Association of pre-/early pregnancy high blood pressure and pregnancy outcomes: a systemic review and meta-analysis.

BACKGROUND: Maternal high blood pressure (BP) was associated with adverse pregnancy outcomes. This study aimed to synthesize evidence on the association between high BP prior to or in early pregnancy with maternal and fetal complications. METHODS: We searched the cohort studies assessing the effect of high BP in the Medline, Embase, Web of Science and China National Knowledge Internet databases. A random-effects model was used to estimate the pooled odds ratios (ORs) with 95% confidence intervals (CIs). The protocol was registered in PROSPERRO (CRD 42023414945). RESULTS: 23 eligible studies were identified. High BP prior to or in early pregnancy was associated with higher odds of hypertensive disorders of pregnancy (OR 2.90, 95% CI 1.91-3.89), gestational hypertension (2.56, 2.01-3.12), preeclampsia (3.20, 2.66-3.74), gestational diabetes mellitus (1.71, 1.36-2.06), preterm birth (1.66, 1.39-1.93), stillbirth (2.01, 1.45-2.58) and neonatal intensive care unit admission (1.22, 1.08-1.37). Subgroup analyses indicated that pre-hypertension could significantly increase the odds of these outcomes except for stillbirth, though the odds were lower than hypertension. CONCLUSIONS: High BP prior to or in early pregnancy was associated with adverse pregnancy outcomes and this association increased with hypertension severity. The findings emphasized an urgent need for heightened surveillance for maternal BP, especially pre-hypertensive status.

Association of age at menarche with gestational hypertension and preeclampsia: A large prospective cohort in China.

This study explored the potential association between age at menarche and the risks of gestational hypertension and preeclampsia in Chinese women. Data were sourced from the China-US Collaborative Project for Neural Tube Defects Prevention, a large population-based cohort study. Our study consisted of 209 411 women pre-registered for pregnancy in two provinces in South China. Trained healthcare workers measured blood pressure at registration and recorded other pertinent health information. Using logistic regression, we assessed the correlations between age at menarche and the likelihood of developing gestational hypertension and preeclampsia, considering confounders such as maternal age, body mass index, ethnicity, parity, folic acid supplementation, education level, and occupation. The observed incidences for gestational hypertension and preeclampsia were 9.65% and 2.54%, respectively. The adjusted odds ratios (ORs) for gestational hypertension, based on age at menarche, were as follows: ≤13 years, 1.18 (95% confidence interval: 1.11-1.26); 14 years, 1.09 (1.04-1.15); 15 years, 1.11 (1.06-1.16); 16 years, 1.06 (1.01-1.12); and ≥17 years, 1.00 (reference; P for trend < .001). The correlation between age at menarche and preeclampsia varied across age groups, with the following respective ORs: 1.35 (1.20-1.52), 1.21 (1.09-1.34), 1.27 (1.15-1.39), 1.14 (1.03-1.26), and 1.00 (reference; P for trend < .001). This association appeared to be more pronounced in women with no folic acid supplementation and those with a lower education level. In conclusion, an earlier age at menarche seems to be linked to increased risks of gestational hypertension and preeclampsia.

Effects of passive smoking on severe nausea and vomiting of pregnancy among urban Chinese nonsmoking women.

Background: Nausea and vomiting of pregnancy (NVP) is one of the most common pregnancy-associated symptoms, but little is known about the effects of passive smoking on this symptom. Passive smoking among women is widespread and severe in China due to the high proportion of men who smoke actively. The aim of this study is to examine the association between maternal passive smoking and severe NVP in early pregnancy among nonsmoking women in urban China. Methods: We collected information on passive smoking status and severe NVP in early pregnancy based on an ongoing prospective cohort study conducted from October 2017 to May 2019 in Beijing, China. We used multivariable logistic model to calculate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) after controlling for confounding factors. Results: Among 3064 participants who were involved in the final analysis, 7.4% (n = 227) were passive smokers and 9.8% (n = 299) reported severe NVP. After adjusting for potential confounders, passive smoking conferred an increased risk of NVP (adjusted OR = 1.62, 95% CI: 1.08, 2.43). The frequency of exposure to second-hand smoke showed a positive relationship with the risk of severe NVP, and significant subgroup differences were also observed in stratified analyses by parity and education level. Conclusions: Our results suggested that maternal exposure to second-hand smoke remained to be a major public health problem in urban China, and that passive smoking during the first trimester may increase the risk of severe NVP among nonsmoking pregnant women. Measures should be taken to reduce the impact of second-hand smoke exposure on pregnant women.

