnancy was not observed. Exposure to ETS during pregnancy was associated with a higher risk of PTB, but not LBW or SGA births in a Chinese birth cohort.

Cardiac Risk Score to Predict Small-for-Gestational-Age Infants in Pregnant Women with Heart Disease

BACKGROUND

One of the most common fetal complications in pregnant women with cardiovascular disease is small for gestational age (SGA) which is associated with a higher risk of perinatal morbidity/mortality and poor long-term health outcomes. The objective of this study was to identify cardiac determinants/derive a risk score of clinically relevant SGA < 5^th percentile (SGA-5^th).

METHODS

A prospective cohort of 1812 pregnancies in women with heart disease was studied. SGA-5^th was the outcome of interest, defined as birth weight less than 5^th percentile for gestational age and sex. Multivariable logistic regression analysis identified predictors for SGA-5^th. Based on the regression coefficients a weighted risk score was created.

RESULTS

SGA-5^th complicated 10% of pregnancies, eleven predictors of SGA-5^th were identified and each was assigned a weighted score: maternal cyanosis (8), Fontan palliation (7), smoking (3), moderate or severe valvular regurgitation (3), beta-blocker use throughout pregnancy (4) or only in the 2^nd and 3^rd trimester (2), high baseline beta-blocker dose (4), BMI < 18.5 (3) or 18.5-24.9 (1), Asian/other ethnicity (2) and significant outflow tract obstruction (1). In the absence of identified risk factors, the risk of SGA-5^th was approximately 4%. Pregnancies with risk scores/SGA-5^th rate were as follows: 0/4%, 1/5%, 2/7%, 3/9%, 4/12%, 5/14%, 6/18%, 7/23%, 8/28% and ≥ 9/34%.

CONCLUSIONS

There are a number of cardiac predictors that are associated with increased risk of SGA-5^th. This is a prognostically important outcome and consideration should be given to routinely predicting and modifying the risk whenever possible.

A preconception intervention targeted at women with modifiable risk factors before pregnancy to improve outcomes; protocol for the Get Ready! feasibility trial

Background

The health of a woman before conception not only influences the outcome of her pregnancy but also the lifelong health of mother and child. Many women in the UK are inadequately prepared for pregnancy, with reports of a high prevalence of smoking, low folic acid supplement use, and suboptimal diet and physical activity. Get Ready! will link an online digital tool to identify women planning pregnancy most at risk of complications with a personalised intervention to improve health behaviours and biomarkers of metabolic health.

Methods

Women planning pregnancy will be identified from a free and widely used online preconception tool. A short online screening questionnaire will then be used to recruit women considered to be at high metabolic risk. Eligibility criteria include resident in the UK, age > 18–< 50 years, BMI ≥ 23 kg/m² (South Asian) or ≥ 25 kg/m² (all other ethnicities), and plus one or more of the following: 1st degree relative with type 2 diabetes, previous gestational diabetes (GDM), previous baby > 4 kg, or high risk ethnicity for GDM. Eligible women who consent to participate will be enrolled in a commercially available preconception intervention (Prepare Plans, LiveSmart UK Ltd). Following an online health assessment and home blood test, women will be provided with individualised lifestyle advice and coaching by dietitians. Process evaluation will provide an assessment of implementation of the intervention. Change in health behaviours and biomarkers of metabolic health will also be examined.

Discussion

Suboptimal health behaviours amongst women planning pregnancy are widely prevalent in the UK. Personalised health checks and coaching are especially important for women at risk of pregnancy complications. Get Ready! introduces a novel approach to identifying high risk women planning pregnancy and provision of a targeted intervention.

Registration

Trial sponsor: King’s College London.

Parity and the risks of adverse birth outcomes: a retrospective study among Chinese

Background

Nulliparity is considered to be a risk factor of preterm birth (PTB), low birth weight (LBW) and small for gestational age (SGA). With the new two-child policy launched in 2016, more Chinese women have delivered their 2nd baby. Yet few studies have assessed the impact of parity on adverse birth outcomes in China. This study aimed to examine the association between parity and risks of PTB, LBW and SGA in a Chinese population. The combined effects of maternal age and parity on adverse birth outcomes were also assessed.

Methods

This retrospective study included all non-malformed live births born during January 1, 2014 and December 31, 2018 in Chengdu, China. A total of 746,410 eligible live singletons with complete information were included in the analysis. Parity was classified into nulliparity (i.e. has never delivered a newborn before) and multiparity (i.e. has delivered at least one newborn before). Log-binomial regression analyses were applied to evaluate the association between parity and PTB, LBW and SGA. We further divided maternal age into different groups (< 25 years, 25–29 years, 30–34 years and ≥ 35 years) to assess the combined effects of maternal age and parity on adverse birth outcomes.

