Maternal asthma and risk of preterm delivery

PURPOSE: We studied the relation between maternal history of asthma and preterm delivery. METHODS: The 312 preterm delivery cases, studied in aggregate, and in subgroups (spontaneous preterm labor, preterm premature rupture of membranes, medically induced preterm delivery), were compared with 424 randomly selected women who delivered at term. Maternal medical records provided information on maternal lifetime asthma status, pregnancy outcome, and sociodemographic characteristics. Using multivariate logistic regression, we derived maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Maternal history of asthma was associated with an increased risk of preterm delivery overall (OR = 2.37; 95% CI 1.15-4.88). Analyses of preterm delivery sub-groups indicated that maternal history of asthma was associated with at least a doubling in risk of spontaneous preterm labor (OR = 2.35; 95% CI 0.84-6.58) and medically induced preterm delivery (OR = 2.69; 95% CI 1.11-6.53), though only the latter approached statistical significance. There was some evidence of a modest association between maternal asthma and risk of preterm premature rupture of membranes (OR = 1.63; 95% CI 0.50-5.33). CONCLUSIONS: These results support the hypothesis that maternal asthma is associated with an increased risk of preterm labor and delivery.     

Alcohol consumption during pregnancy and the risk of preterm delivery

The authors evaluated the association between amount and type of alcohol consumed during pregnancy and the risk of preterm delivery and whether the relation differs among very (<32 completed weeks) and moderate (from 32 to <37 completed weeks) preterm delivery. The study is based on data of 40,892 pregnant women included in the first part of the Danish National Birth Cohort. The women completed a computer-assisted telephone interview between December 12, 1997, and December 31, 2000, and delivered a liveborn singleton. Of these women, 1,880 gave birth preterm. Compared with those who abstained during pregnancy, the relative risks for preterm delivery among women who consumed from four to less than seven drinks and seven or more drinks per week during pregnancy were 1.15 (95% confidence interval: 0.84, 1.57) and 1.77 (95% confidence interval: 0.94, 3.31), respectively. Below these intake levels of alcohol, no increased risk of preterm delivery was found. Among women who consumed seven or more drinks per week, the relative risk of very preterm delivery was 3.26 (95% confidence interval: 0.80, 13.24) compared with that of nondrinkers. There were no differences in the associations between type of beverage and preterm delivery.     

Maternal unemployment: an indicator of spontaneous preterm delivery risk

The aim of this study was to assess the association between maternal employment and preterm delivery. A nationwide case–control study was conducted in 25 Portuguese public maternities. During a 4-month period, 769 consecutive single spontaneous preterm (<37 gestation weeks) live births and 1,053 term singleton babies born immediately after each preterm, were evaluated. Information was obtained by attending physicians using a questionnaire, with special emphasis on maternal work characterization. Logistic regression odds ratios (OR) were adjusted for maternal age, marital status, education and obstetrical characteristics. Women entering pregnancy while unemployed presented a significantly increased risk of spontaneous preterm delivery (OR = 1.5; 95% confidence interval (CI) 1.18–1.88). Weekly duration of work (<40 versus ≥40 h) had no significant effect on the occurrence of spontaneous preterm (OR = 1.2; 95% CI 0.88–1.54). Unemployed women presented a significant increase in the risk of preterm delivery.     

Maternal second-trimester serum ferritin concentrations and subsequent risk of preterm delivery