Skin aging associated with chromium among rural housewives in northern China.

Previous studies have found associations between chromium exposure and skin damage. However, few studies have focused on both chromium and skin aging. This study aimed to assess the degree of skin aging symptoms and estimate the relationship between hair chromium and skin aging among rural housewives. We recruited 405 subjects in Shanxi Province of northern China and analyzed 397 eligible hair samples with inductively coupled plasma-mass spectrometry (ICP-MS). The subjects' skin aging symptoms were assessed with SCINEXA™ (SCore of INtrinsic and EXtrinsic skin Aging). After adjusting for age and other important covariates, the regression results showed more severe skin aging symptoms in women with a higher level of hair chromium and presented an increasing linear trend. Vegetables, fruits, and beans might be a source of chromium exposure. We concluded that skin aging might be positively associated with hair chromium. It is necessary to take measures to reduce chromium exposure to prevent skin aging.

Folic acid supplements and perinatal mortality in China.

Introduction: Periconceptional use of multivitamins containing folic acid prevents external major birth defects, especially neural tube defects. We aimed to explore the effects of maternal folic acid supplementation alone on perinatal mortality with or without external major birth defects plus neural tube defects. Methods: From the China-US Collaborative Project for Neural Tube Defects Prevention, we identified 222, 303 singleton pregnancies with detailed information on periconceptional folic acid use, defined as folic acid supplementary before the last menstrual date until to the end of the first trimester. Perinatal mortality included stillbirths after 20 weeks' gestation and early neonatal deaths within 7 days of delivery. Results: Among the fetuses or infants of women who did not take folic acid, the rate of perinatal mortality was 2.99% and 1.62% at least 20 weeks' gestation in the northern and southern regions. Among the fetuses or infants of the women with periconceptional use of folic acid, the rates were 1.85% and 1.39% in the northern and southern region. The estimated relative risk for perinatal mortality [adjusted risk ratio (RR), 0.72; 95% confidence interval (CI), 0.61- 0.85], stillbirth (adjusted RR, 0.78; 95% CI, 0.64-0.96), early neonatal mortality (adjusted RR, 0.61; 95% CI, 0.45-0.82), and neonatal death (adjusted RR, 0.64; 95% CI, 0.49-0.83) in northern China was significantly decreased in association with periconceptional folic acid supplementation. Compared with northern, there was a lesser effect in southern China. Conclusion: Periconceptional intake of 400µg folic acid daily reduces the overall risk perinatal mortality, as well as the risk from external major birth defects and neural tube defects, especially in northern China.

Impact of gestational hypertension and pre-eclampsia on preterm birth in China: a large prospective cohort study.