Results

Multiparity was associated with reduced risks of PTB (aRR = 0.91, 95% CI: 0.89–0.93), LBW (aRR = 0.74, 95% CI: 0.72–0.77) and SGA (aRR = 0.67, 95% CI: 0.66–0.69) compared with nulliparity. In each age group, we observed that multiparity was associated with lower risks of adverse birth outcomes. Compared to nulliparous women aged between 25 and 29 years, women aged ≥35 years had greater risks of PTB and LBW, regardless of their parity status. In contrast, multiparous women aged ≥35 years (aRR = 0.73, 95% CI: 0.70–0.77) and those aged < 25 years (aRR = 0.88, 95% CI: 0.84–0.93) were at lower risk of SGA compared with nulliparous women aged between 25 and 29 years.

Conclusion

Multiparity was associated with lower risks of all adverse birth outcomes. Special attention should be paid to nulliparous mothers and those with advanced age during antenatal care, in order to reduce the risks of adverse birth outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03718-4.

Prognostic factors associated with small for gestational age babies in a tertiary care hospital of Western Nepal: A cross-sectional study

BACKGROUND

Small for gestational age (SGA) is common among newborns in low-income countries like Nepal and has higher immediate mortality and morbidities.

OBJECTIVES

To study the prevalence and prognostic factors of SGA babies in Western Nepal.

METHODS

A cross-sectional study (November 2016-October 2017) was conducted in a tertiary care hospital in Western Nepal. Socio-demographic, lifestyle factors including diet, and exposures including smoking and household air pollution in mothers who delivered newborns appropriate for gestational age (AGA), SGA and large for gestational age (LGA) were recorded. Logistic regression was carried out to find the odds ratio of prognostic factors after adjusting for potential confounders.

RESULTS

Out of 4000 delivered babies, 77% (n = 3078) were AGA, 20.3% (n = 813) were SGA and 2.7% (n = 109) were LGA. The proportion of female-SGA was greater in comparison to male-SGA (n = 427, 52.5% vs n = 386, 47.5%). SGA babies were born to mothers who had term, preterm, and postterm delivery in the following proportions 70.1%, 19.3%, and 10.6%, respectively. The average weight gain (mean ± SD) by mothers in AGA pregnancies was 10.3 ± 2.4 kg, whereas in SGA were 9.3 ± 2.4 kg. In addition to low socioeconomic status (OR 1.9, 95% CI 1.1, 3.2), other prognostic factors associated with SGA were lifestyle factors such as low maternal sleep duration (OR 5.1, CI 3.6, 7.4) and monthly or less frequent meat intake (OR 5.0, CI 3.2, 7.8). Besides smoking (OR 8.8, CI 2.1, 36.3), the other major environmental factor associated with SGA was exposure to household air pollution (OR 5.4, 4.1, 6.9) during pregnancy. Similarly, some of the adverse health conditions associated with a significantly higher risk of SGA were anemia, oligohydramnios, and gestational diabetes.

CONCLUSIONS

SGA is common in Western Nepal and associated with several modifiable prognostic factors.

Timing- and Dose-Specific Associations of Prenatal Smoke Exposure With Newborn DNA Methylation

INTRODUCTION

Fetal changes in DNA methylation may underlie associations of maternal smoking during pregnancy with adverse outcomes in children. We examined critical periods and doses of maternal smoking during pregnancy in relation to newborn DNA methylation, and associations of paternal smoking with newborn DNA methylation.

AIMS AND METHODS

This study was embedded in the Generation R Study, a population-based prospective cohort study from early pregnancy onwards. We assessed parental smoking during pregnancy using questionnaires. We analyzed associations of prenatal smoke exposure with newborn DNA methylation at 5915 known maternal smoking-related cytosine-phosphate-guanine sites (CpGs) in 1261 newborns using linear regression. Associations with false discovery rate-corrected p-values < .05 were taken forward.

RESULTS

Sustained maternal smoking was associated with newborn DNA methylation at 1391 CpGs, compared with never smoking. Neither quitting smoking early in pregnancy nor former smoking was associated with DNA methylation, compared with never smoking. Among sustained smokers, smoking ≥5, compared with <5, cigarettes/d was associated with DNA methylation at seven CpGs. Paternal smoking was not associated with DNA methylation, independent of maternal smoking status.