We studied the relationship between maternal second-trimester serum ferritin concentrations and preterm delivery. The 312 preterm delivery cases, studied in aggregate and in subgroups [spontaneous preterm labour, preterm premature rupture of membranes, medically induced preterm delivery, moderate preterm delivery (gestational age at delivery 34-36 weeks) and very preterm delivery (gestational age at delivery <34 weeks)] were compared with 424 randomly selected women who delivered at term. Maternal ferritin concentrations, measured in serum collected at 17 weeks gestation on average, was determined using a two-site chemiluminometric immunoassay. Using multiple logistic regression, we derived maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals [CI]. Elevation in maternal second-trimester ferritin was weakly associated with the risk of preterm delivery overall. After adjusting for possible confounding by maternal age, race/ethnicity, parity, Medicaid payment status and smoking during the index pregnancy, the OR for extreme quartiles (>64.5 vs. <26.0 ng/mL) of ferritin was 1.3 [95% CI 0.8, 2.1]. Stratified analyses indicated that elevated maternal serum ferritin was associated with an increased risk of preterm premature rupture of membranes (OR = 2.1; 95% CI 1.1, 4.1), but not with spontaneous preterm labour (OR = 0.9; 95% CI 0.4, 1.7) or medically induced preterm delivery (OR = 1.1; 95% CI 0.6, 2.0). The relationship between elevated maternal second-trimester serum ferritin concentrations and preterm delivery was strongest for spontaneous very preterm deliveries (<34 weeks gestation). Women with ferritin concentrations in the highest decile (>96 ng/mL) experienced a 2.7-fold increased risk of delivering before 34 completed weeks, compared with women with concentrations <26.0 ng/mL. These results are consistent with some previous reports, and further underline the potential for heterogeneity in the aetiology of preterm delivery.     

Maternal fish consumption, hair mercury, and infant cognition in a U.S. Cohort

Fish and other seafood may contain organic mercury but also beneficial nutrients such as n-3 polyunsaturated fatty acids. We endeavored to study whether maternal fish consumption during pregnancy harms or benefits fetal brain development. We examined associations of maternal fish intake during pregnancy and maternal hair mercury at delivery with infant cognition among 135 mother-infant pairs in Project Viva, a prospective U.S. pregnancy and child cohort study. We assessed infant cognition by the percent novelty preference on visual recognition memory (VRM) testing at 6 months of age. Mothers consumed an average of 1.2 fish servings per week during the second trimester. Mean maternal hair mercury was 0.55 ppm, with 10% of samples > 1.2 ppm. Mean VRM score was 59.8 (range, 10.9-92.5). After adjusting for participant characteristics using linear regression, higher fish intake was associated with higher infant cognition. This association strengthened after adjustment for hair mercury level: For each additional weekly fish serving, offspring VRM score was 4.0 points higher [95% confidence interval (CI), 1.3 to 6.7]. However, an increase of 1 ppm in mercury was associated with a decrement in VRM score of 7.5 (95% CI, -13.7 to -1.2) points. VRM scores were highest among infants of women who consumed > 2 weekly fish servings but had mercury levels 相似文献   

Toenail mercury and dietary fish consumption

New England is one of three areas in the United States with the highest annual deposition of mercury, an established environmental pollutant with a variety of health effects. We measured the mercury content in toenails of 27 individuals in New Hampshire who participated as controls in a health study in 1994-95. The mean total toenail mercury concentration was 0.27 mcg/g (median 0.16; SD 0.27; range 0.04-1.15 mcg/g). The best predictor of toenail mercury levels was the mean combined fish and shellfish consumption measured using four simple questions from a validated food frequency questionnaire. Toenail total mercury content was significantly correlated with the mean average weekly consumption of finfish and shellfish (Spearman correlation coefficient 0.48, P=0.012). Multivariate models confirmed that toenail total mercury concentration was best predicted by total finfish and shellfish consumption.     

Hair mercury levels, fish consumption, and cognitive development in preschool children from Granada, Spain ,

