Pulmonary hypertension (PH) is a fatal disease caused by progressive pulmonary vascular remodeling (PVR). Currently, the mechanisms underlying the occurrence and progression of PVR remain unclear, and effective therapeutic approaches to reverse PVR and PH are lacking. Since the beginning of the 21st century, the endogenous sulfur dioxide (SO2)/aspartate transaminase system has emerged as a novel research focus in the fields of PH and PVR. As a gaseous signaling molecule, SO2 metabolism is tightly regulated in the pulmonary vasculature and is associated with the development of PH as it is involved in the regulation of pathological and physiological activities, such as pulmonary vascular cellular inflammation, proliferation and collagen metabolism, to exert a protective effect against PH. In this review, we present an overview of the studies conducted to date that have provided a theoretical basis for the development of SO2-related drug to inhibit or reverse PVR and effectively treat PH-related diseases.

BackgroundIt is projected that the frequency, density, and duration of compound hot extreme may increase in the 21st century in the context of global warming.ObjectiveTo explore the association between compound hot extreme and blood pressure, and identify sensitive populations.MethodsThis was a cross-sectional study. The study subjects were from six Guangdong Province Chronic Disease and Nutrition Surveys during 2002 through 2015. A questionnaire was administered to the participants with questions about demographic information, drinking and smoking status, and measurements on their height, weight, and blood pressure were also collected. We chose the data of May, September, and October to explore the association between compound hot extreme and blood pressure. Compound hot extreme means a hot day with a proceeding hot night. Daily meteorological data were obtained from China Meteorological Data Service Centre. We employed inverse distance weighting to interpolate the temperature and relative humidity values for each participant. A distributed lag non-linear model was used to estimate the association between compound hot extreme and blood pressure. Stratified analyses by sex, age, area, body mass index (BMI), smoking status, and drinking status were also performed to identify sensitive populations. A sensitivity analysis was conducted by adjusting the degrees of freedom for lag spline and removing relative humidity.ResultA total of 10967 participants without history of hypertension were included in this study. The average systolic blood pressure (SBP) was 120.8 mmHg and the average diastolic blood pressure (DBP) was 74.5 mmHg. The proportion of participants who experienced hot day, hot night, or compound hot extreme were 9.34%, 17.95% and 2.90%, respectively. Compared to hot day, hot night and compound hot extreme were related with decreased blood pressure, and the effect of compound hot extreme was stronger: the changes and 95%CI for SBP was −6.2 (−10.3-−2.1) mmHg, and for DBP was −2.7 (−5.2-−0.2) mmHg. Compound hot extreme induced decreased SBP among male, population ≥ 65 years, and those whose BMI < 24 kg·m-2, and their ORs (95%CIs) were −6.2 (−10.7-−1.6). −19.1 (−33.0-−5.1), and −6.7 (−11.8~−1.6) mmHg, respectively, and also decreased DBP among population ≥ 65 years, and its OR (95%CI) was −8.4 (−15.6-−1.1) mmHg. During compound hot extremes, participants living in rural areas showed decreased SBP and DBP, and the ORs (95%CIs) were −10.5 (−16.6-−4.5) and −4.4 (−7.7-−1.1) mmHg respectively, while those living in urban areas showed increased SBP, and the OR (95%CI) was 9.7 (2.9-16.5) mmHg. A significant decrease in blood pressure [OR (95%CI)] was also found in non-smokers [DBP, −3.7 (−6.6-−0.8) mmHg] and non-drinkers [SBP, −4.8 (−9.4-−0.2) mmHg; DBP, −3.4 (−6.0-−0.9) mmHg].ConclusionCompound hot extreme is negatively associated with SBP, and being male, aged 65 years and over, and having BMI < 24 kg·m−2 may be more sensitive to compound hot extreme.