CONCLUSIONS

Our results suggest that CpGs associated with sustained maternal smoking are not associated with maternal smoking earlier in pregnancy or with paternal smoking. Some of these CpGs show dose-response relationships with sustained maternal smoking. The third trimester may comprise a critical period for associations of smoking with newborn DNA methylation, or sustained smoking may reflect higher cumulative doses. Alternatively, maternal smoking limited to early pregnancy and paternal smoking may be associated with DNA methylation at specific other CpGs not studied here.

IMPLICATIONS

Our results suggest that quitting maternal smoking before the third trimester of pregnancy, and possibly lowering smoking dose, may prevent differential DNA methylation in the newborns at CpGs associated with sustained smoking. If the relevance of DNA methylation for clinical outcomes is established, these results may help in counseling parents-to-be about quitting smoking.

The effect of active and passive maternal smoking before and during pregnancy on neonatal weight at birth

INTRODUCTION

Smoking during pregnancy is a risk factor for adverse pregnancy outcomes. Data on the correlation between passive maternal smoking and pregnancy outcomes remain limited. We investigated the effect of active smoking and environmental tobacco smoke (ETS) during pregnancy on neonatal birthweight, including the risk for low birthweight (LBW).

MATERIAL AND METHODS

The study was conducted between 2010 and 2012. A group of 8625 women were surveyed during postpartum hospitalization. Outcome measures included mean birthweight of newborns. Additionally, odds ratios with confidence intervals were calculated to investigate the risk for LBW in active and passive smoking groups of mothers.

RESULTS

Lower birthweight (46 g - 307 g; p < 0.05) and a higher risk for LBW (OR = 1.35, 95% CI: 1.05-1.75; p < 0.05) were observed in all infants born to smoking mothers. A negative effect of ETS in pregnancy on the reduction of mean birthweight was also found. Additionally, we analyzed the cumulative effect of active and passive smoking on neonatal birthweight. A statistically significant reduction in neonatal weight at birth was found in a group of women who smoked actively and passively during pregnancy (130 g; p < 0.05).

CONCLUSIONS

Smoking is associated with decreased birthweight and in a group of active smoking mothers increased risk for LBW. This effect is dose-dependent and is also present in a group of women who smoked before pregnancy. There is also a cumulative effect of active smoking and ETS causing decreased neonatal birthweight and increased risk for low birthweight.

Exposure to psychosocial work strain and changes in smoking behavior during pregnancy - a longitudinal study within the Danish National Birth Cohort

Objective:

Knowledge of the relationship between psychosocial strain in the work environment and smoking during pregnancy is scarce. This study aimed to examine the association between psychosocial job strain and change in smoking behavior during pregnancy.

Methods:

The cohort included 65 645 pregnancies from the Danish National Birth Cohort (1996–2002), where pregnant women were interviewed on job factors and lifestyle during the first and third trimesters. Smoking was categorized into non-, non-daily, and daily smoking at each interview. Psychosocial job strain was categorized into four groups based on the concept of Karasek’s demand–control model: low strain (reference), passive, active and high strain. Associations between psychosocial strain and change in smoking status between the first and second interviews were analyzed by multinomial logistic regression, separately for each smoking category at first interview.

Results:

Non-smoking women exposed to high strain work were more likely to become daily smokers [adjusted odds ratio (OR_adj) 1.41, (95% confidence interval (CI) 1.08–1.83)] compared to non-smoking women exposed to low strain work. Non-smoking women exposed to passive work were more likely to become both non-daily and daily smokers [OR_adj 1.59 (95% CI 1.21–2.08) and OR_adj 1.32 (95% CI 1.03–1.70), respectively]. Daily smoking women exposed to high strain work were less likely to decrease their smoking [OR_adj 0.57 (95% CI 0.32–0.99)] compared to daily smoking women exposed to low strain work.

Conclusions:

Psychosocial strain influenced the women’s smoking behavior during pregnancy, especially in job types with low control.

Abnormal placental DNA methylation variation in spontaneous preterm birth

OBJECTIVE

Preterm birth (PTB) has become a major public health concern as the leading cause of neonatal death, but little is understood about its etiology. Children born preterm are also at increased risk of long-term consequences such as neurodevelopmental disorders, adulthood hypertension and diabetes. Recent studies have indicated that DNA methylation may be involved in the occurrence of PTB as well as related adverse outcomes. The latest Infinium EPIC BeadChip extends the coverage of the genome and provides a better tool to help investigate the involvement of DNA methylation in these conditions.

METHODS

We conducted this case-control study in three Women and Children's hospitals in South China, and enrolled 32 spontaneous preterm births and 16 term births. We assessed placental DNA methylation profiling of these participants with the Infinium EPIC BeadChip. We identified PTB and gestational age (GA)-associated CpG sites with limma regression model, and applied seqlm to identify PTB-associated regions. We performed gene ontology analysis to further interpret functional enrichment of the identified differentially methylated genes in PTB.

