Maternal tobacco exposure and health-related quality of life during pregnancy: a national-based study of pregnant women in China

Association between gestational cardiovascular health in the first trimester and pregnancy outcomes in the China birth cohort

OBJECTIVES

To determine whether gestational cardiovascular health (CVH) during the first trimester is associated with a risk of adverse pregnancy outcomes.

STUDY DESIGN

A multicentre prospective cohort; part of the China birth cohort study.

METHODS

Pregnant women were recruited at 6-13+6 gestation weeks and followed to delivery to identify pregnancy outcomes. Gestational CVH in the first trimester was assessed using five CVH metrics: body mass index, smoking, blood pressure, glucose, and lipids. Multilevel modified Poisson regression models calculated the relative risks (RRs) and 95% confidence intervals (95% CIs) of gestational CVH for adverse pregnancy outcomes.

RESULTS

Among 56,852 pregnant women, the mean score for gestational CVH during the first trimester was 9.1. Adjusting for confounding factors, each 1-point decrease in the total gestational CVH score significantly increased the risk of hypertensive disorders of pregnancy (RR = 1.682, 95% CI: 1.624-1.743), gestational diabetes mellitus (RR = 1.405, 95% CI: 1.384-1.426), preterm birth (RR = 1.184, 95% CI: 1.174-1.195), large for gestational age (RR = 1.224, 95% CI: 1.199-1.250), caesarean delivery (RR = 1.073, 95% CI: 1.049-1.097), and low Apgar score (RR = 1.131, 95% CI: 1.003-1.277) significantly increased. Meanwhile, the risk of small for gestational age decreased (SGA; RR = 0.922, 95% CI: 0.898-0.946). Worsened CVH categories significantly increased the risk of adverse pregnancy outcomes, excluding SGA.

CONCLUSIONS

Poor gestational CVH in the first trimester significantly increases the risk of adverse pregnancy outcomes, emphasising the need for early improvement in gestational CVH.

A meta-analysis of the effects of vitamin C supplementation for pregnant smokers on the pulmonary function of their offspring

BACKGROUND

At present, the need for vitamin C supplementation for pregnant smokers has not been fully studied. This study is aimed at investigating whether vitamin C supplementation for pregnant smoking women can improve the pulmonary function of their offspring.

METHODS

Four databases were searched from inception to April 1, 2023 for studies on the effect of vitamin C supplementation to pregnant smokers on the pulmonary function of their offspring. Meanwhile, the reference lists of relevant studies were manually searched. The risk of bias in the included studies was assessed using the Cochrane Collaboration tool, and the data was analyzed using STATA/SE 17.0.

RESULTS

Four randomized controlled trials (RCTs), all of high quality, were enrolled in this meta-analysis, including 787 pregnant women. The offspring of pregnant smokers who received vitamin C supplementation exhibited improved Forced Expiratory Flow between 25 and 75% (FEF25-75), FEF50, FEF75, and Forced Vital Capacity (FVC) compared to those who did not receive vitamin C supplementation. However, there was no statistically significant difference in Forced Expiratory Volume at 0.5 s (FEV0.5) and the ratio of FEV0.5 to FVC between the offspring of pregnant smokers who received vitamin C and the control group.

CONCLUSION

Vitamin C supplementation for smoking pregnant women may enhance the pulmonary function of their offspring, particularly in FEF25-75, FEF50, FEF75, and FVC. Nevertheless, there are no significant differences in FEV0.5 and the FEV0.5/FVC ratio. These findings suggest that vitamin C supplementation has potential benefits for specific pulmonary function. Further studies are needed to comprehensively assess the effects of vitamin C on pulmonary function in the context of maternal smoking during pregnancy.