Background Although studies have investigated the association between early-life exposure to fine particulate matter (PM2.5) and childhood asthma/wheezing, results are inconsistent and the susceptible exposure window remains largely unknown. Methods A prospective birth cohort study was conducted to recruit pregnant women during their early pregnancy, and to follow up them and their children up to 3-4 years old. Diagnosis of asthma/wheezing was extracted from children's medical records. A spatiotemporal land-use regression (ST-LUR) model was used to assess maternal exposure to PM2.5 during pregnancy and their children's exposure after birth. The Cox proportional hazards model and accelerated failure time model (for violation of proportional hazards assumption) were applied to estimate the effects of prenatal and postnatal exposures to PM2.5 on the risk of childhood asthma/wheezing. Results A total of 3725 children were included, and 392 children (10.52%) were diagnosed with asthma/wheezing. Both prenatal and postnatal exposures to PM2.5 were positively associated with the risk of asthma/wheezing. Each interquartile range (IQR) increment in PM2.5 exposure during the entire pregnancy (4.8 mu g/m(3)) and the period from birth to the end of follow-up (1.5 mu g/m(3)) was associated with adjusted hazard ratios (HRs) of 1.44 [95% confidence interval (CI): 1.13, 1.85] and 2.74 (95% CI: 2.59, 2.91), respectively. Subgroup analyses showed greater HRs for PM2.5 exposures during the pseudoglandular stage (6-16 gestational weeks [GWs]: IQR = 4.8 mu g/m(3), HR = 1.10, 95% CI: 1.02, 1.18) and canalicular stage (16-24 GWs: IQR = 4.8 mu g/m(3), HR = 1.13, 95% CI:1.03, 1.23) than other stages, and also showed significant effects in the first three-year period after birth (IQR = 1.5 mu g/m(3), HR = 2.37, 95% CI: =2.24, 2.51). Conclusion Higher prenatal and postnatal PM2.5 exposures may increase the risk of childhood asthma/wheezing. The pseudoglandular stage, canalicular stage, and the first three years after birth may be key susceptible to exposure windows.

ImportanceThe ongoing pandemic of COVID-19 is still affecting our life, but the effects of lockdown measures on gestational diabetes mellitus (GDM) in pregnant women remain unclear. AimTo investigate the association between COVID-19 lockdown and GDM. Subjects and MethodsMedical records of 140844 pregnant women during 2015-2020 were extracted from 5 hospitals in Guangdong Province, China. Pregnant women who underwent the COVID-19 Level I lockdown (1/23 - 2/24/2020) during pregnancy were defined as the exposed group (N=20472) and pregnant women who underwent the same calendar months during 2015-2019 (1/23 - 2/24) were defined as the unexposed group (N=120372). Subgroup analyses were used to explore the potential susceptible exposure window of COVID-19 lockdown on GDM. Cumulative exposure is quantitatively estimated by assigning different weights to response periods with different exposure intensities. A logistic regression model was used to estimate the association between COVID-19 lockdown exposure and GDM. ResultsThe rates of GDM in the exposed and unexposed groups were 15.2% and 12.4%, respectively. The overall analyses showed positive associations (odds ratio, OR=1.22, 95%CI: 1.17, 1.27) between lockdown exposure and GDM risk in all pregnant women. More pronounced associations were found in women who underwent the COVID-19 lockdown in their first four months of pregnancy, and the adjusted OR values ranged from 1.24 (95%CI: 1.10, 1.39) in women with 5-8 gestational weeks (GWs) to 1.35 (95%CI: 1.20, 1.52) with < 5 GWs. In addition, we found a positive exposure-response association of cumulative lockdown exposure with the risk of GDM. ConclusionsThe COVID-19 lockdown was associated with an increased risk of GDM, and the first four months of pregnancy may be the window for sensitive exposure.

Ozone (O-3) exposure may lead to the development and exacerbation of asthma or wheezing in postnatal children; however, it has rarely been studied before and during pregnancy. Wheezing is one of the most common symptoms when diagnosing of asthma; thus, we investigated the associations of O-3 exposure before and during pregnancy with wheezing in preschool children and the potential susceptible exposure windows from a heavily polluted city in China. This population-based birth cohort study, which included 3725 mother-child pairs from Guangzhou, began in 2016, and the follow-up period ended on July 31, 2020. We used a spatiotemporal land-use-regression model combined with activity patterns to estimate the daily O-3 exposure levels during the pre-pregnancy period and each trimester, and wheezing was recorded by reviewing medical records. We used the Cox proportional hazard model to quantify the effects of O-3 exposure on childhood wheezing adjusted for potential confounders. No significant association was detected between pre-pregnancy exposure to O-3 and child-hood wheezing. However, increased ambient O-3 exposures throughout pregnancy and in the second trimester were positively associated with the risk of childhood wheezing, with hazard ratios (HRs) and 95% confident intervals (CIs) per interquartile range (IQR) increment of 1.22 (95% CI: 1.04-1.44) and 1.31 (95% CI: 1.09-1.58), respectively. The effects of maternal O-3 exposure on childhood wheezing risk was stronger when the exposure occurred in the warm conception season (P < 0.05). Significant childhood wheezing risk could be attributable to maternal O-3 exposure, especially during the second trimester and with warm-season conception in Guangzhou. Further cohorts of children, particularly school age children who have more robust asthma diagnoses, should be investigated in the future.