RESULTS

We identified a total of 8 differentially methylated positions (DMPs) that were significantly associated with PTB (FDR < 0.1) and a total of 15 DMPs that were associated with GA (FDR < 0.1). In the regional analysis, one differentially methylated region in the SLC23A1 gene overlapped with PTB-associated CpG site. The differentially methylated CpG sites in PTB were mapped to the genes involving in biological processes mainly regarding neurodevelopment, regulation of inflammation and metabolism.

CONCLUSION

Our findings suggested that preterm placenta have distinct DNA methylation alterations, and these alteration patterns established at birth provide insight into the long-term consequences of preterm birth.

Impact of smoking and fetal gender on preterm delivery

According to the World Health Organization, smoking is the most important risk factor for adverse pregnancy outcomes in industrialized nations. We aimed to establish how fetal gender and smoking interact with regard to perinatal outcomes, especially preterm delivery. Data from 220,339 singleton pregnancies, obtained from the German Perinatal Survey in Schleswig-Holstein and registered between 2004 and 2017 were analyzed in regard to smoking behavior, fetal gender, and preterm delivery. The rate of preterm births was directly proportional to the women's consumption of nicotine. The rate of preterm deliveries was 6.8% among nonsmokers, and 13.2% in women who were very heavy smokers (≥22 cigarettes/day). Very heavy smoking (≥22 cigarettes/day) had a marked impact on extremely preterm births (<28 weeks of gestation) and very preterm births (28-31 weeks of gestation). Preterm births increased by 1.2% from heavy smokers to very heavy smokers; the differences between the other groups ranged between 0.1% and 0.4%. Fetal gender also had an impact on preterm birth: male infants were predominant in nearly all groups of women who delivered preterm infants. Smoking during pregnancy and male gender are both risk factors for preterm delivery. Fetal gender should be given greater attention as one of the several risk factors of preterm birth. Due to the high rate of morbidity among preterm infants and enormous costs for the healthcare system, women should be encouraged to cease or at least reduce smoking during pregnancy.

Fetal Growth Restriction in Hypertensive vs. Heavy Smoking Women-Placental Pathology, Ultrasound Findings, and Pregnancy Outcomes

We compared placental pathology, ultrasonographic findings, and obstetric outcomes, in gestations complicated by fetal growth restriction (FGR) with either a background of hypertensive disorder or heavy tobacco cigarette smoking. The medical records and placental pathology reports of pregnancies complicated with FGR (birthweight < 10th percentile) between December 2008 and May 2018 from a single tertiary center were reviewed. Placental pathology, ultrasound findings, and pregnancy outcomes were compared between hypertensive patients (HTN) and heavy smokers (SMO). We included 213 pregnancies: 129 (60.6%) in the SMO group and 84 (39.4%) in the HTN group. The HTN group was characterized by a higher BMI (p = 0.01), higher rates of Cesarean deliveries (p = 0.006), and a lower gestational age at delivery (35.6 ± 3.8 vs. 37.5 ± 2.9 weeks, p < 0.001). The HTN group had higher rates of placental weights < 10th percentile (p = 0.04) and maternal vascular malperfusion lesions (p < 0.001), while the SMO group had higher rates of inflammatory lesions (p = 0.04). On ultrasound, the HTN group had a higher head/abdomen circumference ratio (p < 0.001) and more abnormal Doppler studies (< 0.001). Neonates in the HTN group had lower birthweights (p < 0.001) and higher rates of NICU admissions (p = 0.002) and adverse neonatal outcome (p = 0.006). On multivariable analysis, gestational age at delivery (aOR = 0.65, 95%CI 0.55-0.87), hypertensive disorders (aOR = 1.8, 95%CI = 1.21-4.81), placental MVM lesions (aOR = 1.23, 95%CI = 1.08-5.02), and the combination of HTN+MVM (aOR = 2.63, 95%CI 1.78-7.30) were independently associated with adverse neonatal outcome. Hypertension and smoking may lead to FGR in different pathways as the two groups significantly differed in maternal characteristics, placental pathology, ultrasound findings, and neonatal outcomes. A hypertensive disorder probably represents a more hostile maternal environment than smoking and these pregnancies would probably benefit from closes monitoring.

