The influence of maternal smoking and exposure to residential ETS on pregnancy outcomes: a retrospective national study

Effect of passive smoking on birth weight in pregnant women with vitamin D deficiency living in Turkey: A case control study

AIM

Although vitamin D deficiency in smokers has a greater risk of low birth weight than vitamin D deficiency or smoking alone, there is no study searching birth weight in vitamin D deficient passive smokers. We evaluated the effect of vitamin D deficiency on birth weight in active and passive smokers. Additionally, we aimed to determine the predictive role of vitamin D for low birth weight in smokers.

METHODS

The study was designed as a retrospective case control study. A total of 210 participants were divided into three groups: active smoking (n = 34), passive smoking (n = 79), and non-smokers (n = 97). Then passive smokers were divided into two subgroups as vitamin D ≥ 20 ng/mL (n = 23) and vitamin D < 20 ng/mL (n = 56). Sociodemographic, laboratory, and perinatal characteristics were recorded and compared between groups.

RESULTS

Birth weight was higher in non-smokers as compared to active (p < 0.001) and passive (p = 0.001) smokers, and also in passive than active smokers (p = 0.023). In passive smokers, birth weight was lower in vitamin D < 20 ng/mL group (p < 0.001). Vitamin D were correlated with birth weight in all smokers (r = 0.653, p < 0.001), passive (r = 0.624, p < 0.001) and active smokers (r = 0.526, p = 0.001). Vitamin D ≤ 14 ng/mL predicted low birth weight with 100% sensitivity and 53.92% specificity in smokers (area under curve [AUC] = 0.773, p < 0.001), with 100% sensitivity and 63.5% specificity in passive smokers (AUC = 0.759, p < 0.001) while vitamin D ≤ 11 ng/mL predicted with 83.33% sensitivity and 71.43% specificity in active smokers (AUC = 0.774, p = 0.008).

CONCLUSION

Vitamin D deficiency in smokers is associated with low birth weight. Although vitamin D supplementation is not routinely recommended in pregnant women, we suggest that it could be an option in preventing low birth weight in smokers, even passive ones, who do not have adequate dietary intake and have insufficient exposure to daylight.

Risk of Gestational Diabetes Due to Maternal and Partner Smoking

Pregnant women are among the most vulnerable to environmental exposure to tobacco smoke (EET); which has been linked to problems in the mothers’ health; one of the most frequent is gestational diabetes (GD). For this reason, there are specific interventions and prevention strategies designed to reduce this exposure risk. However, currently, they are mostly aimed only at aiding the pregnant women with smoking cessation during pregnancy and do not assess or address the risk from passive exposure due to partner smoking. The aim of this work is to study the exposure to EET of pregnant women considering active and passive smoking and to evaluate its effect on the development of GD. This is an observational case-control study within a retrospective cohort of pregnant women. Information on smoking habits was obtained from both personal interviews and recorded medical history. In total, 16.2% of mothers and 28.3% of partners declared having been active smokers during pregnancy; 36.5% of the women presented EET during pregnancy when both active and passive smoking were considered. After adjustments, the association with the EET and GD of the mother was (aOR 1.10 95% CI: 0.64–1.92); for the EET of the partner, it was (aOR 1.66 95% CI: 1.01–2.77); for both partners, it was (aOR 1.82 95% CI: 1.15–2.89), adjusted by the mother’s age and body mass index. There is a lack of education regarding the effects of passive exposure to tobacco smoke. It is essential that pregnant women and their partners are educated on the risks of active and passive smoking; this could improve the effectiveness of other GD prevention strategies.

Obstetrical and Neonatal Outcomes of 3,028 Singletons Born After Advanced ART Techniques: Ejaculated Sperm Intracytoplasmic Sperm Injection, Artificial Oocyte Activation, in Vitro Maturation and Testicular Sperm Extraction

Background: To evaluate obstetrical and neonatal outcomes of singletons conceived after advanced assisted reproductive technology (ART) techniques: conventional IVF pregnancies (C-IVF), ejaculated sperm intracytoplasmic sperm injection (ICSI), assisted oocyte activation (AOA), in vitro maturation (IVM), and testicular sperm extraction (TESE).