BackgroundGlobal warming may increase the frequency of compound hot extreme (CHE).However, there is still a lack of studies assessing the associations between CHE and preterm birth (PTB), and the underlying biological mechanisms remain unclear.ObjectiveTo estimate the association of exposure to CHE during pregnancy with PTB, and to explore the roles of inflammatory, endothelial dysfunction, and oxidative stress in the association between CHE and PTB.MethodsAll participants were selected from the Prenatal Environments and Offspring Health (PEOH), a prospective birth cohort conducted in Guangzhou. In this study, a total of 2449 participants who gave birth from May to October in 2014 to 2017 were enrolled, and among them blood samples were collected from 311 preterm (n=43) and full-term (n=268) pregnant women at the time of delivery. A hot day/night was identified as a day when the daily maximum temperature/minimum temperature was higher than its 90th percentile in the study period, and a CHE was defined as having both a hot night and a following hot day. The meteorological data were obtained from the China Meteorological Data Sharing Service System. Anusplin was used to assess the daily maximum temperature, daily minimum temperature, and relative humidity of the participant residence. Enzyme-linked immunosorbent assay (ELISA) was used to measure C reactive protein (CRP), endothelin-1 (ET-1), and malondialdehyde (MDA) levels in maternal serum, and their results were transformed by natural logarithm. A distributed lag nonlinear model was used to investigate the associations of exposures to hot day, hot night, and CHE during pregnancy with PTB at different lag days, and a logistic regression model was used to investigate the associations of CRP, ET-1, and MDA with PTB.ResultsThe incidence rate of PTB was 6.2% in all selected participants. Compared with the non-hot day, the RRs (95%CIs) of CHE in lag 3, 7, and 14 days on PTB were 1.43 (1.12-1.84), 1.24 (1.08-1.43), and 1.17 (1.05-1.30), respectively, and the cumulative effects (% difference) (95%CI) of CHE in lag 14 days on maternal serum CRP, ET-1, and MDA were 0.33% (−0.45%-1.12%), 0.59% (0.11%-1.07%), and 0.57% (0.09%-1.05%), respectively. Compared with the Q1 (lowest quartile) for CRP, ET-1 and MDA, the RRs (95%CIs) of Q4 (highest quartile) for PTB were 1.27 (0.50-3.22), 1.51 (0.61-3.72), and 2.07(0.81-5.27), respectively.ConclusionMaternal exposure to CHE during pregnancy might be associated with an increased risk of PTB. Prenatal exposure to CHE is positively associated with maternal serum CRP, ET-1, and MDA, and the three biochemical indicators are also positively associated with PTB. However, the above conclusions still need further confirmation.

[背景]硒(Se)是人体必需的元素,但过量的硒会产生毒性.孕妇孕期硒暴露水平与胎儿发育的关系目前尚不明确.[目的]了解广州市孕妇孕期硒暴露与孕晚期胎儿头围的关系.[方法]所有孕妇均来自2016年起在广州进行的产前环境与后代健康(PEOH)队列.研究对象分别在孕早期(孕周≤13周)完成基线调查并建立随访档案,在孕晚期(孕周≥28周)进行随访.调查包括面对面采访的问卷调查并从医院信息系统中提取孕妇的产前护理记录,另分别收集孕早期和孕晚期孕妇各15.0mL尿液,孕晚期对胎儿进行超声检查,记录胎儿头围的生长发育情况.根据是否提供尿样及所有资料的完整性,孕早期和孕晚期分别剔除部分对象后,研究共纳入2 739名孕妇;其中孕早期和孕晚期各纳入孕妇2138、1383名,分别分析孕早、晚期孕妇硒暴露与孕晚期胎儿头围的关系.尿硒浓度(ωSe)通过尿肌酐校正(计量单位为:μg·g-1,以肌酐计,后同),并经自然对数转换为InωSe.调整孕妇年龄、受教育程度、家庭收入和孕前体重指数、孕次、孕周数、胎儿性别、二手烟暴露、钙片的摄入、肉与海鲜的摄入等因素后,应用多重线性回归模型估算孕妇硒暴露水平与胎儿头围之间的关系,并进一步分性别进行分析.[结果]在2739名孕妇中,年龄≥30岁的有1926人(70.3％),男胎有1474人(53.8％),受教育程度在高中及以上的有2313人(84.4％),怀孕期间有二手烟暴露的871人(31.8％),孕周≥37周的有2637人(96.3％).孕早期和孕晚期孕妇的硒暴露水平的中位数及第25、75百分位数分别为38.5(30.1,44.5)μg·g-1 和38.9(28.7,54.0)μg·g-1.孕晚期胎儿头围为(218.1±41.4)mm.经多重线性回归模型分析,未观察到孕早期的硒暴露与孕晚期胎儿头围的关联有统计学意义.但孕晚期孕妇尿InωSe每增加一个单位,胎儿头围减小值及其95％可信区间(CI)为7.04(3.41～10.67)mm(P＜0.001).在孕晚期,孕妇硒暴露根据InωSe的四分位数分为四组(Q1～Q4),与Q1组相比,Q4组者胎儿的头围减小19.47(12.50～26.43)mm(P＜0.001).孕晚期孕妇尿中InωSe每增加一个单位,男胎和女胎的头围分别减小5.06(0.48～9.63)mm(P=0.031)、11.30(5.32～17.27)mm(P＜0.001),且男女差异为6.24(1.69～10.79)mm;与硒暴露Q1组相比,Q4组者男胎和女胎的头围分别减小18.13(8.45～27.81)mm、21.26(11.23～31.30)mm(均P＜0.001).[结论]在本人群的暴露水平下,孕晚期孕妇较高尿硒水平与孕晚期胎儿头围减小有关.