The Effects of Different Smoking Patterns in Pregnancy on Perinatal Outcomes in the Southampton Women's Survey

Maternal smoking during pregnancy has established associations with poor perinatal outcomes. Among continuing pregnant smokers, harm-reduction strategies have been suggested, including temporary cessation of smoking during pregnancy, also known as partial quitting. Support for this strategy, however, remains limited. Six hundred and ninety-seven women in the Southampton Women's Survey who smoked at their last menstrual period were categorised into sustained quitters, partial quitters (quit in either the first or third trimester but not both) or sustained smokers (continued to smoke throughout pregnancy). In regression models, compared with infants born to sustained smokers, infants born to sustained quitters and partial quitters were heavier at birth by β = 0.64 standard deviations (SD) (WHO z-score) (95% CI: 0.47-0.80) and 0.48 SD (WHO z-score) (95% CI: 0.24-0.72) respectively, adjusted for confounders, with similar patterns seen for other anthropometric measures (head circumference and crown-heel length). Sustained quitters had longer gestations by β = 3.5 days (95% CI: 1.8-5.2) compared with sustained smokers, but no difference was seen for partial quitters. While sustained quitting remains the most desired outcome for pregnant smokers, partial quitting should be explored as a strategy to reduce some of the harmful effects of smoking on offspring in those who cannot achieve sustained quitting.

Risk stratification for small for gestational age for the Brazilian population: a secondary analysis of the Birth in Brazil study

Risk-stratification screening for SGA has been proposed in high-income countries to prevent perinatal morbidity and mortality. There is paucity of data from middle-income settings. The aim of this study is to explore risk factors for SGA in Brazil and assess potential for risk stratification. This population-based study is a secondary analysis of Birth in Brazil study, conducted in 266 maternity units between 2011 and 2012. Univariate and multivariate logistic regressions were performed, and population attributable fraction estimated for early and all pregnancy factors. We calculated absolute risk, odds ratio, and population prevalence of single or combined factors stratified by parity. Factors associated with SGA were maternal lupus (OR_adj 4.36, 95% CI [2.32-8.18]), hypertensive disorders in pregnancy (OR_adj 2.72, 95% CI [2.28-3.24]), weight gain < 5 kg (OR_adj 2.37, 95% CI [1.99-2.83]), smoking at late pregnancy (OR_adj 2.04, 95% CI [1.60-2.59]), previous low birthweight (OR_adj 2.22, 95% CI [1.79-2.75]), nulliparity (OR_adj 1.81, 95% CI [1.60-2.05]), underweight (OR_adj 1.61, 95% CI [1.36-1.92]) and socioeconomic status (SES) < 5th centile (OR_adj 1.23, 95% CI [1.05-1.45]). Having two or more risk factors (prevalence of 4.4% and 8.0%) was associated with a 2 and fourfold increase in the risk for SGA in nulliparous and multiparous, respectively. Early and all pregnancy risk factors allow development of risk-stratification for SGA. Implementation of risk stratification coupled with specific strategies for reduction of risk and increased surveillance has the potential to contribute to the reduction of stillbirth in Brazil through increased detection of SGA, appropriate management and timely delivery.

Are antenatal interventions effective in improving multiple health behaviours among pregnant women? A systematic review protocol

BACKGROUND

Maternal behaviours in pregnancy associated with adverse pregnancy, birth and health outcomes include tobacco smoking, poor nutrition, alcohol consumption and low physical activity, collectively referred to as the SNAP risk factors. Due to the high prevalence, co-occurrence and possible interactive health effects of such health behaviours in pregnancy, antenatal interventions that support pregnant women to improve multiple SNAP behaviours have a greater potential impact on the health outcomes of women and their children than interventions addressing single behaviours. The objective of this review is to determine the effectiveness of interventions delivered as part of antenatal care that aim to improve multiple SNAP behaviours among pregnant women.

METHODS

Seven electronic databases will be searched for potentially eligible studies. Eligible studies will include those where pregnant women are attending antenatal care. Studies that examine the effect of an intervention that addresses multiple SNAP behaviours (≥ 2 behaviours) during pregnancy and are delivered or instigated through antenatal care in a healthcare service will be included. Systematic reviews of randomised controlled trials (RCTs), RCTs, cluster RCTs, stepped-wedge RCTs and non-randomised control trials will be eligible. Studies that include a no-intervention control, wait-list control group, standard/usual care, or another active single behavioural intervention (e.g. addressing one behaviour only) will be considered. Two independent reviewers will conduct study screening, data extraction and risk of bias assessment. Discrepancies will be resolved by consensus or a third reviewer if required. A random effects model will be used to synthesise the results. Alternative synthesis methods will be investigated in instances where a meta-analysis is not appropriate, such as summarising effect estimates, combining P values, vote counting based on direction of effect, or synthesis in narrative form.