OBJECTIVE: To investigate the impact of gestational hypertension and pre-eclampsia on preterm birth. DESIGN: The data were collected from the China-US Collaborative Project for Neural Tube Defect Prevention; this was a large population-based cohort study. SETTING AND PARTICIPANTS: We selected participants registered in two southern provinces, for whom we had exact information on gestational blood pressure and pregnancy outcomes, and who were not affected by chronic hypertension. In total, 200 103 participants were recruited from 1993 to 1995. OUTCOME MEASURES: Preterm birth was defined as a singleton pregnancy and birth before 37 gestational weeks. RESULTS: The incidences of gestational hypertension and pre-eclampsia were 5.47% and 5.44%, respectively, for women who gave birth at full term, and 5.63% and 7.33%, respectively, for those who gave birth preterm. After adjusting for potential confounders, the risk ratios (RRs) of preterm birth in women with gestational hypertension and pre-eclampsia were 1.04 (95% CI 0.98 to 1.11) and 1.39 (95% CI 1.25 to 1.55), respectively. The associations were stronger for early-onset (<28 weeks of gestation) gestational hypertension (adjusted RR=2.13, 95% CI 1.71 to 2.65) and pre-eclampsia (adjusted RR=8.47, 95% CI 5.59 to 12.80). CONCLUSIONS: Pre-eclampsia was associated with a higher risk of preterm birth. The early-onset gestational hypertension and pre-eclampsia were associated with more severe risks than late-onset conditions.

Association of Preconception Blood Pressure with the Risk of Anemia in Children under Five Years of Age: A Large Longitudinal Chinese Birth Cohort.

Hypertension during pregnancy may increase the risk of anemia in the offspring. However, few studies have investigated the effects of elevated blood pressure during the preconception period on childhood anemia. This large population-based birth cohort study was performed to determine whether abnormal preconception blood pressure has long-term consequences for childhood health. Data were obtained from the China-US Collaborative Project for Neural Tube Defect Prevention. The study consisted of 40,638 women with singleton live births who were registered in a monitoring system before pregnancy in southern China during the period 1993-1996. Children were assessed by hemoglobin measurement at approximately 53 months of age. The incidences of childhood anemia were 19.80% in the hypertension group and 16.07% in the non-hypertension group. Compared with the non-hypertension group, the hypertension group had an increased risk of childhood anemia (adjusted risk ratio (RR): 1.25; 95% confidence interval (CI): 1.11-1.41). After categorization according to blood pressure, combined systolic and diastolic hypertension was associated with a significantly increased risk of childhood anemia, compared with normotension (adjusted RR: 1.37; 95% CI: 1.16-1.63). Compared with women who had normal blood pressure, the adjusted RRs for childhood anemia were 1.20 (95% CI: 1.13-1.28), 1.26 (95% CI: 1.08-1.47), and 1.38 (95% CI: 1.14-1.67) among women with prehypertension, stage-1 hypertension, and stage-2 hypertension, respectively. Our results suggest a linear association between prepregnancy hypertension and the risk of childhood anemia in the Chinese population. Interventions targeting preconception blood pressure may have a positive effect on childhood health.

Association of gestational hypertension and preeclampsia with nonsyndromic orofacial clefts in China: a large prospective cohort study.

BACKGROUND: The associations between hypertensive disorders of pregnancy and nonsyndromic orofacial clefts (NSOFCs) are not consistent or based on case-control study design. We hypothesize that OFCs and NSOFCs are associated with hypertensive disease in pregnancy. METHODS: Data were collected from the Project for Neural Tube Defects Prevention (1993-1996), a large population-based cohort study conducted in two southern provinces of China. We used a system to record all births after 20 complete gestational weeks, including live births and stillbirths, and all structural congenital anomalies regardless of gestational week. A total of 200 215 singleton live births without other external birth defects were finally included. RESULTS: The incidence of NSOFCs was 20.2 per 10 000 for the whole population, and 20.5 and 39.2 per 10 000 for women with gestational hypertension and preeclampsia, respectively. Compared with the nonpreeclampsia group, preeclampsia was associated with an increased risk of NSOFCs [adjusted risk ratio (RR) = 2.02, 95% confidence interval (CI): 1.27-3.20], cleft lip with or without cleft palate (CL/P) [adjusted RR = 2.24, 95% CI 1.37-3.65], and cleft lip and palate (CLP) [adjusted RR = 2.60, 95% CI 1.45-4.67] but not cleft lip only (CLO) [adjusted RR = 1.66, 95% CI 0.68-4.07] or cleft palate only (CPO) [adjusted RR = 1.09, 95% CI 0.27-4.45]. No associations were observed between gestational hypertension and any types of NSOFCs. CONCLUSION: Our study supported that among hypertensive disorders of pregnancy, only preeclampsia increased the risk of NSOFCs and its subtypes (CL/P and CLP).