Background: Previous studies have demonstrated the embryotoxicity and fetotoxicity of thallium (Tl). However, the effects of prenatal exposure to Tl on birth weight and placental weight and the mediating role of placental weight in the association of Tl with birth weight remain unclear. Methods: We recruited 2,748 participants from the ongoing Prenatal Environment and Offspring Health Cohort (PEOH Cohort) study, which was initiated in 2016 in Guangzhou, China. The Tl concentrations in maternal urine samples collected during the first and third trimester were determined by inductively coupled plasma mass spectrometry. Birth weight and placental weight were extracted from maternal medical records. Results: Pregnant women exposed to the highest tertile of Tl in the first trimester (β = −42.7 g, 95% CI: −82.3, −3.1 g) and third trimester (β = −50.6 g, 95% CI: −99.0, −2.3 g) had babies with lower birth weights than those exposed to the lowest tertile. We also found significant negative associations of exposure to Tl concentrations in the first and third trimester with placental weight. Mediation analyses showed that 50.3% (95% CI: 15.9, 79.2%) and 33.5% (95% CI: 1.3, 80.3%) of the effects of Tl exposure in the first and third trimester on birth weight were mediated by decreased placental weight. Conclusion: Our results suggest that prenatal exposure to Tl is negatively associated with birth weight and that this association may be mediated by decreased placental weight.

Abstract Background The effects of COVID-19 lockdown measures on maternal and fetal health remain unclear. We examined the associations of COVID-19 lockdown with gestational length and preterm birth (PTB) in a Chinese population. Methods We obtained medical records of 595,396 singleton live infants born between 2015 and 2020 in 5 cities in Guangdong Province, South China. The exposed group (N = 101,900) included women who experienced the COVID-19 Level I lockdown (1/23–2/24/2020) during pregnancy, while the unexposed group (N = 493,496) included women who were pregnant during the same calendar months in 2015–2019. Cumulative exposure was calculated based on days exposed to different levels of emergency responses with different weighting. Generalized linear regression models were applied to estimate the associations of lockdown exposure with gestational length and risk of PTB (< 37 weeks). Results The exposed group had a shorter mean gestational length than the unexposed group (38.66 vs 38.74 weeks: adjusted β = − 0.06 week [95%CI, − 0.07, − 0.05 week]). The exposed group also had a higher risk of PTB (5.7% vs 5.3%; adjusted OR = 1.08 [95%CI, 1.05, 1.11]). These associations seemed to be stronger when exposure occurred before or during the 23rd gestational week (GW) than during or after the 24th GW. Similarly, higher cumulative lockdown exposure was associated with a shorter gestational length and a higher risk of PTB. Conclusions The COVID-19 lockdown measures were associated with a slightly shorter gestational length and a moderately higher risk of PTB. Early and middle pregnancy periods may be a more susceptible exposure window.