DISCUSSION

The review will synthesise the evidence on the effect of interventions that address multiple SNAP behaviours in antenatal care and will help researchers, policy-makers and health services to develop and deliver best practice integrated models of antenatal care that have the potential to impact on both the short- and long-term health outcomes for women and their children.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018095315.

Maternal cigarette smoking before and during pregnancy and the risk of preterm birth: A dose-response analysis of 25 million mother-infant pairs

BACKGROUND

Most of the women who smoke before pregnancy continue smoking during pregnancy, and some start to quit smoking after being pregnant, although existing guidelines for pregnancy recommend that women who smoke should quit smoking before pregnancy. Findings about the timing and intensity of maternal smoking, especially low-intensity smoking (1-9 cigarettes per day), and preterm birth are still inconsistent and ambiguous. This study aimed to examine the association of the timing of smoking and doses of smoking before pregnancy and during the first or second trimester of pregnancy with preterm birth in a large-scale population-based retrospective cohort study.

METHODS AND FINDINGS

We used nationwide birth certificate data from singleton mother-infant pairs in the United States National Vital Statistics System, 2011-2018. All adult women with live singleton births, without preexisting hypertension or diabetes, and with complete data on smoking and gestational age at delivery were included. Participants reported their smoking status (yes or no) and daily number of cigarettes consumed before and during each trimester of pregnancy. The outcome of interest was preterm birth, defined as a birth before 37 weeks of gestation. Logistic regression models were used to estimate the odds ratio (OR) with 95% confidence intervals (CIs) of preterm birth associated with smoking status and the number of cigarettes consumed, adjusting for maternal age, race/ethnicity, parity, education levels, prepregnancy BMI, previous history of preterm birth, marital status, infant sex, and initiation of prenatal care. This study included 25,623,479 women, with a mean age of 29 years (range 20-50 years); 13,742,486 (53.6%) participants were of non-Hispanic white ancestry, 5,971,598 (23.3%) of Hispanic ancestry, and 3,417,456 (13.34%) of non-Hispanic black ancestry. The prevalence of preterm birth was 9.3% (n = 2,378,398). We found that maternal smoking during pregnancy, even at a very low level of intensity, was associated with an increased risk of preterm delivery. The adjusted ORs (95% CI) of preterm birth for mothers who smoked 1-2, 3-5, 6-9, 10-19, and ≥20 cigarettes per day during the first trimester compared with mothers who did not smoke were 1.31 (1.29-1.33), 1.31 (1.30-1.32), 1.33 (1.31-1.35), 1.44 (1.43-1.45), and 1.53 (1.52-1.55), respectively (all P values < 0.001), whereas for those who smoked during the second trimester, the corresponding ORs were 1.37 (1.35-1.39), 1.36 (1.35-1.38), 1.36 (1.34-1.38), 1.48 (1.47-1.49), and 1.59 (1.58-1.61), respectively (all P values < 0.001). Furthermore, smokers who quit before pregnancy, regardless of smoking intensity, had a comparable risk of preterm birth with nonsmokers, although this was not the case when cessation occurred in the first or second trimester of pregnancy. The major limitation of this study is the self-reported information about smoking, which may be subject to information bias. In addition, we cannot rule out the possibility of residual confounding caused by unmeasured factors in an observational research design.

CONCLUSIONS

In this study, we observed that low-intensity cigarette consumption during either the first or second trimester of pregnancy, even as low as 1-2 cigarettes per day, was associated with an increased risk of preterm birth. These findings suggest that there is no safe level or safe trimester for maternal smoking during pregnancy. Women of reproductive age who smoke should be strongly encouraged and supported to quit smoking before pregnancy.

Folic acid supplementation is associated with size at birth in the Screening for Pregnancy Endpoints (SCOPE) international prospective cohort study

BACKGROUND

Small-for-gestational-age (SGA) is a significant cause of morbidity and mortality, and there are currently few preventive strategies.

AIM

The aim of this study was to investigate the relationship between maternal folic acid supplement (FAS) use pre-conception through to the second trimester, and small-for-gestational age (SGA) and birth size parameters.

STUDY DESIGN

Women were recruited as part of the Screening for Pregnancy Endpoints (SCOPE) international prospective multi-centre cohort study: New Zealand, Australia, United Kingdom and Ireland. Information on FAS use pre-conception, during the first trimester and at 15 ± 1 weeks' gestation was collected via interview administered questionnaire. Participants were followed through to delivery. Pregnancy outcome data and birth measurements were collected within 72 h of birth. Multivariable regression analysis was used to investigate relationships between FAS and outcomes, adjusting for maternal sociodemographic and lifestyle factors.