Methods: The subjects were 3,028 singletons who were born after fresh or frozen embryo transfer. The subjects were separated into five groups: C-IVF (n = 855), ICSI (n = 1,869), AOA (n = 42), IVM (n = 32), and TESE (n = 230). We evaluated obstetrical and neonatal outcomes calculating the adjusted odds ratio (AOR) using multivariable logistic regression analyses for fresh and frozen embryos and for cleavage and blastocyst transfer. The C-IVF group was used as a background control for the ICSI group. Moreover, the TESE, AOA, and IVM groups were compared to the ICSI group to evaluate the effects of the ICSI procedure itself.

Results: The incidence of perinatal complications was significantly lower in the ICSI-fresh group (AOR = 0.29, 95% CI: 0.10–0.83, p ¡ 0.05). Regarding sex ratio, the IVM was significantly associated with sex ratio imbalance toward female in both fresh and frozen groups (AOR = 0.30, 95% CI: 0.10–0.96, AOR = 0.27, 95% CI: 0.07–0.98, p ¡ 0.05). On the other hand, there were no significant differences in preterm birth rate, low birth weight rate and congenital abnormalities rate between conventional IVF, ICSI, and the other groups.

Conclusions: There were no negative effects on obstetrical and neonatal outcomes between conventional IVF and ICSI. Although this was a limited sample size study, advanced ART technologies such as AOA, IVM, and TESE also seem to have a low risk of adverse impact on obstetrical and neonatal outcomes but may have a slight impact on sex ratio.

Exposure assessment of indoor particulate matter during pregnancy: a narrative review of the literature

OBJECTIVE

The aim of this review was to summarize the evidence of the exposure assessment approaches of indoor particulate matter (PM) during pregnancy and to recommend future focus areas.

CONTENT

Exposure to indoor PM during pregnancy is associated with adverse birth outcomes. However, many questions remain about the consistency of the findings and the magnitude of this effect. This may be due to the exposure assessment methods used and the challenges of characterizing exposure during pregnancy. Exposure is unlikely to remain constant over the nine-month period. Pregnant females' mobility and activities vary - for example, employment status may be random among females, but among those employed, activities are likely to be greater in the early pregnancy than closer to the delivery of the child.

SUMMARY

Forty three studies that used one of the five categories of indoor PM exposure assessment (self-reported, personal air monitoring, household air monitoring, exposure models and integrated approaches) were assessed. Our results indicate that each of these exposure assessment approaches has unique characteristics, strengths, and weaknesses. While questionnaires and interviews are based on self-report and recall, they were a major component in the reviewed exposure assessment studies. These studies predominantly used large sample sizes. Precision and detail were observed in studies that used integrated approaches (i. e. questionnaires, measurements and exposure models).

OUTLOOK

Given the limitations presented by these studies, exposure misclassification remains possible because of personal, within and between household variability, seasonal changes, and spatiotemporal variability during pregnancy. Therefore, using integrated approaches (i. e. questionnaire, measurements and exposure models) may provide better estimates of PM levels across trimesters. This may provide precision for exposure estimates in the exposure-response relationship.

Influence of Environmental Tobacco Smoke and Air Pollution on Fetal Growth: A Prospective Study

Exposure to air pollution during pregnancy leads to adverse pregnancy outcomes. Few studies have evaluated the influences of air quality, including environmental tobacco smoke (ETS) and particulate matter (PM), on fetal development, which this study examined. This longitudinal correlation study used multiple linear regression data analysis of PM_2.5/PM₁₀, self-reported ETS exposure, urinary cotinine level, maternal characteristics, and birth parameters (gestational week, body weight, body length, head, and chest circumferences) with the effect of air quality on fetal growth. The study included 74 pregnant women (mean age 31.9 ± 4.2 years, body mass index 23.6 ± 3.8 kg/m², average gestational duration 38.5 ± 0.8 weeks). ETS exposure decreased birth length by ≥1 cm, and potentially is an independent risk factor for fetal growth restriction, and pregnant women should avoid indoor and outdoor ETS. However, neither PM_2.5/PM₁₀ nor ETS was associated with low birth weight or small for gestational age. This study adds to the evidence base that ETS exposure of nonsmoking pregnant women affects the fetal birth length. Family members should refrain from smoking near expectant mothers, although smoking in the vicinity of their residential surroundings potentially exposes mothers and their fetuses to ETS. Public pollution and childbirth education classes should include details of indoor ETS.