Passive Smoking and Risk of Gestational Diabetes Mellitus among Nonsmoking Women: A Prospective Cohort Study in China.

Background: Increasing evidence has shown that active smoking can increase the risk of gestational diabetes mellitus (GDM), but the effect of passive smoking is still unknown. Women in pregnancy are vulnerable to secondhand smoke. This study explored the association of passive smoking with GDM in China. Method: A total of 3083 nonsmoking pregnant women living in Beijing were recruited into a prospective cohort study. Sociodemographic and passive smoking data were collected with structured questionnaires during face-to-face interviews. Glucose levels were measured by physicians according to standard protocols. Multivariate logistic regression was performed for the association estimation after accounting for potential confounders. Result: In total, 562 of the 3083 participants developed GDM (18.23%); 779 participants (25.27%) reported exposure to passive smoking. After adjusting for age, BMI, ethnicity, education, occupation, and parity, passive smoking conferred an approximately 1.4-fold risk increase in GDM (adjusted odds ratio (OR) = 1.37, 95% confidence interval (CI): (1.11, 1.70)). The adjusted ORs with 95% CIs for passive smoking levels of <1, 1−6, and ≥7 times per week were 1.21 (0.94, 1.55), 1.81 (1.22, 2.69), and 1.70 (1.02, 2.84), respectively. An obvious passive-smoking−GDM association was observed among only nulliparous women (adjusted OR = 1.45, 95% CI: (1.14, 1.85)). Conclusion: Frequent exposure to secondhand smoke could increase the risk of GDM among nonsmoking pregnant women. Parity status might modify their association. Public policies should be advocated to prevent passive smoking among this population.

Association of Gestational Hypertension with Anemia under 5 Years Old: Two Large Longitudinal Chinese Birth Cohorts.

Gestational hypertension may interfere with the placental iron metabolism, thus probably increasing the risk of childhood anemia. We aim to examine the association between gestational hypertension and childhood anemia at different ages in two large Chinese birth cohorts. Cohort 1 was conducted in 5 counties in northern China and was comprised of 17,264 mother-children pairs (97.3%) during 2006-2009, whereas cohort 2 was conducted in 21 counties in southern China and was comprised of 185,093 mother-children pairs (93.8%) during 1993-1996. All pregnant women were registered in a monitoring system and followed up until the termination of pregnancies. The childhood anemia was diagnosed at 6 month and 12 month in cohort 1 and at 55 month in cohort 2. The overall incidence of childhood anemia was 6.78% and 5.28% at 6 month and 12 month, respectively, in cohort 1 and 13.18% at 55 month in cohort 2. Gestational hypertension was associated with increased risk of anemia at 6 month (adjusted Odds Ratio (OR): 1.31; 95% confidence interval (CI): 1.05, 1.63) and at 12 month (adjusted OR: 1.50; 95% CI: 1.18, 1.90) in cohort 1 and at 55 month (adjusted OR: 1.06; 95% CI: 1.01, 1.12) in cohort 2. The hemoglobin values of children at different ages were lower among gestational hypertension group in the linear models, which was consistent with the results of binary regression analysis. Our study found gestational hypertension may associate with an increased risk of childhood anemia. It suggests a possible need for exploring changes in prenatal care that might prevent childhood anemia.

Cesarean delivery on maternal request and common child health outcomes: A prospective cohort study in China.

