Elevated birth defects in racial or ethnic minority children of women living near hazardous waste sites

This case-control study evaluated the relationship between birth defects in racial or ethnic minority children born during 1983-1988 and the potential exposure of their mothers to contaminants at hazardous waste sites in California. Four categories of race or ethnicity were used: black/African American, Hispanic/Latino, American Indian/Alaska Native, and Asian/Pacific Islander. Case subjects were 13,938 minority infants with major structural birth defects (identified by the California Birth Defects Monitoring Program) whose mothers resided in selected counties at the time of delivery. The control group was composed of 14,463 minority infants without birth defects who were randomly selected from the same birth cohort as the case subjects. The potential for exposure was determined by whether the mother resided at the time of delivery in the same census tract as a hazardous waste site that was on the U.S. Environmental Protection Agency's National Priorities List (NPL). Racial/ethnic minority infants whose mothers had been potentially exposed to hazardous waste were at slightly increased risk for birth defects (odds ratio [OR] = 1.12, 95% confidence interval [CI] = 0.98-1.27) than were racial/ethnic minority infants whose mothers had not been potentially exposed. The greatest association was between potential exposure and neural tube defects (OR = 1.54, 95% CI = 0.93-2.55), particularly anencephaly (OR = 1.85, 95% CI = 0.91-3.75). The strongest association between birth defects and potential exposure was among American Indians/Alaska Natives (OR = 1.19, 95% CI = 0.62-2.27). Despite the limitations of this study, the consistency of these findings with previous studies suggests an association between environmental risk factors and birth defects. This is particularly relevant to minority populations. We recommend further investigation of birth defects among minority communities, particularly among American Indians/Alaska Natives. Special attention should also be paid to those defects and contaminants that consistently are associated with exposure to hazardous waste.     

Maternal active and passive smoking and fetal growth: A prospective study in Nagoya, Japan

In order to examine the effect of maternal active and passive smoking on fetal growth, we carried out a population-based cohort study. A self-administered questionnaire was distributed to 15,207 women who notified their pregnancy from April, 1989 to March, 1991. A total of 7,411 mother-singleton infant pairs were analyzed in this study. Paternal smoking status and maternal hours exposed to environmental tobacco smoke (ETS) were used as indicators of passive smoking. Infants born to active smoking mothers were 96 g lighter, on an average, at birth than those born to non-smokers, and the relative risk for intrauterine growth retardation was 1.79 (95% confidence interval (CI) = 1.05-3.04) among active smoking mothers. Infants with smoking fathers weighted 11 g lighter, on an average, than those with non-smoking fathers, and mean birth weight of infants was reduced by 19 g among mothers exposed to ETS. The relative risk for intrauterine growth retardation in non-smoking pregnants with a smoking husband and those exposed to ETS was 0.95 (95% CI = 0.72-1.26) and 0.95 (95% CI = 0.71-1.26), respectively. Our findings indicated an adverse effect of maternal active smoking on fetal growth in Japanese pregnant population, but with small influence of maternal passive smoking.     

Association of maternal caffeine consumption with decrements in fetal growth

Whether caffeine consumption during pregnancy represents a fetal hazard remains uncertain. The authors report on a large prospective study designed to examine this question. In 1996-2000, 2,291 mothers with singleton livebirths in Connecticut and Massachusetts were evaluated after their first prenatal visit and were questioned about caffeine consumption and important confounding factors. Urine samples were provided to analyze urinary caffeine, cotinine, and creatinine levels. Mothers were followed throughout pregnancy to monitor changes in consumption. Pregnancy outcomes were obtained from medical records. Self-reports of caffeine consumption in the first and third trimesters were not associated with intrauterine growth retardation, low birth weight, or preterm delivery. For every 1 mg/g creatinine increase in urinary caffeine, risk of intrauterine growth retardation was essentially unchanged (odds ratio (OR) = 0.96, 95% confidence interval (CI): 0.85, 1.08). In contrast, a 0.005 mg/g creatinine increase in urinary cotinine significantly increased risk (OR = 1.003, 95% CI: 1.001, 1.005). Mean birth weight was reduced by reported caffeine consumption (-28 g per 100 mg of caffeine consumed daily, 95% CI: -0.10, -0.46, p = 0.001) but not mean gestational age. Decaffeinated coffee did not increase risk for any perinatal outcome. This small decrease in birth weight, observed for maternal caffeine consumption, is unlikely to be clinically important except for women consuming >/=600 mg of caffeine daily (approximately six 10-ounce (1 ounce = 28.3 g) cups of coffee).     