Trends and Causes of Neonatal Mortality in Serbia, 1997-2016

Background

Regardless of the notable reduction in infant deaths worldwide over the last 30 years, the proportion of neonatal mortality in total child mortality is increasing.

Aims

To perform a trend analysis of neonatal mortality in Serbia.

Study Design

Descriptive observational study.

Methods

Joinpoint regression was used to analyze neonatal mortality data for the years 1997 to 2016 that were obtained from the Statistical Office of Serbia.

Results

The trend in the neonatal mortality rate decreased significantly by -5.6% (95% CI: -6.5 to -4.6) per year from 1997 to 2007, and by -2.6% (95% CI: -3.7 to -1.5) per year from 2007 to 2016. The neonatal mortality rate for certain conditions originating in the perinatal period decreased by -6.2% (95% CI: -7.5 to -4.9) per year during the years from 1997 to 2006, and by -1.9% (95% CI: -3.1 to -0.7) per year from 2006 to 2016. Among these conditions, disorders related to short gestation and low birth weight, not elsewhere classified, showed an upward trend by 8.5% (95% CI: 6.2 to 10.8) per year during the entire study period. From 1997 to 2016, a significant decrease in the neonatal mortality rate was detected in cases of congenital malformations, deformations, and chromosomal abnormalities, by -5.0% (95% CI: -6.1 to -4.0) per year. The neonatal mortality rate for cases of symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified, decreased by -8.1% (95% CI: -11.0 to -5.2) yearly.

Conclusion

The neonatal mortality rate in Serbia decreased between 1997 and 2016, excluding deaths due to short gestation and low birth weight. Therefore, prevention of short gestation and low birth weight should be the highest public priority.

Exposures to chemical mixtures during pregnancy and neonatal outcomes: The HOME study

INTRODUCTION

Exposure to mixtures of environmental chemicals are prevalent among pregnant women and may be associated with altered fetal growth and gestational age. To date, most research regarding environmental chemicals and neonatal outcomes has focused on the effect of individual agents.

METHODS

In a prospective cohort of 380 pregnant women from Cincinnati, OH (enrolled 2003-2006), we used biomarkers to estimate exposure to 43 phenols, phthalates, metals, organophosphate/pyrethroid/organochlorine pesticides, polychlorinated biphenyls, polybrominated diphenyl ethers, perfluoroalkyl substances (PFAS), and environmental tobacco smoke. Using three approaches, we estimated covariate-adjusted associations of chemical mixtures or individual chemicals with gestational-age-specific birth weight z-scores, birth length, head circumference, and gestational age: k-means clustering, principal components (PC), and one-chemical-at-a-time regression.

RESULTS

We identified three chemical mixture profiles using k-means clustering. Women in cluster 1 had higher concentrations of most phenols, three phthalate metabolites, several metals, organophosphate/organochlorine pesticides, polychlorinated biphenyls, and several PFAS than women in clusters 2 and 3. On average, infants born to women in clusters 1 (-1.2 cm; 95% CI: -1.9, -0.5) and 2 (-0.5 cm; 95% CI: -1.1, 0.1) had lower birth length than infants in cluster 3. Six PCs explained 50% of the variance in biomarker concentrations and biomarkers with similar chemical structures or from shared commercial/industrial settings loaded onto commons PCs. Each standard deviation increase in PC 1 (organochlorine pesticides, some phenols) and PC 6 (cadmium, bisphenol A) was associated with 0.2 cm (95% CI: -0.4, 0.0) and 0.1 cm (95% CI: -0.4, 0.1) lower birth length, respectively. Organochlorine compounds, parabens, and cadmium were inversely associated with birth length in the one-chemical-at-a-time analysis. Cluster membership, PC scores, and individual chemicals were not associated with other birth outcomes.