Background: Cesarean delivery vs vaginal delivery was reported to increase the risks of childhood obesity, pneumonia, anemia, and neurobehavioral disorders, but few studies were able to deal with the confounding biases associated with medical conditions indicating cesareans. This prospective cohort study aims to investigate the associations of non-medically indicated cesarean delivery on maternal request (CDMR) with these child health outcomes. Methods: Among 17 748 liveborn infants whose mothers (primiparas) participated in a randomized controlled trial on micronutrient supplementation and pregnancy outcomes during 2006-2009 in 5 rural counties in Hebei Province, China, 6972 singletons born by full-term spontaneous vaginal delivery (SVD) and 3626 by CDMR were extracted for the assessments of obesity (weight-for-height z-score >3) and pneumonia (self-reported) at 1.5-5 years in 2011. Some children were further randomly selected from these two groups for the assessments of anemia (hemoglobin <110 g/L, 2341 SVD and 2417 CDMR) and neurobehavioral disorders (raw score of Child Behavior Checklist larger than the 90th percentile of the normative sample, 1257 SVD and 1060 CDMR). Results: Compared with SVD, CDMR was associated with increased risks of obesity (adjusted odds ratio (aOR) = 1.41, 95% confidence interval (CI) = 1.14-1.75, P = 0.002) and anemia (aOR = 1.65, 95% CI = 1.28-2.12, P < 0.001), but not with the risk of pneumonia (aOR = 1.16, 95% CI = 0.94-1.45, P = 0.17) or neurobehavioral disorders (aORs varied from 0.82 to 0.91, P > 0.05) in childhood. Conclusions: Cesarean delivery, independent of cesarean indications, is likely associated with childhood obesity and anemia, indicating a need to keep pregnant women informed, especially those seeking CDMR, a need to explore possible improvement on obstetric service, and even a need for main stakeholders to reach a compromise in making a cesarean decision. Trial registration: ClinicalTrials.gov: NCT00133744 and NCT01404416.

Association of Infants Small for Gestational Age with Anemia under Five Years Old in Two Large Longitudinal Chinese Birth Cohorts.

Babies who are born small for their gestational age (SGA) have low iron reserves, thus probably increasing the risk of offspring anemia. We studied two longitudinal birth cohorts to evaluate the association of SGA with the risk of anemia during early childhood. Cohort 1 was recruited from five counties in northern China involving 17,180 singleton infants born during 2006-2009 and cohort 2 from 21 counties or cities in southern China involving 180,619 children born during 1993-1996. Anemia was diagnosed by hemoglobin at 6 and 12 months in cohort 1 and at 55 months in cohort 2. The overall incidences of SGA were 7.07% and 5.73% in cohort 1 and cohort 2, respectively. SGA was associated with increased anemia at 6 months (adjusted odds ratio (OR): 1.52; 95% confidence interval (CI): 1.24, 1.86) and 12 months (adjusted OR: 1.42; 95% CI: 1.13, 1.79) in cohort 1 and at 55 months (adjusted OR: 1.11; 95% CI: 1.05, 1.17) in cohort 2. The positive associations for anemia at 6, 12, and 55 months persisted in both logistics and multiple linear models. Our results support a gradually decreased association between SGA and the increased risk of childhood anemia with a longer follow-up time in infants and children.

Preconception Hemoglobin Concentration and Risk of Low Birth Weight and Small-for-Gestational-Age: A Large Prospective Cohort Study in China.

Less is known about the impact of maternal preconception anemia on birth outcomes. We aimed to examine associations between preconception hemoglobin (Hb) concentrations with risk of low birth weight (LBW) and small-for-gestational-age (SGA). This study was from a large population-based prospective cohort in China and included 124,725 women with singleton live births delivered at gestational ages of 28-45 weeks who were registered before pregnancy. Maternal Hb concentrations were measured during registration, and other health-related information was recorded prospectively. Logistic regression was used to evaluate the associations between preconception Hb concentrations with risk of LBW and SGA, adjusting for potential confounders. The results showed women with preconception anemia accounted for 22.28%. The incidences of LBW/SGA were 2.37%/6.30% among anemic women, and 2.01%/5.48% among non-anemic women, respectively. Preconception mild anemia increased by 17% (95% confidence interval (CI): 1.06, 1.28) and 14% (95% CI: 1.07, 1.21) the risk for LBW and SGA, while moderate-to-severe anemia had no significant association with LBW and SGA. Compared with the 120-129 g/L group, a U-shaped association was observed between preconception Hb concentrations with LBW and SGA. In conclusion, not only maternal anemia but also elevated Hb concentrations before pregnancy contribute to an increased risk of LBW and SGA.