Background: The ongoing COVID-19 pandemic has brought significant challenges to health system and consumed a lot of health resources. However, evidence on the hospitalization costs and their associated factors in COVID-19 cases is scarce. Objectives: To describe the total and components of hospitalization costs of COVID-19 cases, and investigate the associated factors of costs. Methods: We included 876 confirmed COVID-19 cases admitted to 33 designated hospitals from January 15th to April 27th, 2020 in Guangdong, China, and collected their demographic and clinical information. A multiple linear regression model was performed to estimate the associations of hospitalization costs with potential associated factors. Results: The median of total hospitalization costs of COVID-19 cases was $2,869.4 (IQR: $3,916.8). We found higher total costs in male (% difference: 29.7, 95% CI: 15.5, 45.6) than in female cases, in older cases than in younger ones, in severe cases (% difference: 344.8, 95% CI: 222.5, 513.6) than in mild ones, in cases with clinical aggravation than those without, in cases with clinical symptoms (% difference: 47.7, 95% CI: 26.2, 72.9) than those without, and in cases with comorbidities (% difference: 21.1%, 21.1, 95% CI: 4.4, 40.6) than those without. We also found lower non-pharmacologic therapy costs in cases treated with traditional Chinese medicine (TCM) therapy (% difference: -47.4, 95% CI: -64.5 to -22.0) than cases without. Conclusion: The hospitalization costs of COVID-19 cases in Guangdong were comparable to the national level. Factors associated with higher hospitalization costs included sex, older age, clinical severity and aggravation, clinical symptoms and comorbidities at admission. TCM therapy was found to be associated with lower costs for some non-pharmacologic therapies.

Although previous studies have proposed an association between maternal exposure to fine particulate matter (PM2.5) and the risk of gestational diabetes mellitus (GDM), such evidence remains rare. Additionally, the effects of PM2.5 on glycemic control in GDM patients are poorly known. In this study, we conducted a prospective birth cohort study in China, and aimed to investigate the association between maternal exposure to PM2.5 and the risk of GDM, identify the susceptible exposure window, and quantify the exposure-response relationships between PM2.5 and fasting glucose in GDM patients. A spatiotemporal land-use-regression model was used to estimate individual weekly PM2.5 exposure during pregnancy. A distributed lag nonlinear model incorporated with a Cox proportional hazard model was used to estimate the association between maternal exposure to PM2.5 and the risk of GDM. Among the 4174 pregnant women in our study, 1018 (24.4%) were diagnosed with GDM. Each 10 μg m−3 increment in PM2.5 exposures during the 24th gestational week was significantly associated with a higher risk of GDM [hazard ratio (HR) = 1.03, 95% CI (confidence interval): 1.01, 1.06]. Compared to the lowest quartile (Q1) of PM2.5 exposure, participants with the highest quartile (Q4) during the 21st–24th gestational weeks had a higher risk of GDM, and the strongest association was observed in the 22nd gestational week (HR = 1.15, 95%Cl: 1.02, 1.28). The mean PM2.5 exposures during the 21st–24th weeks were positively associated with fasting plasma glucose in pregnant women with GDM. Each 10 μg m−3 increase in the mean PM2.5 exposure was associated with a 0.07 mmol l−1 (95% CI: 0.04, 0.11 mmol l−1) increase in the fasting glucose level. Our findings suggest that maternal exposure to higher PM2.5 during pregnancy may increase the risk of GDM, and result in poor glycemic control among pregnant women with GDM. The 21st–24th gestational week period might be the (most)? susceptible exposure window of PM2.5.

Background: Strict lockdown measurements implemented during the COVID-19 pandemic have dramatically reduced the anthropogenic-based emissions in China. We aimed to comprehensively describe air pollution during and after the COVID-19 lockdown in China, and to estimate the mortality burden related to the air pollution changes. Methods: We analyzed national air quality monitoring and mortality data to describe the changes of air pollutants, and to estimate the health impact from air pollution changes during and after the lockdown periods in 2020 compared with 2018-2019. Changes in number of deaths and years of life lost (YLL) were used as indicators in the estimations. Findings: The mean air quality index (AQI), PM10, PM2·5, NO2, SO2 and CO concentrations during the lockdown period in 2020 across China declined by 18·2 (21·2%), 27·0μg/m3 (28·9%), 10.5μg/m3 (18·3%), 8·4μg/m3 (44·2%), 13·1μg/m3 (38·8%), and 0·3mg/m3 (27·3%) respectively, when compared to the same periods during 2018-2019 . We observed an increase in O3 concentration during the lockdown by 5·5μg/m3 (10·4%), and a slight decrease after the lockdown by 3·4μg/m3 (4·4%). As a result, there were 51·3 (95%CI: 32·2, 70·1) thousand fewer premature deaths (16·2 thousand during and 35·1 thousand after the lockdown), and 1,066·8 (95%CI: 668·7, 1,456·8) thousand fewer YLLs (343·3 thousand during and 723·5 thousand after the lockdown) than these in 2018-2019 in China. Interpretation: The COVID-19 lockdown has caused substantial decrease in air pollutant concentrations except for O3, which has been accompanied by substantial mortality reductions in China. Funding: Key-Area Research and Development Program of Guangdong Province. Declaration of Interests: We declare no competing interests. Ethics Approval Statement: This study was approved by the Ethics Committee of Guangdong Provincial Center for Disease Control and Prevention (W96-027E-2020004).