CONCLUSION

All three methods of characterizing multiple chemical exposures in this cohort identified inverse associations of select organochlorine compounds, phenols, and cadmium with birth length, but not other neonatal outcomes.

Prenatal Secondhand Smoke Exposure: Correlation Between Nicotine in Umbilical Cord Blood and Neonatal Anthropometry

Objectives

Nicotine narrows uterine blood vessels reducing the flow of oxygen and nutrients to the developing fetus. This study examined the effects of fetal exposure to secondhand smoke on neonatal anthropometry.

Methods

This cross sectional study recruited 128 pregnant women in the third trimester of single pregnancies who had no chronic illness, were not active or ex-smokers, and who were willing to participate in the study. Pregnant women who were exposed to secondhand smoke had umbilical cord blood nicotine concentrations of ≥ 1 ng/mL. Neonatal anthropometry was assessed according to the newborn birth weight and length. The independent t-test was used to determine the neonatal difference in mean birth weight and length between the women who were exposed to secondhand smoke, and those who were not exposed. A multiple linear regression analysis was employed to assess the effect of secondhand smoke exposure on birth weight and birth length, controlling for potential confounding variables (weight gain during pregnancy, body mass index, parity, maternal age, and maternal hemoglobin).

Results

There were 35 women exposed to secondhand smoke (nicotine ≥ 1 ng/mL). Neonate birth weight and birth length were lower among mothers who were exposed to secondhand smoke. However, only neonate birth weight was significantly reduced by exposure to secondhand smoke (p = 0.005). The mean birth weight of these neonates was 2,916.5 g ± 327.3 g which was 205.6 g less than in unexposed fetuses.

Conclusion

Exposure of mothers to secondhand smoke during pregnancy reduces fetal development and neonatal weight.

Appetite during the second and third trimesters mediates the impact of prenatal environmental tobacco smoke exposure on symmetric full-term low birth weight

Objective: To examine the relationship of prenatal environmental tobacco smoke (ETS) exposure and full-term low birth weight (FT-LBW) when taking anthropometric proportionality into consideration, and explore whether appetite mediates their association.Study design: We conducted a case-control study among pregnant women at two Women and Children's Hospitals in Guangdong, China. Information was collected through interview and medical records review. A series of logistic and linear regressions were used to examine the relationships of prenatal ETS exposure, appetite, and FT-LBW.Results: After adjusting for the potential confounders, prenatal ETS exposure was significantly negatively associated with FT-LBW (OR: 1.83, 95%CI: 1.35-2.48) and negatively correlated with maternal appetite in second and third trimester during pregnancy (β: -0.11, standard error: 0.03). Moreover, mediation analysis illustrated that maternal appetite partially mediated 12.00% of their relationship. However, subgroup analysis showed that prenatal ETS exposure was linked to higher risk of symmetric FT-LBW (OR: 2.26, 95%CI: 1.56-3.26) but not asymmetric FT-LBW. And maternal appetite explained only 6.45% of their relationship.Conclusions: Maternal prenatal ETS exposure increased risk of having symmetric FT-LBW infant, and appetite might mediate their relationship partially. This study emphasizes the importance of sample homogeneity and stresses the needs to improve the public awareness of the harmful effects of ETS.

Accuracy of birth certificate head circumference measurements: Massachusetts, 2012-2013

BACKGROUND

Zika virus has recently emerged as a novel cause of microcephaly. CDC has asked states to rapidly ascertain and report cases of Zika-linked birth defects, including microcephaly. Massachusetts added head circumference to its birth certificate (BC) in 2011. The accuracy of head circumference measurements from state vital records data has not been reported.