Association of Rare Earth Elements with Passive Smoking among Housewives in Shanxi Province, China.

BACKGROUND: Rare earth elements (REEs) are emerging contaminants. Previous studies reported the association between REEs and active smoking, but little is known about the effects of passive smoking on this condition. In China, female passive smoking is widespread, particularly in rural areas. OBJECTIVE: This study aimed to estimate the relationship between REEs accumulation and passive smoking among rural housewives. METHODS: We recruited 385 subjects in Shanxi Province of northern China, of whom 117 housewives were exposed to passive smoking, and 268 were not. We analyzed 15 REEs in the hair of housewives with ICP-MS, including lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium. RESULTS: The results indicated higher levels of 14 REEs except for Sm in both the univariate and adjusted models among the housewives exposed to passive smoking. The increasing linear trend of adjusted odds ratios of 15 REEs supported their association. The Bayesian kernel machine regression (BKMR) models showed that 15 REEs had a significant overall effect, and Eu had a single-exposure effect with passive smoking. CONCLUSION: We concluded that passive smoking might be associated with increased exposure to REEs among rural housewives.

Associations of maternal exposure to 41 metals/metalloids during early pregnancy with the risk of spontaneous preterm birth: Does oxidative stress or DNA methylation play a crucial role?

BACKGROUND: Few studies have explored the effects of multiple types of metals/metalloids on spontaneous preterm birth (SPB). A nested case-control study was conducted in Shanxi Province to investigate the associations between maternal exposure to 41 metals/metalloids during early pregnancy and the risk of SPB, and to clarify the underlying mechanisms of oxidative stress and DNA methylation. METHODS: A total of 74 controls with full-term delivery and 74 cases with SPB were included in the nested case-control study. The metals/metalloids in serum and the DNA adducts in peripheral blood cell DNA were determined using ICP-MS and UPLC-QqQ-MS/MS, respectively. Unconditional logistic regression models were employed to estimate the associations of the risk of SPB with the metal concentrations, as well as with the levels of oxidative stress/DNA methylation. In addition, linear regression models were used to investigate the associations between the metal/metalloid concentrations and the levels of oxidative stress/DNA methylation. RESULTS: After adjusting for potential confounders, the concentrations of Mn, Fe, Cu, Nd, Hg, and Pb in maternal serum during early pregnancy were positively associated with the risk of SPB. Compared with the lowest levels (Quartile 1) of Mn, Fe, Cu, Nd, Hg, and Pb, the odds ratios of SPB increased to 5.21 (95% CI: 1.63, 16.68), 3.47 (95% CI: 1.07, 11.21), 16.23 (95% CI: 3.86, 68.18), 10.54 (95% CI: 2.79, 39.86), 5.88 (95% CI: 1.72, 20.11), and 4.09 (95% CI: 1.31, 12.77) in the highest levels (Quartile 4), respectively. A significant increase in 8-OHdG was associated with the increased exposure to Fe, Pr, Eu, Er, and Lu. The levels of 5-MdC, 5-HmdC, and N6-MdA-the indicators of DNA methylation-were associated with exposure to multiple metals/metalloids. However, no significant associations were observed between the levels of oxidative stress or DNA methylation and the risk of SPB. CONCLUSIONS: Exposure to multiple types of metals/metalloids during early pregnancy is positively associated with the risk of SPB. Oxidative stress and DNA methylation are significantly associated with exposure to multiple metals/metalloids. Systemic oxidative stress and DNA methylation have not been proven to be the mediating mechanisms of metals increasing the risk of SPB.

Associations between hair levels of trace elements and the risk of preterm birth among pregnant Wwomen: A prospective nested case-control study in Beijing Birth Cohort (BBC), China.