Supplemental Digital Content is available in the text. Background: Selenium (Se) is an essential element and also toxic at an excessive level for human body. However, few studies have investigated adverse effects of Se exposure on birth weight and placental weight. Methods: All participants were selected from the Prenatal Environment and Offspring Health cohort conducted in 2016 in Guangzhou, China. Se in each participant was measured by inductively coupled plasma mass spectrometry in their urine samples. The urinary Se concentrations were corrected by creatinine and transformed by natural logarithm (ln-Se). Multiple-linear regression models were applied to estimate the associations among Se exposure levels, placenta weight, and birth weight. Results: A total of 2758 mother-newborn pairs were included in this study. Each interquartile range (0.53 μg/g creatinine) increment in urine ln-Se concentration during the first trimester was associated with a mean 21.7 g (95% CI = −41.3g to −2.1g) decrease in birth weight and 3.6g (95% CI = −6.3g to −0.9g) decrease in placental weight. Compared with the lowest quartile (Q1) of ln-Se concentrations during the first trimester, significantly lower birth weight was found in the highest quartile (Q4) (β = −45.7g; 95% CI = −90.7g to −0.7g). Similar dose-response associations with birthweight and placental weight were found for Se exposure during the third trimester. Mediation analyses showed that 44.2% and 18.2% of the effects of Se exposure in first and third trimester on birth weight were mediated by decreased placental weight, respectively. Conclusion: Maternal Se exposure during pregnancy was negatively associated with birth weight, the reduction of placental weight may partially mediate the association of prenatal Se exposure with birth weight.

Dengue fever is regarded as the most prevalent mosquito-borne viral disease in humans. However, information of dengue virus (DENV) infection in pregnant women and the influence factors remain unclear. In this study, we extracted information of 2,076 pregnant women from the Prenatal Environment and Offspring Health (PEOH) birth cohort conducted since 2016 in Guangzhou, China. Peripheral blood and clean midstream urine samples of participants were collected during their hospitalization for childbirth. Indirect enzyme-linked immunosorbent assay (ELISA) was used to detect immunoglobulin G (IgG) antibodies of DENV in serum samples, and inductively coupled plasma mass spectrometry (ICP-MS) was applied to determine the Fe concentrations in the urine samples, which were then adjusted for by urine creatinine and transformed by natural logarithm (ln-Fe). The seroprevalence of DENV IgG antibody in all included participants was 2.22% (46/2,076). We observed higher seroprevalence of IgG antibody in women aged ≥35 years (2.9%), education ≤ 12 years (2.5%), yearly income per capita <100,000 yuan (2.4%), no use of air-conditioner (2.4%), no use of mosquito coils (2.3%), and no exercise during pregnancy (4.1%). A U-shaped relationship was found between ln-Fe concentration and the risk of positive IgG antibody. Compared with women with ln-Fe concentration of 2.0–2.9 μg/g creatinine, slightly higher risks of positive IgG antibody were found among women with ≤2.0 (RR = 4.16, 95% CI: 0.78, 19.91), 3.0–3.9 (RR = 1.93, 95% CI: 0.65, 7.08), 4.0–4.9 (RR = 2.19, 95% CI: 0.65, 8.51), and ≥5.0 μg/g creatinine of ln-Fe (RR = 2.42, 95% CI: 0.46, 11.33). Our findings suggested that the seroprevalence of dengue IgG antibody in pregnant women was comparable to the general population in Guangzhou, China. The risk of DENV infection may be associated with maternal demographic characteristics and behaviors. Both maternal low and high Fe concentrations may be positively associated with the risk of DENV infection.