The main source of human exposure to mercury is the consumption of fish contaminated with methylmercury, which may adversely affect early neurodevelopment. This study assessed mercury levels in hair of preschoolers in Spain, where fish consumption is elevated, with the aim of investigating the influence of their fish intake and other factors on mercury exposure, and evaluating their association with cognitive development. A population-based birth cohort from Granada (Spain) was studied at the age of 4 yr. Total mercury (T-Hg) levels were determined in children's hair, and daily fish intake was assessed by a food frequency questionnaire. The McCarthy Scales of Children's Abilities (MSCA) were used to assess children's motor and cognitive abilities. Complete data were gathered on 72 children, and multivariate analyses were performed to evaluate the influence of mercury exposure and fish intake on MSCA outcomes. Mean concentration of T-Hg in hair was 0.96 μg/g (95% confidence interval=0.76; 1.20 μg/g). T-Hg levels were associated with higher frequency of oily fish consumption, place of residence, maternal age, and passive smoking. After adjustment for fish intake, T-Hg levels ≥1 μg/g were associated with decrements in the general cognitive (−6.6 points), memory (−8.4 points), and verbal (−7.5 points) MSCA scores. Higher mercury exposure in children from this Mediterranean area was associated with cognitive development delay. Studies on the putative benefits of fish intake during early development should consider mercury exposure from different fish species.     

妊娠期空气颗粒物暴露与早产

越来越多的研究证据表明,孕妇妊娠期颗粒物暴露可通过母体影响胎儿的发育,导致早产、低出生体重、胎儿生长受限和潜在的不良心血管和呼吸道结局。但研究结果并不一致,且生物学机制尚不明确。本文通过对近年来国内外主要几种颗粒物人体暴露来源和其对早产影响及生物学机制作一简要综述,为控制空气污染和减少早产等不良妊娠结局的发生以及进一步探讨其可能的生物学机制提供基础依据。     

Hair mercury levels versus freshwater fish consumption in household members of Swedish angling societies

Hair mercury levels were determined in 143 individuals from households of members in angling societies in an area of Sweden with many lakes that have freshwater fish with relatively high mercury levels. Thus, the individuals had a potentially high intake of methyl mercury. The mean mercury concentration of pike and perch was approximately 0.7 microg/g. One-third of the subjects consumed these freshwater fish at least once a week. As could be expected, there was a clear increase in hair Hg with reported freshwater fish consumption (P < 0.001). The median mercury level in hair was 0.9 microg Hg/g for the whole group, and for those who reported consumption of freshwater fish at least once a week it was 1.8 microg/g. The highest hair mercury level was 18.5 microg/g, in a man who consumed pike and perch several times per week. Men had higher hair Hg than women, also when stratified for fish consumption. This was verified in 32 couples, of which the man and woman consumed the same fish and reported the same consumption. The median hair mercury level in these 32 couples was 1.3 microg/g for men and 0.8 microg/g for women (P = 0.002). About half of the subjects had hair mercury exceeding 1 microg/g, corresponding to the reference dose (RfD) of 0.1 microg of mercury per kilogram body weight set by the US Environmental Protection Agency. Although the RfD applies to all populations, the most at-risk group at these levels is pregnant women. There were only 2 women (of 12) of fertile age with hair mercury above 1 microg/g. In Sweden pregnant women are advised not to eat perch and pike at all during pregnancy. Since fish is rich in many important nutrients, it is unsatisfactory that fish consumption must be restricted, and thus there is a need to reduce mercury levels in fish.     

Hair mercury (Hg) levels,fish consumption and semen parameters among men attending a fertility center