SUBJECTS

Nulliparous women with singleton pregnancies.

OUTCOME MEASURES

SGA (<10th customised birthweight centile).

RESULTS

5606 women were included. SGA prevalence was 11.3%. Pre-conception FAS was associated with a significantly lower risk of SGA: aOR = 0.82 (95% CI: 0.67-01.00 p = 0.047). Although the association between FAS at 15 weeks' gestation and SGA did not reach significance, FAS at 15 weeks was associated with a significantly higher customised birthweight centile (β 2.56 (95% CI: 0.87-4.26; p = 0.003). There was no significant effect of FAS on large-for-gestational-age births or head circumference.

CONCLUSIONS

In this international cohort, FAS was positively associated with fetal growth, without increasing risks associated with LGA. Further studies are required to confirm whether continuing FAS beyond the first trimester might lower the risk of SGA.

Changes in parental smoking during pregnancy and risks of adverse birth outcomes and childhood overweight in Europe and North America: An individual participant data meta-analysis of 229,000 singleton births

BACKGROUND

Fetal smoke exposure is a common and key avoidable risk factor for birth complications and seems to influence later risk of overweight. It is unclear whether this increased risk is also present if mothers smoke during the first trimester only or reduce the number of cigarettes during pregnancy, or when only fathers smoke. We aimed to assess the associations of parental smoking during pregnancy, specifically of quitting or reducing smoking and maternal and paternal smoking combined, with preterm birth, small size for gestational age, and childhood overweight.

METHODS AND FINDINGS

We performed an individual participant data meta-analysis among 229,158 families from 28 pregnancy/birth cohorts from Europe and North America. All 28 cohorts had information on maternal smoking, and 16 also had information on paternal smoking. In total, 22 cohorts were population-based, with birth years ranging from 1991 to 2015. The mothers' median age was 30.0 years, and most mothers were medium or highly educated. We used multilevel binary logistic regression models adjusted for maternal and paternal sociodemographic and lifestyle-related characteristics. Compared with nonsmoking mothers, maternal first trimester smoking only was not associated with adverse birth outcomes but was associated with a higher risk of childhood overweight (odds ratio [OR] 1.17 [95% CI 1.02-1.35], P value = 0.030). Children from mothers who continued smoking during pregnancy had higher risks of preterm birth (OR 1.08 [95% CI 1.02-1.15], P value = 0.012), small size for gestational age (OR 2.15 [95% CI 2.07-2.23], P value < 0.001), and childhood overweight (OR 1.42 [95% CI 1.35-1.48], P value < 0.001). Mothers who reduced the number of cigarettes between the first and third trimester, without quitting, still had a higher risk of small size for gestational age. However, the corresponding risk estimates were smaller than for women who continued the same amount of cigarettes throughout pregnancy (OR 1.89 [95% CI 1.52-2.34] instead of OR 2.20 [95% CI 2.02-2.42] when reducing from 5-9 to ≤4 cigarettes/day; OR 2.79 [95% CI 2.39-3.25] and OR 1.93 [95% CI 1.46-2.57] instead of OR 2.95 [95% CI 2.75-3.15] when reducing from ≥10 to 5-9 and ≤4 cigarettes/day, respectively [P values < 0.001]). Reducing the number of cigarettes during pregnancy did not affect the risks of preterm birth and childhood overweight. Among nonsmoking mothers, paternal smoking was associated with childhood overweight (OR 1.21 [95% CI 1.16-1.27], P value < 0.001) but not with adverse birth outcomes. Limitations of this study include the self-report of parental smoking information and the possibility of residual confounding. As this study only included participants from Europe and North America, results need to be carefully interpreted regarding other populations.

CONCLUSIONS

We observed that as compared to nonsmoking during pregnancy, quitting smoking in the first trimester is associated with the same risk of preterm birth and small size for gestational age, but with a higher risk of childhood overweight. Reducing the number of cigarettes, without quitting, has limited beneficial effects. Paternal smoking seems to be associated, independently of maternal smoking, with the risk of childhood overweight. Population strategies should focus on parental smoking prevention before or at the start, rather than during, pregnancy.

Parenthood and smoking

Parents' smoking is harmful to infants' health. While it is well established that the fraction of mothers smoking during pregnancy is non-negligible, it is an open question of how many parents actually quit smoking to account for the adverse health effects accruing to their offspring. It is also unknown for how long smoking is reduced after first childbirth. This paper investigates these questions in a longitudinal analysis. The analyzed time period covers smoking patterns several years before childbirth and up to twenty years afterwards. Women's smoking probability already drops several years before first childbirth and it remains reduced until the first child turns 18 years old. In the second and third trimester of pregnancy, the drop is largest by around 75 percent.