Trace elements have various physiochemical functions in humans and are associated with the occurrence of preterm birth (PB). However, their mixed effects on PB risk have rarely been studied. We aimed to investigate the associations between hair levels of trace elements and PB risk among pregnant women. A nested case-control study with a prospective cohort was conducted in Beijing City, China. We included 82 women who had a PB [total PB (tPB)] as cases [including 40 with a spontaneous PB (SPB)] and 415 who had a term delivery as controls. Hair levels of the concerned trace elements were measured including endocrine disrupting metal(loid)s [EDMs; lead, mercury (Hg), arsenic, and cadmium] and nutritional trace metal(loid)s [NTMs; zinc (Zn), iron (Fe), copper, and selenium]. Logistic regression analysis was performed to estimate the odds ratios (ORs) for PB. Bayesian kernel machine regression (BKMR) was used to assess the associations between mixed exposure to the trace elements and PB risk. Significantly lower maternal hair concentrations of Zn and Fe were observed in the SPB cases than in the controls, whereas no differences for the other trace elements. Single-element modeling results suggested second-quartile Hg maternal hair concentrations, third-quartile Zn concentrations, and fourth-quartile Fe concentrations were associated with a reduced risk of tPB with adjusted ORs of 0.43 [95% confidence interval (CI): 0.21-0.87], 0.38 (95% CI: 0.18-0.82), and 0.48 (95% CI: 0.24-0.98), respectively, compared to first-quartile values. Similar results were obtained for SPB. According to the BKMR models, hair NTMs were significantly, monotonously, and inversely associated with the risk of SPB, after controlling for covariates and levels of the four EDMs. Fe and Zn contributed the most strongly to the association. We concluded that maternal higher levels of NTMs, especially Fe and Zn, may reduce the risk of PB.

Thorium and fetal neural tube defects: an epidemiological evidence from large case-control study.

BACKGROUND: Thorium is ubiquitous in the environment and its relationship with birth defects is still under discussion. This study aimed to investigate the associations of maternal exposure to thorium with risk of neural tube defects (NTDs) by using a case-control study, as well as the relationship between thorium exposure and the indoor air pollution from coal combustion. METHODS: This study was conducted in 11 local healthcare hospitals during 2003-2007 in Shanxi and Hebei provinces, China. A total of 774 mothers were included as participants who delivering 263 fetuses with NTDs including 123 with anencephaly, 115 with spina bifida, 18 with encephalocele, and 7 other NTD subtypes (cases), and 511 health fetuses without NTDs (controls). Their hair samples were collected as close as to the occipital posterior scalp, of which those grew from 3 months before to 3 months after conception was cut to measure the thorium concentration by inductively coupled plasma-mass spectrometry. RESULTS: We found a higher hair thorium concentration in the total NTD cases with 0.901 (0.588-1.382) ng/g hair [median (inter-quartile range)] than that in the controls with a value of 0.621 (0.334-1.058) ng/g hair. Similar results were found for the three concerned NTD subtypes. Maternal hair thorium concentration above its median of the controls was associated with an increased risk of the total NTDs with an adjusted odds ratio of 1.80 [95% confidence interval (CI), 1.23-2.63)] by adjusting for all confounders. There was obvious dose-response relationship between maternal hair thorium concentration and the risk of total NTDs, as well as their two subtypes (i.e. anencephaly and spina bifida). Maternal hair thorium concentration was positive associated with their exposure level to indoor air pollution from coal combustion during cooking. CONCLUSIONS: Overall, our findings revealed that maternal periconceptional thorium exposure was associated with the risk of NTDs in North China. Reducing the coal usage in the household cooking activities may decrease maternal thorium exposure level.

Clinical Effects of the COVID-19 Pandemic Among the Uninfected Pregnant Women - 6 PLADs, China, 2019-2020.