General population exposure to methylmercury (MeHg), the most common organic mercury compound found in the environment, occurs primarily through the consumption of contaminated fish and shellfish. Due to limited studies and lack of consideration of effect modification by fish consumption, it remains uncertain if exposure to mercury affects semen parameters. Thus, we investigated whether hair Hg levels, a biomarker of mercury exposure, were associated with semen parameters among men attending an academic fertility center, and whether this relationship was modified by intake of fish.This analysis included 129 men contributing 243 semen samples who were enrolled in the Environment and Reproductive Health (EARTH) Study between 2005 and 2013, and had data of hair Hg, intake of fish and semen parameters available. Hair Hg levels were assessed using a direct mercury analyzer. Intake of fish was collected using a validated food frequency questionnaire. Semen parameters were analyzed following WHO 2010 evaluation criteria. Generalized linear mixed models with random intercepts accounting for within-man correlations across semen samples were used to evaluate the association of hair Hg levels and semen parameters adjusting for age, BMI, smoking status, abstinence time and alcohol intake. Effect modification by total fish intake (≤1.68 vs.?>1.68 servings/week) was tested.The median hair Hg levels of the men was 0.72 ppm and ranged from 0.03 to 8.01 ppm; almost 30% of the men had hair Hg levels >1 ppm. Hair Hg levels were positively related with sperm concentration, total sperm count, and progressive motility, after adjusting for potential confounders and became attenuated after further adjustment for fish intake. Specifically, men in the highest quartile of hair mercury levels had 50%, 46% and 31% higher sperm concentration, total sperm count and progressive motility, respectively, compared to men in the lowest quartile. These associations were stronger among men whose fish intake was above the study population median. Semen volume and normal morphology were unrelated to hair Hg levels.These results confirmed exposure to MeHg through fish intake and showed the important role of diet when exploring the associations between heavy metals and semen parameters among men of couples seeking fertility care. Further research is needed to clarify the complex relationship between fish intake and Hg, and potential effects on male reproductive health, specifically, semen parameters.     

Maternal fish intake during pregnancy, blood mercury levels, and child cognition at age 3 years in a US cohort

The balance of contaminant risk and nutritional benefit from maternal prenatal fish consumption for child cognitive development is not known. Using data from a prospective cohort study of 341 mother-child pairs in Massachusetts enrolled in 1999-2002, the authors studied associations of maternal second-trimester fish intake and erythrocyte mercury levels with children's scores on the Peabody Picture Vocabulary Test (PPVT) and Wide Range Assessment of Visual Motor Abilities (WRAVMA) at age 3 years. Mean maternal total fish intake was 1.5 (standard deviation, 1.4) servings/week, and 40 (12%) mothers consumed >2 servings/week. Mean maternal mercury level was 3.8 (standard deviation, 3.8) ng/g. After adjustment using multivariable linear regression, higher fish intake was associated with better child cognitive test performance, and higher mercury levels with poorer test scores. Associations strengthened with inclusion of both fish and mercury: effect estimates for fish intake of >2 servings/week versus never were 2.2 (95% confidence interval (CI): -2.6, 7.0) for the PPVT and 6.4 (95% CI: 2.0, 10.8) for the WRAVMA; for mercury in the top decile, they were -4.5 (95% CI: -8.5, -0.4) for the PPVT and -4.6 (95% CI: -8.3, -0.9) for the WRAVMA. Fish consumption of < or =2 servings/week was not associated with a benefit. Dietary recommendations for pregnant women should incorporate the nutritional benefits as well as the risks of fish intake.     

Hair mercury concentration and fish consumption: Risk and perceptions of risk among women of childbearing age

The purposes of this study were to assess the hair mercury concentration of women of childbearing age in Taiwan, and to calculate a hazard quotient (HQ) to evaluate the risk of fish consumption for these women. We also examined perceptions of risk associated with fish consumption and whether women in our study changed their habits in response to such risks. The average concentration of mercury was 1.73±2.12 μg g⁻¹ (range: 0.02-16.34 μg g⁻¹), exceeding the US EPA reference dose of 1 μg g⁻¹ in 52.9% of study subjects. The WHO tolerance limit of 10 μg g⁻¹ was exceeded in 1.5% of study subjects. Hair mercury concentration in groups who consumed fish was significantly higher than in groups who never consumed fish (p<0.05). The hazard quotient (exposure estimate/oral reference dose) exceeded 1.0 for 29% of subjects, based on the US EPA’s reference dose (0.1 μg kg⁻¹ d⁻¹), and the average HQ equaled 1.26. When told that some fish contain high levels of mercury that may be harmful for unborn babies, 67.6% of women still indicated that they would not change their amount of fish intake. The high hair mercury concentrations among women of childbearing age in Taiwan are a cause for concern, due to the effect on babies’ brain development. The government should provide specific information about risks and benefits of fish consumption for women to make risk-balancing decisions.     