Smoking cessation in early-pregnancy, gestational weight gain and subsequent risks of pregnancy complications

OBJECTIVE

Smoking cessation is associated with weight gain. We first examined the associations of smoking cessation in early-pregnancy with gestational weight gain and subsequently evaluated the risks of pregnancy complications among women who quit smoking in early-pregnancy according to their gestational weight gain.

METHODS

In a population-based prospective cohort study among 7,389 women, we measured weight in each pregnancy period. Information on smoking and pregnancy complications was obtained from questionnaires and medical records.

RESULTS

As compared to continued smoking during pregnancy, smoking cessation in early-pregnancy was not associated with gestational weight gain. Smoking cessation in early-pregnancy was associated with decreased risks of delivering small-for-gestational-age infants (Odds Ratio (OR) 0.52 (95 % Confidence Interval (CI) 0.37, 0.75)), but with increased risks of pre-eclampsia (OR 2.07 (95 % CI 1.01, 4.27)) and delivering large-for-gestational-age infants (OR 2.11 (95 % CI 1.45, 3.09)). Among women who quit smoking in early-pregnancy with >12 kg weight gain, the risks of pre-eclampsia and delivering large-for-gestational-age infants were slightly increased.

CONCLUSION

As compared to continued smoking during pregnancy, smoking cessation in early-pregnancy is not associated with increased gestational weight gain. Among women who quit smoking in early-pregnancy, higher gestational weight gain does not strongly affect their risks of pregnancy complications.

Optical coherence tomography angiography to evaluate murine fetal brain vasculature changes caused by prenatal exposure to nicotine

Maternal smoking causes several defects ranging from intrauterine growth restriction to sudden infant death syndrome and spontaneous abortion. While several studies have documented the effects of prenatal nicotine exposure in development and behavior, acute vasculature changes in the fetal brain due to prenatal nicotine exposure have not been evaluated yet. This study uses correlation mapping optical coherence angiography to evaluate changes in fetal brain vasculature flow caused by maternal exposure to nicotine during the second trimester-equivalent of gestation in a mouse model. The effects of two different doses of nicotine were evaluated. Results showed a decrease in the vasculature for both doses of nicotine, which was not seen in the case of the sham group.

Low birthweight in term singletons mediates the association between maternal smoking intensity exposure status and immediate neonatal intensive care unit admission: the E-value assessment

BACKGROUND

Research investigating the wellbeing of term neonates in the United States is scarce. The objectives of this study were to estimate the prevalence of low birthweight (LBW) and neonatal intensive care unit (NICU) admission among term singletons in association with maternal smoking intensity exposure status, to explore LBW as a mediator linking smoking to immediate newborn NICU transfer/admission, and to assess the potential impact of unmeasured confounding in effect estimates.

METHODS

The Natality File of live births registered in the United States in 2016, the first year that all 50 states implemented the revised 2003 standard birth certificate, was restricted to singleton term births (37-41 completed weeks gestation). The prevalence of LBW (< 2500 g) and NICU transfer/admission was estimated across maternal demographic characteristics and smoking intensity status in early and in late pregnancy. Mediation analyses, based on the counterfactual approach, were conducted to examine the total effect (TE), controlled direct effect (CDE), natural direct (NDE) and indirect effects (NIE), and the percentage mediated through LBW. The E-values based on effect size estimates and on lower-bounds of 95% confidence intervals (CIs) assessed the potential impact of unmeasured confounding.

RESULTS

Nearly 6.8% of women smoked in early and in late pregnancy, most (36.4%) smoked at high intensity (≥ 10 cigarettes /day) and had the highest prevalence of LBW (6.7%) and NICU transfer/admission (7.0%). For the largest smoking intensity exposure category, the estimate of the TE was 1.68 (95% CI: 1.63, 1.73), of the NDE was 1.56 (95% CI: 1.51, 1.61), of the NIE was 1.08 (95% CI:1.07, 1.09), and the percentage mediated by LBW was 17.6%. The E-values for association estimates and for the lower-bounds of 95% CIs demonstrated the minimum strength of the potential unmeasured confounding necessary to explain away observed associations.

CONCLUSIONS

These findings fill a gap on the prevalence of LBW and NICU transfer/admission in term neonates of mothers who smoke and on the role of LBW linking to NICU placement, which could be used to update practitioners, to implement smoking cessation interventions, monitor trends, and to inform planning and allocation of healthcare resources.