A systematic review of evidence for maternal preconception exposure to outdoor air pollution on Children's health.

The preconception period is a critical window for gametogenesis, therefore preconception exposure to air pollutants may have long-term effects on children. We systematically reviewed epidemiological evidence concerning the effects of preconception ambient air pollution exposure on children's health outcomes and identified research gaps for future investigations. We searched PubMed and Web of Science from journal inception up to October 2022 based on an established protocol (PROSPERO: CRD42022277608). We then identified 162 articles based on searching strategy, 22 of which met the inclusion criteria. Studies covered a wide range of health outcomes including birth defects, preterm birth, birthweight, respiratory outcomes, and developmental outcomes. Findings suggested that exposure to outdoor air pollutants during maternal preconception period were associated with various health outcomes, of which birth defects has the most consistent findings. A meta-analysis revealed that during 3-month preconception period, a 10 µg/m3 increase in PM10 and PM2.5 was associated with relative risk (RR) of birth defects of 1.06 (95% confidence interval (CI): 1.00, 1.02) and 1.14 (95% CI: 0.82, 1.59), respectively. Preterm birth, low birthweight, and autism have also been associated with maternal preconception exposure to PM2.5, PM10, O3 and SO2. However, the significance of associations and effect sizes varied substantially across studies, partly due to the heterogeneity in exposure and outcome assessments. Future studies should use more accurate exposure assessment methods to obtain individual-level exposures with high temporal resolution. This will allow the exploration of which specific time window (weeks or months) during the preconception period has the strongest effect. In future epidemiologic studies, integrating pathophysiologic biomarkers relevant to clinical outcomes may help improve the causal inference of associations between preconception exposure and health outcomes suggested by the current limited literature. Additionally, potential effects of paternal preconception exposure need to be studied.

Maternal preconception occupational exposure to cleaning products and disinfectants and offspring asthma.

BACKGROUND: Emerging research suggests health effects in offspring after parental chemical exposures before conception. Many future mothers are exposed to potent chemicals at work, but potential offspring health effects are hardly investigated. OBJECTIVE: We sought to investigate childhood asthma in relation to mother's occupational exposure to cleaning products and disinfectants before conception. METHODS: The multicenter Respiratory Health In Northern Europe/Respiratory Health In Northern Europe, Spain and Australia generation study investigated asthma and wheeze starting at age less than 10 years in 3318 mother-offspring pairs. From an asthma-specific Job-Exposure Matrix and mothers' occupational history, we defined maternal occupational exposure to indoor cleaning agents (cleaning products/detergents and disinfectants) starting before conception, in the 2-year period around conception and pregnancy, or after birth. Never-employed mothers were excluded. Exposed groups include cleaners, health care workers, cooks, and so forth. Associations were analyzed using mixed-effects logistic regression and ordinary logistic regression with clustered robust SEs and adjustment for maternal education. RESULTS: Maternal occupational exposure to indoor cleaning starting preconception and continuing (n = 610) was associated with offspring's childhood asthma: odds ratio 1.56 (95% CI, 1.05-2.31), childhood asthma with nasal allergies: 1.77 (1.13-2.77), and childhood wheeze and/or asthma: 1.71 (95% CI, 1.19-2.44). Exposure starting around conception and pregnancy (n = 77) was associated with increased childhood wheeze and/or asthma: 2.25 (95% CI, 1.03-4.91). Exposure starting after birth was not associated with asthma outcomes (1.13 [95% CI, 0.71-1.80], 1.15 [95% CI, 0.67-1.97], 1.08 [95% CI, 0.69-1.67]). CONCLUSIONS: Mother's occupational exposure to indoor cleaning agents starting before conception, or around conception and pregnancy, was associated with more childhood asthma and wheeze in offspring. Considering potential implications for vast numbers of women in childbearing age using cleaning agents, and their children, further research is imperative.

Maternal preconception and first trimester exposure to PM10 and the risk of oral clefts in offspring: a population-based, case-control study.

BACKGROUND: Current literature describes limited and controversial evidence on the associations between maternal preconception and first trimester exposure to particulate matter with a diameter ≤10 µm (PM10) and the risk of oral cleft (OC). METHODS: We conducted a case-control study involving 3086 OC cases and 7950 controls, registered in the Maternal and Child Health Certificate Registry in Liaoning Province between 2010 and 2015. PM10 concentrations were obtained from the Environment Protection Bureau. The exposure windows included the 3 months before pregnancy, the first trimester and the individual months. Unconditional logistic regression model was performed to estimate the OR and 95% CI for the association between PM10 exposure and the risk of OC, cleft lip only (CLO), cleft palate only (CPO), and cleft lip and palate (CLP). RESULTS: Maternal PM10 exposure was positively associated with an increased risk for OC during the 3 months preconception (per 10 µg/m3 increment: OR=1.04, 95% CI 1.01 to 1.07; highest vs lowest quartile: OR=1.23, 95% CI 1.04 to 1.45) and the first trimester (per 10 µg/m3 increment: OR=1.05, 95% CI 1.02 to 1.08; highest vs lowest quartile: OR=1.37, 95% CI 1.15 to 1.64). Analyses based on individual months presented similar positive associations, particularly in the second month of pregnancy (OR=1.77, 95% CI 1.51 to 2.09) for highest versus lowest quartile. In the subtype analysis, stronger associations were observed for CLO, whereas there was negligible evidence for CPO and CLP. Sensitivity analyses using propensity score matching generated similar findings. CONCLUSIONS: Our study provides evidence that PM10 exposure during the 3 months preconception and the first trimester increases the risk of OC.

Air Pollution and the Risk of Birth Defects in Anqing City, China.