Work-related physical exertion and risk of preterm, low birthweight delivery

Although many women work during pregnancy, the effect of maternal job experience on pregnancy outcome is controversial. We investigated whether work-related physical exertion increases a woman's risk of delivering a preterm, low birthweight infant. We studied 773 employed, pregnant women included in the National Longitudinal Survey of Labor Market Experience, Youth Cohort (NLSY), a nationally representative sample of young adults. Data concerning work status, job title during pregnancy, and other factors affecting the outcome of pregnancy were obtained from the NLSY. Assessment of physical exertion was based on job title, using an established catalogue of occupational characteristics. Women in jobs characterised by high physical exertion experienced a higher rate of preterm, low birthweight delivery, defined as maternal report of delivery more than 3 weeks early and birthweight under 2,500 g (adjusted RR = 5.1, 95% CI = 1.5, 17.7). These findings support a policy of limiting work-related physical exertion during pregnancy.     

Work-related physical exertion and risk of preterm, low birthweight delivery

Summary. Although many women work during pregnancy, the effect of maternal job experience on pregnancy outcome is controversial. We investigated whether work-related physical exertion increases a woman's risk of delivering a preterm, low birthweight infant. We studied 773 employed, pregnant women included in the National Longitudinal Survey of Labor Market Experience, Youth Cohort (NLSY), a nationally representative sample of young adults. Data concerning work status, job title during pregnancy, and other factors affecting the outcome of pregnancy were obtained from the NLSY. Assessment of physical exertion was based on job title, using an established catalogue of occupational characteristics. Women in jobs characterised by high physical exertion experienced a higher rate of preterm, low birthweight delivery, defined as maternal report of delivery more than 3 weeks early and birthweight under 2 500 g (adjusted RR=5.1, 95% CI=1.5, 17.7). These findings support a policy of limiting work-related physical exertion during pregnancy.     

Hair mercury (signature of fish consumption) and cardiovascular risk in Munduruku and Kayabi Indians of Amazonia

Fish is an important natural resource in the diet of inhabitants of the Amazon rain forest and a marker of its consumption (hair Hg) was used to compare selected cardiovascular risk parameters between tribes of Eastern Amazonia. Three Munduruku (Terra Preta, Kaburua, Cururu) villages and one Kayabi village at the banks of head rivers (Tapajos, Tropas, Kabitutu, Cururu, Curuzinho, Teles Pires) of the Tapajos Basin were studied in relation to fish Hg concentrations, mercury in hair (fish consumption) and erythrocytes, body mass index (height/weight, kg/cm2), and blood pressure. The mean fish Hg concentrations were higher in predatory (578.6 ng/g) than in nonpredatory species (52.8 ng/g). Overall only 26% of fish Hg concentrations were above 500 ng/g, and only 11% were above 1000 ng/g. There was no systematic trend in fish Hg concentrations from rivers with a history of gold-mining activities. The biomarker of fish consumption (hair Hg) was significantly associated with erythrocyte-Hg (r=0.5181; P=0.0001) and was significantly higher in Kayabi (12.7 microg/g) than in the Munduruku (3.4 microg/g). Biomarker-assessed fish consumption rate was higher in the Kayabi (110 g/day) than in the Munduruku villages (30 g/day). Although no significant differences in body mass index (BMI) were observed between tribes, there was a trend of lower increase in blood pressure with age among the higher fish consumers (Kayabi). Summary clinical evaluation did not detect neurologic complaints compatible with Hg intoxication (paraparesis, numbness, tremor, balancing failure), but endemic tropical diseases such as clinical history of malaria showed a high prevalence (55.4%). Fish is an abundant natural resource, important in the Indian diet, that has been historically consumed without perceived problems and can easily be traced through hair Hg. The exposure to freshwater fish monomethyl mercury is less of an issue than endemic infectious diseases such as malaria and lack of basic medical services.     