METHODS

We sought to assess the accuracy of Massachusetts BC head circumference measurements by comparing them to measurements for 2,217 infants born during 2012-2013 captured in the Massachusetts Birth Defects Monitoring Program (BDMP) data system. BDMP contains information abstracted directly from infant medical records and served as the true head circumference value (i.e., gold standard) for analysis. We calculated the proportion of head circumference measurements in agreement between the BC and BDMP data. We assigned growth chart head circumference percentile categories to each BC and BDMP measurement, and calculated the sensitivity and specificity of BC-based categories to predict BDMP-based categories.

RESULTS

No difference was found in head circumference measurements between the two sources in 77.9% (n = 1,727) of study infants. The sensitivity of BC-based head circumference percentile categories ranged from 85.6% (<3rd percentile) to 92.7% (≥90th percentile) and the specificity ranged from 97.6% (≥90th percentile) to 99.3% (<3rd percentile).

CONCLUSIONS

BC head circumference measurements agreed with those abstracted from the medical chart the majority of the time. Head circumference measurements on the BC were more specific than sensitive across all standardized growth chart percentile categories.

Predictors of prenatal smoking and attempted smoking cessation during pregnancy: a community-based study of Romani women in Southeastern Europe

Background

The objective of this study was to examine predictors of prenatal smoking, and attempted smoking cessation during pregnancy among Romani women.

Methods

A community-based, cross-sectional study (November 2012 to February 2013) of 410 Romani women in Roma settlements in Serbia and Macedonia was conducted. Logistic regression was used to identify predictors of prenatal smoking and attempted smoking cessation during pregnancy.

Results

Romani women older than 30 years and those who were living with a man were over twice as likely (adjusted odds ratio (aOR) 2.48, 95% confidence interval (CI) 1.12-5.46; aOR 2.09, 95% CI 1.27-3.43) to smoke during pregnancy, compared to women <20 and married women, respectively. An inverse relationship between education and prenatal smoking was observed (for primary education versus no education, aOR 0.56, 95% CI 0.32-0.98; for secondary or higher education versus no education, aOR 0.38, 95% CI 0.16-0.90). Having a husband/partner who smokes was associated with significantly increased likelihood of prenatal smoking (aOR 3.71, 95% CI 2.20-6.25) and decreased likelihood of attempting to quit (aOR 0.51, 95% CI 0.24-1.06).

Conclusions

Culturally sensitive and comprehensive prevention strategies and intervention programs are needed to reduce smoking during pregnancy among Romani women, including interventions targeting male partners.

Maternal Smoking during Pregnancy and Necrotizing Enterocolitis-associated Infant Mortality in Preterm Babies

Few studies have examined the possible pregnancy-related risk factors for necrotizing enterocolitis (NEC)-associated deaths during infancy. Infant death due to NEC in preterm babies was identified from the US Linked Livebirth and Infant Death records between 2000 and 2004. The average number of cigarettes per day reported by the mothers who were smoking during pregnancy was classified in three categories: non-smoking, light smoking (<10 cigarettes/day) and heavy smoking (≥10 cigarettes/day). Logistic regression analyses examined the association between prenatal smoking and NEC-associated infant mortality rates with adjustment for potential confounders. Compared with non-smoking mothers, light and heavy smoking mothers have a higher risk of NEC-associated infant mortality [light smoking: adjusted odds ratio (aOR) = 1.21, 95% confidence interval (CI), 1.03-1.43; heavy smoking: aOR = 1.30, 95% CI, 1.12-1.52], respectively. Moreover, the association was stronger among white race (light smoking: aOR = 1.69, 95% CI, 1.34-2.13; heavy smoking: aOR = 1.44, 95% CI, 1.18-1.75) and female babies (light smoking: aOR = 1.31, 95% CI, 1.02-1.69; heavy smoking: aOR = 1.62, 95% CI, 1.29-2.02). Maternal smoking during pregnancy is associated with increased risks of infant mortality due to NEC in preterm babies, especially in white race and female babies.