Prenatal exposure to fine particulate matter chemical constituents and the risk of stillbirth and the mediating role of pregnancy complications: A cohort study

Evidence on the association of fine particulate matter (PM2.5) exposure with stillbirth is limited and inconsistent, which is largely attributed to differences in PM2.5 constituents. Studies have found that the hazards of certain PM2.5 constituents to the fetus are comparable to or even higher than total PM2.5 mass. However, few studies have linked PM2.5 constituents to stillbirth. Moreover, the mediating role of pregnancy complications in PM2.5-related stillbirth remains unclear. To our knowledge, this study was the first to explore the individual and mixed associations of PM2.5 and its constituents with stillbirth in China. After matching the concentrations of PM2.5 and its constituents (sulfate [SO42-], nitrate [NO3-], ammonium [NH4+], organic matter [OM], and black carbon [BC]) for participants according to their geographical location, there were 170,507 participants included in this study. We found that stillbirth was associated with exposure to PM2.5 and its constituents in the year before pregnancy and during the entire pregnancy, and the associations in trimester 1 were strongest. The risk of stillbirth increased sharply when PM2.5 and its constituents during pregnancy exceeded the median concentrations. Moreover, stillbirth was associated with exposure to the mixtures of SO42-, NO3-, NH4+, OM, and BC before and during pregnancy (trimesters 1 and 2). Meanwhile, two-pollutant models also suggested stillbirth was associated with PM2.5 and its constituents in the year before and during pregnancy. The associations of PM2.5 and its constituents with stillbirth were stronger in mothers with advanced age and without cesarean delivery history. Additionally, hypertensive disorders in pregnancy, gestational diabetes, and placental abruption mediated the association of PM2.5 with stillbirth. Therefore, enhanced protection against PM2.5 for pregnant women before and during pregnancy and targeted interventions for pregnancy complications and anthropogenic sources of PM2.5 constituents are important to reduce stillbirth risk.

Physical Activity and Self-Perception of Mental and Physical Quality of Life during Pregnancy: A Systematic Review and Meta-Analysis

Self-perception of health status (quality of life) is considered one of the best indicators of health and well-being. However, during pregnancy, it could be impacted not only by physiological and anatomical changes, but by poor lifestyle habits like high sedentary behaviour or bad nutrition. This study assesses the effects of physical activity RCT interventions during pregnancy on both mental and physical components of quality of life. A systematic review and two meta-analyses were performed (PROSPERO registration number: CRD42022370467). Of the 207 articles captured both in English and Spanish, seven articles were deemed eligible for inclusion. The two analyses performed found that physically active pregnant women had better scores of mental self-perception of quality of life (z = 2.08, p = 0.04; SMD = 0.34, 95% CI = 0.02, 0.67, I2 = 76%, Pheterogeneity = 0.0004) and in physical self-perceived health status (z = 2.19, p = 0.03; SMD = 0.33, 95% CI = 0.03, 0.63, I2 = 71%, Pheterogeneity = 0.002) compared to control group pregnant women. Physical activity interventions could potentially increase mental and physical self-perception of quality of life during pregnancy.

Secondhand and thirdhand smoke: a review on chemical contents, exposure routes, and protective strategies

Secondhand smoke (SHS: a mixture of sidestream and mainstream smoke) and thirdhand smoke (THS: made up of the pollutants that settle indoors after smoking in closed environments) are a significant public health concern. SHS and THS contain various chemicals which can be released into the air or settle on surfaces. At present, the hazards of SHS and THS are not as well documented. In this review, we describe the chemical contents of THS and SHS, exposure routes, vulnerable groups, health effects, and protective strategies. The literature search was conducted for published papers on September 2022 in Scopus, Web of Science, PubMed, and Google Scholar databases. This review could provide a comprehensive understanding of the chemical contents of THS and SHS, exposure routes, vulnerable groups, health effects, protective strategies, and future researches on environmental tobacco smoke.