OBJECTIVE: This study aimed to explore evidence for the influence of air pollution on the risk of birth defects in China and contribute to establish prevention strategies. METHODS: We conducted a retrospective cohort study in Anqing city, Eastern China, from 2010 to 2012. Binary logistic regression models were used to estimate odds ratios (ORs) per 10 µg/m3 change for SO2, NO2, and PM10. RESULTS: For continuous exposure to SO2 (10 µg/m increase), the adjusted OR for birth defects is 1.20 [95% confidence interval (95% CI) 1.09 to 1.29] in the preconception. A 10 µg/m increase in SO2 (adjusted OR 1.26, 95% CI 1.15 to 1.36) during the second trimester is strongly associated with birth defects. No associations have been observed for NO2 and PM10. CONCLUSION: The results suggested that exposure to ambient SO2 during pregnancy may increase the risk of birth defects.

Investigating paternal preconception risk factors for adverse pregnancy outcomes in a population of internet users.

BACKGROUND: Paternal preconception risk factors such as smoking, exposure to environmental substances, medication use, overweight and advanced age correlate with the occurrence of malformations and birth defects in the offspring. Nonetheless, the prevalence of risk factors for adverse pregnancy outcomes in the male population has been scarcely investigated and no report on preconception interventions targeting prospective fathers is available. We conducted a web-based survey to measure the prevalence of paternal preconception risk factors for adverse pregnancy outcomes in an Italian population of Internet users. METHODS: Prospective or expectant fathers were enrolled during a four-week period through two of the main Italian web-sites dedicated to preconception, pregnancy, childhood and family care. Participants filled in a web questionnaire regarding preconception risk factors for adverse pregnancy outcomes. Logistic regression analysis was used to explore the predictors of paternal preconception risk factors. RESULTS: We enrolled 131 prospective and 205 expectant fathers. More than half of the total participants used medications during the preconception period, 35% were smokers and 8% were obese. Exposure to environmental substances was declared by almost 20% of the participants, with the group including pesticides/herbicides/professional paints being the most prevalent. More than a half of the study sample included men aged over 35 years. According to the multivariate analysis, smoking and exposure to environmental toxics were less frequent among individuals with a university degree (respectively: OR = 0.52; 95% CI 0.32-0.84; OR = 0.52; 95% CI 0.29-0.93). Paternal obesity and medication use in the preconception period were not associated with any of the independent variables. CONCLUSIONS: The prevalence of preconception risk factors among male population should not be neglected when planning preconception interventions, confirming that preconception health must be focused on the couple, rather than on women only.

No excess risks in offspring with paternal preconception exposure to disease-modifying antirheumatic drugs.

OBJECTIVE: To examine pregnancy outcomes in the partners of male patients with inflammatory joint disease who were or were not exposed to disease-modifying antirheumatic drugs (DMARDs) before conception compared with the outcomes in reference subjects from the general population. METHODS: Linkage of data from a longitudinal observational study of patients with inflammatory joint disease (the Norwegian Disease-Modifying Antirheumatic Drug [NOR-DMARD] registry study) and the Medical Birth Registry of Norway (MBRN) enabled a comparison of pregnancy outcomes in the partners of men with inflammatory joint disease. Outcomes of pregnancies in which the father was exposed to DMARDs within 12 weeks of conception and those in which the father was never exposed to DMARDs were analyzed separately and compared with the outcomes in reference subjects. Potential associations between DMARD exposure and adverse pregnancy outcomes were assessed by logistic regression analysis. RESULTS: A total of 1,796 men with inflammatory joint disease were associated with 2,777 births in the MBRN. In 110 of these births, the father had been exposed to DMARDs within 12 weeks before conception, and in 230 births the father had never been exposed to DMARDs before conception. The DMARDs (monotherapy or combination treatment) to which the fathers were exposed most frequently within 12 weeks of conception were methotrexate (n = 49), sulfasalazine (n = 17), and tumor necrosis factor inhibitors (n = 57). Neither adverse pregnancy outcomes nor occurrence of congenital malformations differed between patients and reference subjects in either group. CONCLUSION: Preconception paternal exposure to DMARDs was not associated with an increase in adverse pregnancy outcomes. Importantly, no increased risk of congenital malformations was observed.

[SYNERGISM OF PRECONCEPTIVE RADIATION EXPOSURE AND PARENTS' ONCO-PATHOLOGY IN THE RISE OF CARCINOGENIC RISK IN THE OFFSPRINGS OF PROFESSIONAL EMPLOYEES].

The problem of carcinogenic risk in offsprings of individuals exposed to radiation is challenging and insufficiently studied. In that there are no evaluations of the interaction between radiation and non-radiation factors. The aim of the study was the analysis of interaction of preconceptive radiation exposure and parents' onco-pathology in cancer mortality in offsprings (F1) of workers (fathers) of the Mayak Production Association exposed to a wide range of doses of radiation over a year prior conception. The number of offspring is 8191 individuals (4180 men and 4011 women). The analysis was performed with the use of fourfold table and eightfold tables. The interaction offactors was estimated on the base of the additive and multiplicative models. The studied factors were independent. The odds ratio (OR) of cancer mortality in the offspring with parents' oncopathology (1.43) was insignificant. OR of cancer mortality in preconceptive radiation exposure in a dose over 110 mGy and without parents' onco-pathology was 2.61 (1.52-4.49), and in their combination--3.86 (1.93-7.71). Index of synergism of preconceptive radiation exposure and parents' onco-patholog in the rise of carcinogenic risk in the offspring was 1.34 and the character of their interaction was multiplicative. Thus, for the first time there was established the interaction between radiation and non-radiation factors in the synergism sort in the increase of carcinogenic risk in the offspring of people exposed to radiation.