Pregnancy complications and subsequent maternal cerebrovascular events: a retrospective cohort study of 119,668 births

Low birth weight infants are at increased risk of cerebrovascular disease in adulthood. This has been attributed to physiologic programming following inadequate intrauterine nutrition. The authors sought to determine whether mothers who deliver low birth weight infants or who suffer related pregnancy complications are also at increased risk. They used routine data to identify all first singleton livebirths in Scotland (1981-1985) and found that 342 of the 119,668 mothers suffered cerebrovascular events over 14-19 years' follow-up. Compared with women who delivered babies of > or = 3,500 g, women who delivered low birth weight (<2,500 g) infants were at increased risk of cerebrovascular disease (adjusted hazards ratio (HR) = 2.51, 95% confidence interval (CI): 1.71, 3.70) with a consistent trend across birth weight categories. The lowest birth weight quintile (adjusted HR = 1.29, 95% CI: 1.01, 1.65), preterm delivery (adjusted HR = 1.91, 95% CI: 1.35, 2.70), and previous spontaneous abortion (adjusted HR = 1.49, 95% CI: 1.09, 2.03) were all predictive of subsequent maternal cerebrovascular events. The effects were additive. Women who experienced all three complications had a sevenfold risk (adjusted HR = 7.03, 95% CI: 2.24, 22.06). The association with low birth weight in mothers, as well as offspring, is unlikely to be explained by intrauterine programming and suggests that cerebrovascular disease and low birth weight may share common genetic or lifestyle risk factors.     

Caffeine consumption during pregnancy and fetal growth.

BACKGROUND: The purpose of this study was to examine the association between maternal caffeine consumption and low birthweight, intrauterine growth retardation, and prematurity, adjusting for multiple confounders. METHODS: Data obtained from birth certificates and interviews on 1,230 women with singleton live births were analyzed to evaluate the potential influence of caffeine consumption during the first trimester on fetal growth. RESULTS: The crude odds ratio for intrauterine growth retardation in infants of women reporting heavy caffeine consumption (greater than 300 mg/day) was 3.86 (95% CI = 1.80, 8.40) which decreased to 2.90 (95% CI = 1.23, 6.87) after controlling for confounding factors. The adjusted odds ratio for low birthweight and heavy maternal caffeine consumption was also elevated (OR = 2.05; 95% CI = 0.86, 4.88). Women who reduced their caffeine intake from greater than 300 mg/day to less than that early in pregnancy had lower risks of delivering infants with either intrauterine growth retardation or low birthweight than women who continued to consume that amount. Preterm delivery appeared to be unrelated to caffeine consumption. CONCLUSIONS: Taken together with studies reporting similar findings, these results suggest that heavy caffeine consumption increases the risk for fetal growth retardation.     

Risk of low birthweight and prematurity among foreign-born mothers.

Data collected during postnatal visits were used to study the risk of low birthweight (LBW) and prematurity among foreign-born mothers and mothers born in Canada. 2,913 singleton live births were included in the analysis. Odds ratios (OR) and 95% confidence intervals (CI) for LBW and prematurity were estimated using a logistic regression model. Foreign-born mothers did not have a higher risk of LBW or prematurity as compared to native-born mothers (OR = 1.1, 95% CI = 0.8-1.5; OR = 1.0, 95% CI = 0.7-1.4, respectively). For both LBW and prematurity, women in the intermediate category of length of stay (1-3 years) had a somewhat lower risk and women with the shortest length of stay (less than one year) had a slightly higher risk than women with the longest length of stay (more than 3 years). However, none of these results was statistically significant. Results of this study suggest that foreign-born mothers do not have a higher risk than Canadian-born mothers of bearing a LBW or premature infant. This finding differs from the widespread perception that immigrant mothers are at high risk for adverse birth outcomes.     

Energy intake,maternal nutritional status and intrauterine growth retardation

To explore the association between low caloric intake during pregnancy and intrauterine growth retardation (IUGR), a case-control study with 264 cases and 892 controls was conducted in three maternity hospitals in Mexico City from January to August 1995. Nutritional information on pregnancy was recorded using a previously validated food frequency questionnaire. After adjusting for other known maternal risk factors in the non-conditional logistic regression analysis, for the total sample, caloric intake did not present a direct effect on IUGR (OR: 0.99; CI 95%: 0.99-1.00). However the odds ratios were as follows for women: with low pre-gestational weight (OR: 2.31; CI 95%: 1.59-3.36), in first gestation (OR: 1.72; CI 95%: 1.18-2.51), with low birth weight infants (OR: 3.54; CI 95%: 1.93-6.46), and presenting hypertension during pregnancy (OR: 1.61; CI 95%: 1.00-2.59).     