SUMMARY: What is already known about this topic? The coronavirus disease 2019 (COVID-19) pandemic potentially affected prenatal care quality and maternal and fetal outcomes globally.What is added by this report? During COVID-19 pandemic period, the rates of caesarean sections (CS) and preterm birth for uninfected pregnant women increased slightly in areas that were relatively severely impacted by the pandemic in China. The overall number of prenatal examinations did not dramatically decrease, while the eligible examinations significantly decreased in Hubei Province.What are the implications for public health practice? Routine prenatal examinations had been well maintained during the pandemic period in China. In the future, in-time prenatal examinations should be provided to improve the quality of screening and management of high-risk pregnancy under pandemic-affected circumstances. Psychological counseling and transfer treatment channels should be strengthened for pregnant women during lockdown period.

Associations between endocrine-disrupting heavy metals in maternal hair and gestational diabetes mellitus: A nested case-control study in China.

BACKGROUND: Exposure to environmental endocrine disruptors (EDCs) may lead to abnormal glucose metabolism and, potentially, gestational diabetes mellitus (GDM). OBJECTIVE: We investigated the association between five endocrine-disrupting heavy metals (EDHMs), i.e., arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and tin (Sn), in maternal hair and the risk of GDM. METHODS: We conducted a nested case-control study including 335 GDM cases and 343 controls without GDM based on a prospective birth cohort established in Beijing, China. Concentrations of EDHMs were analyzed in maternal hair. Log-binomial regression and multiple linear regression were used to estimate the associations between the hair concentrations of single metals and the risk of GDM, while weighted quantile sum (WQS) regression for their mixed effects. RESULTS: The median concentrations of Hg (0.442 vs. 0.403 µg/g) and Sn (0.171 vs. 0.140 µg/g) in the case group were significantly higher than those in the control group. No differences were found between the two groups for the other three metals. After adjusting for confounders, the prevalence ratio (PR; highest vs. lowest tertile) of GDM risk for Hg was 1.27 (95% confidence interval [CI]: 1.05-1.54), while that for Sn was 1.26 (95% CI: 1.04-1.53). Among women with a body mass index < 24 kg/m2, the PR (highest vs. lowest tertile) of GDM for Sn was 1.38 (95% CI: 1.09-1.75). The effect of exposure to the five EDHMs on the risk of GDM was estimated by WQS regression: Sn and Hg made the largest contributions to the WQS index (40.9% and 40.3%, respectively). CONCLUSION: High maternal levels of EDHMs, particularly Sn and Hg, may promote the development of GDM.

Associations between blood heavy metal(loid)s and serum heme oxygenase-1 in pregnant women: Do their distribution patterns matter?

The relationship between heavy metal(loid)s exposure and oxidative stress damage is a matter of research interest. Our study aimed to investigate the distribution patterns of the nine heavy metal(loid)s in blood of pregnant women, including four toxic heavy metal(loid)s [arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg)] and five typical heavy metal(loid)s [manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), and selenium (Se)] in blood. Blood samples of 348 women were collected and their concentrations in the serum (sr) and blood cells (bc) were measured, as well as serum heme oxygenase-1 (HO-1) (an oxidative stress marker). Total blood (tb) concentrations of these metal(loid)s and serum-to-blood cell concentration ratios (sr/bc) were further calculated. We found Cu mainly accumulated in the serum compared to the blood cells with Cusr/bc = 2.30, whereas Co, Se, and As evenly distributed between these two fractions. Other metal(loid)s mainly concentrated in the blood cells. Cosr, Cusr, Cubc, Mnbc, Znbc, Cdbc, Cotb, Cutb, Mntb, Zntb, Cdtb, and Cusr/bc were negatively associated with serum HO-1, whereas Assr, Asbc, Astb, Znsr/bc, Cdsr/bc, and Hgsr/bc were positively, indicating of their potential toxicity. We concluded that the distribution patterns of blood heavy metal(loid)s, in particular for Cd, Hg and Zn, which either increased in serum or decreased in blood cells, might be associated with elevated serum oxidative stress, should be considered in environmental health assessments.