Elevated concentrations of chromium in maternal serum, umbilical cord serum, and cord tissue are associated with an increased risk for orofacial clefts

Chromium (Cr) exposure during gestation causes malformations in animal experiments. In this multicenter case-control study, we initially involved 130 orofacial clefts (OFCs) and 260 controls to assess the association between Cr concentration and risk for OFCs. Then, umbilical cord serum (49 vs. 119) and cord tissue (84 vs. 142) were used to validate the association between Cr and OFCs. We found that maternal serum Cr concentrations in OFC cases were significantly higher than those in controls. Compared with the lowest tertile of maternal serum Cr concentration, the highest tertile of Cr increased the risk for OFCs [OR = 2.14 (1.14-4.05)]. In the validation cohort of umbilical cord serum and tissue, higher concentrations of Cr were associated with increased risks for OFCs in a dose-dependent manner (all Ps for trends <0.05). Cr concentrations in maternal serum and cord serum showed a positive correlation. The Cr concentration in cord serum was inversely correlated with egg and milk consumption frequencies, and the Cr concentration in cord tissue was positively associated with indoor coal burning. In conclusion, prenatal Cr exposure is a risk factor for OFCs, and indoor coal burning during pregnancy may be one of the sources of Cr exposure.

Association between secondhand smoke exposure in pregnant women and their socioeconomic status and its interaction with age: a cross-sectional study

Background

Existing evidence highlights that exposure to secondhand smoke (SHS) is a risk factor for pregnant women’s health and is possibly affected by individual characteristics. This study aimed to explore the effect of individual socioeconomic status (SES) on SHS exposure among pregnant women in the third trimester and the interaction effect of age.

Methods

A total of 678 nonsmoking pregnant women with a median age of 29.0 years from 14 communities in a medium-sized city were recruited for this survey. Exposure to SHS was defined as the self-reported smoking habit of a spouse/partner. Individual SES characteristics consisted of marital status, educational attainment, employment and per capita monthly income.

Results

There were 238 (35.1%) participants who suffered from SHS exposure. Compared to the pregnant women who were employed, those who were unemployed were more likely to suffer from SHS exposure (OR = 1.572, 95% CI: 1.013–2.441). Participants who had a high school or technical secondary school education were more likely to be exposed to SHS than those with a college education or above (OR = 1.601, 95% CI: 1.029–2.449). Advanced age was a protective factor for participants with a college education or above (OR = 0.939, 95% CI: 0.884–0.997), but age increased the risk of SHS exposure among women who had unstable marriages (OR = 1.256, 95% CI: 1.019–1.549).

Conclusion

Exposure to SHS was very common among pregnant women in the third trimester. Pregnant women with a low SES and an older age should be considered a key population for the implementation of public health interventions.

Prenatal Exposure to PM2.5 and Its Specific Components and Risk of Hypertensive Disorders in Pregnancy: A Nationwide Cohort Study in China

Hypertensive disorders in pregnancy (HDP) are a leading cause of maternal mortality and adverse birth outcomes. Fine particulate matter (PM_2.5) has been linked to HDP risk; however, limited studies have explored the relationships between specific chemical constituents of PM_2.5 and HDP risk. Based on maternal data from the China Labor and Delivery Survey (CLDS), this study included a total of 67,659 participants from 95 participant hospitals in 25 provinces of China between March 1, 2015, and December 31, 2016. Maternal exposure to total PM_2.5 mass and six main components during pregestation and pregnancy were estimated using the Combined Geoscience-Statistical Method. Multilevel logistic regression models were applied to quantify the associations, controlling for sociodemographic characteristics. We found that an interquartile range (IQR) increase in PM_2.5 exposure during the second trimester was associated with a 14% increase in HDP risk (95% CI: 2%, 29%). We observed that black carbon (BC) and SO₄^2- had larger or comparable estimates of the effect than total PM_2.5 mass. The association estimates were greater in the gestational hypertension group than in the group of pre-eclampsia and eclampsia. Our findings suggest that PM_2.5 exposure and specific chemical components (particularly BC and SO₄^2-) were associated with an increased HDP risk in China.