Ethnic-cultural background, maternal body size and pregnancy outcomes in a diverse Swiss cohort

OBJECTIVE: To investigate the influence of ethnic-cultural background and maternal body size on pregnancy outcomes in infants born at term. STUDY DESIGN: A retrospective cohort of 1,432 pregnant women who delivered a live newborn at term between 1999 and 2003 provided the data for the following study. We performed multivariable regression analyses for birth weight and rate of caesarean section controlling for body mass index (BMI), net weight gain, maternal age, parity, smoking, marital status and sex of infant. RESULTS: Thirty percent of the women studied had a BMI > or = 25; the proportion of mothers with a BMI > or = 25 varied substantially by ethnic-cultural background (range: Far East 2.8% vs. Africa 50.0%). After adjustment for confounding variables, mothers from Sri Lanka and the Middle East had significantly lighter infants (Sri Lanka -145.5 g, 95% CI -59.3 g to -231.7 g, P = 0.001; Middle East -214.3 g, 95% CI -33.7 g to -395.0 g, P = 0.02) than mothers from Switzerland. Each unit increase in maternal pre-pregnancy BMI was associated with a 20.3 g increase in birth weight (95% CI 14.3 g to 26.4 g, P < 0.001). Muslim mothers from the former Yugoslavia had significantly lower odds of caesarean section than Swiss mothers (OR 0.63, 95% CI 0.41 to 0.96, P = 0.03). CONCLUSIONS: In this cohort, certain ethnic-cultural groups had increased odds for low birth weight and others had reduced odds of operative delivery compared with the Swiss comparison group. Given the strong association between ethnic-cultural background and overweight in this cohort, culturally appropriate support and counseling during prenatal care should be evaluated in the increasingly diverse environment in European countries.     

0～24月龄婴幼儿过敏性疾病的宫内致敏因素研究

目的 了解0～24月龄内婴幼儿过敏性疾病的流行现状,探讨该疾病与宫内致敏因素的关系,为预防婴幼儿过敏性疾病的发生提供理论依据。方法 采用巢式病例对照研究的方法,选取2015年9月—2017年6月于四川大学华西第二医院生产的母婴作为研究队列,婴幼儿0～24月龄发生过敏性疾病的母婴作为病例组,以母亲生产年龄与病例组±2岁、生产方式、婴幼儿性别、婴幼儿出生体重与病例组±0.5 kg、出生身长±1㎝为条件按照1:3匹配队列中的其他研究对象为对照组,分析0～24月龄内婴幼儿过敏性疾病的宫内致敏因素。结果 本次研究中共纳入3 018对母婴,其中,24月龄内有380例婴幼儿发生了过敏性疾病,累积发病率为12.6%。多因素条件logistic回归分析发现24月龄内的宫内致敏危险因素有：祖父母过敏史（OR=1.47,95%CI:1.00～2.16）、经常接触动物毛屑（OR=1.76,95%CI:1.16～2.69）或昆虫（OR=2.85,95%CI:1.75～4.64）、食用坚果频率>4次/月（OR=1.61,95%CI:1.15～1.26）。结论 祖父母过敏史、母亲孕期经常接触昆虫和动物毛屑、经...     

Enigma of maternal race and infant birth weight: a population-based study of US-born Black and Caribbean-born Black women

The authors used 1985-1990 Illinois' vital records to determine the low birth weight components of infants delivered to US-born Black women, Caribbean-born Black women, and US-born White women. The moderately low birth weight rate (1,500-2,499 g) was 10% for infants with US-born Black mothers (n = 67,357) and 6% for infants with Caribbean-born mothers (n = 2,265) compared with 4% for infants with US-born White mothers (n = 34,124); the relative risk equaled 2.7 (95% confidence interval (CI): 2.5, 2.8) and 1.7 (95% CI: 1.4, 2.0), respectively. The very low birth weight rate (<1,500 g) was 2.6% for infants delivered to US-born Black women and 2.4% for infants to Caribbean-born women compared with 0.7% for infants to US-born White women; the relative risk equaled 3.6 (95% CI: 3.1, 4.1) and 3.3 (95% CI: 2.5, 4.4), respectively. Among the lowest risk mothers, the relative risk of moderately low birth weight for infants with US-born Black mothers and Caribbean-born mothers (compared with US-born White mothers) was 2.7 (95% CI: 2.1, 3.4) and 1.2 (95% CI: 0.4, 3.1), respectively; the relative risk of very low birth weight for infants with US-born Black mothers and Caribbean-born mothers was 6.7 (95% CI: 3.8, 12) and 4.2 (95% CI: 1.0, 18), respectively. The authors conclude that Caribbean-born women and US-born Black women have disparate moderate rates but equivalent very low birth weight rates.     