早产及其相关危险因素的研究

目的:探讨早产及其相关危险因素。方法:纵向随访研究,通过面对面问卷调查,收集妊娠妇女背景资料、孕期个人行为习惯、社会环境因素、妊娠期健康状况等相关信息,随访至分娩,收集妊娠结局资料。数据采用多因素Logistic回归分析方法。结果:711例调查对象中,早产117例(16.46%),发生率较既往报道高。未发现妊娠期个人行为习惯与早产的关系,但年龄增长、工作噪音和胎膜早破与早产明显有关,OR分别为1.43(95%CI:1.05~1.94)、3.38(95%C I:1.21~9.39)、2.14(95%C I:1.19~3.83)。结论:面对早产的高发生率,不应忽略社会环境的潜在影响。对外来务工的妊娠妇女,孕期保健时应常规询问职业状况等因素,以及时发现不利影响,给予适当帮助和指导。     

Fish consumption, fish lore, and mercury pollution--risk communication for the Madeira River people

Fish is an important food resource in Amazonian aquatic ecosystems. There is a strong cultural background regarding fish consumption (fish lore) among indigenous people in the Amazon. Mercury (Hg) ingestion through fish consumption has been a major route of Hg exposure among the riverside people along the Upper Madeira River. In this paper a diet questionnaire was used to identify patterns of fish consumption. The amount of fish consumed during the dry season and Hg levels in fish were combined to estimate Hg ingestion. Using as guidance hair Hg levels below 5 and 10 ppm as acceptable to protect the fetus and adult, respectively, along with an average daily fish consumption of 243 g per capita, we estimated the maximum acceptable number of fish meals per week for different fish species. Based on this analysis, it is suggested that there is a need to address risk communication for this exposed population in the context of health in terms of a fish advisory. For the fish advisory it is necessary to recommend to fish consumers, fishermen, and fish sellers an acceptable number of fish meals to be consumed according to species.     

Maternal periconceptional alcohol consumption and risk of orofacial clefts

Using data from the National Birth Defects Prevention Study, the authors investigated the association between maternal reports of periconceptional alcohol consumption and clefting. Cases with a cleft lip, cleft palate, or both and unaffected controls delivered from 1997 through 2002 were ascertained. Interview reports of alcohol consumption were obtained from 1,749 (75.1%) case and 4,094 (68.2%) control mothers. Adjusted odds ratios and 95% confidence intervals were calculated to assess associations. Compared with odds ratios for mothers with no reported consumption, those for mothers who consumed alcohol tended to be near to (cleft lip, cleft lip with cleft palate) or to exceed (cleft palate) unity. The odds ratios associated with binge drinking were elevated but did not demonstrate significantly increased risk for any phenotype; however, the odds ratios differed by the type of alcohol consumed, particularly for cleft palate (distilled spirits > wine > beer). These odds ratios were further increased among mothers with no reported folic acid intake. Although these findings suggest that the association between alcohol consumption and clefting might be most influenced by the type of beverage consumed and folic acid intake, they are preliminary and might reflect chance associations. Such findings need exploration in additional, large studies.     

Work-related psychosocial stress and risk of preterm, low birthweight delivery.

We investigated whether work-related psychologic stress--defined as work characterized by both high psychologic demands and limited control over the response to these demands--increases a woman's risk of delivering a preterm, low birthweight infant. We studied 786 employed pregnant women included in the National Longitudinal Survey of Labor Market Experience, Youth Cohort (NLSY), a nationally representative sample of 12,686 young adults. Data concerning work status, job title, and other factors affecting pregnancy outcome were obtained from the NLSY. Assessment of job experience was based on job title, using an established catalogue of occupation characteristics. After accounting for the physical exertion entailed in a job, occupational psychologic stress as measured by job title was not associated with preterm, low birthweight delivery for the sample as a whole (Relative risk = 1.16, 95% confidence interval .45, 2.95). For those women who did not want to remain in the work force, work-related stress increased their risk of experiencing this outcome (RR = 8.1, 95% CI 1.5, 50.2). Personal motivation toward work, as well as the physical effort of work, should be considered in evaluating the impact of a job's psychologic characteristics on pregnancy outcome.