泰安市乙型肝炎病毒宫内传播影响因素分析

目的　探讨泰安市乙型肝炎病毒表面抗原（HBsAg）阳性母亲分娩的新生儿发生乙型肝炎病毒（HBV）宫内跨胎盘传播的影响因素。方法　纳入567例HBsAg阳性母亲及其新生儿作为研究对象,收集母亲一般信息及抗病毒治疗等资料,检测母亲及新生儿HBV标志物、HBV DNA等指标。统计分析采用χ2检验和非条件多因素logistic回归。结果　泰安市HBsAg阳性母亲所分娩的新生儿HBV宫内传播的发生率为11.46%。单因素分析显示母亲年龄、孕晚期乙型肝炎免疫球蛋白干预、乙型肝炎病毒e抗原（HBeAg）、HBV DNA浓度和HBV基因型与新生儿宫内传播的发生有关（P<0.05）。Logistic回归分析显示,母亲HBeAg（OR=3.350,95%CI=1.889~6.964）和HBV DNA浓度（OR=2.096,95%CI=1.585~5.508）是HBV宫内传播的影响因素。以阴性为对照,母亲HBV DNA低载量组调整OR值为1.211（95%CI:1.110~1.565）,高载量组调整OR值为1.948（95%CI:1.345~2.784）,母亲HBV DNA浓度与宫内传播之间存在线性趋势（χ2=6.920,P=0.009）。结论　HBsAg阳性母亲伴HBeAg阳性和高HBV DNA浓度是造成泰安市HBV宫内跨胎盘传播的主要危险因素,且HBV DNA浓度越高,发生宫内传播的可能性越大。     

Maternal, delivery, and perinatal characteristics associated with cryptorchidism: a population-based case-control study among births in Washington State

BACKGROUND: The etiology of cryptorchidism is largely unknown. To identify maternal, perinatal, and delivery characteristics associated with cryptorchidism at birth, we conducted a population-based case-control study using Washington State birth certificates linked to birth hospitalization records. METHODS: We identified 2,395 cases of cryptorchidism among male infants born in Washington State during 1986-1996, and, for comparison, we randomly selected four controls per case (N = 9,580), frequency-matched by year of birth. RESULTS: Infant characteristics associated with cryptorchidism included low birth weight (OR = 1.5; 95% CI = 1.3-1.8), small size for gestational age (OR = 1.9; 95% CI = 1.6-2.2), and breech presentation (OR = 1.7; 95% CI = 1.4-2.1). In addition to cryptorchidism, cases were more likely to have another type of congenital malformation (OR = 3.7; 95% CI = 3.2-4.2), particularly digestive (OR = 6.8; 95% CI = 3.7-12.7) or genitourinary (OR = 4.1; 95% CI = 3.0-5.6). Maternal and pregnancy characteristics associated with cryptorchidism included nulliparity (OR = 1.2; 95% CI = 1.1-1.3), maternal smoking during pregnancy (OR = 1.2; 95% CI = 1.1-1.4), and the following pregnancy complications: oligohydramnios (OR = 1.8; 95% CI = 1.3-2.6), placental abnormality (OR = 1.3; 95% CI = 1.0-1.8), and pregnancy-induced hypertension (OR = 1.6; 95% CI = 1.4-1.9). Odds ratios were similar when the analysis was restricted to term infants. CONCLUSIONS: These findings suggest that factors affecting fetal growth and development may increase the risk of cryptorchidism.     

Association between drinking water disinfection and somatic parameters at birth.

We conducted an epidemiological study in Liguria, Italy, on the association between somatic parameters at birth and drinking water disinfection with chlorine dioxide and/or sodium hypochlorite. Over 2 years (1988-1989), 676 births at two public hospitals, one in Genoa (548 cases) and another in Chiavari (128 cases) were examined and data regarding both mother and child were obtained from hospital records. Results indicate a higher frequency of small body length (< or = 49.5 cm) and small cranial circumference (< or = 35 cm) in infants born to mothers who drank water treated with chlorine compounds. In particular, the statistical analysis (by simultaneous variance analysis and Scheffé test) indicated that there may be an association between infants with smaller body length and mothers who drank water treated with chlorine dioxide [adjusted odds radio (OR) = 2.0; 95% CI = 1.2-3.3] or sodium hypoclorite (adjusted OR = 2.3; 95% CI = 1.3-4.2) and between infants with smaller cranial circumference and mothers who drank water treated with chlorine dioxide (adjusted OR = 2.2; 95% CI = 1.4-3.9) or sodium hypochlorite (adjusted OR = 3.5; 95% CI = 2.1-8.5). The presence of neonatal jaundice is almost twice as likely (adjusted OR = 1.7; 95% CI = 1.1-3.1) in infants whose mothers drank water treated with chlorine dioxide.     

A case-control study of maternal alcohol consumption and intrauterine growth retardation

PURPOSE: Heavy maternal drinking during pregnancy causes fetal alcohol syndrome, but whether more moderate alcohol consumption is associated with such adverse pregnancy outcomes as intrauterine growth retardation (IUGR) remains controversial. METHODS: Using data from a case-control study, we examined the association between maternal alcohol consumption and risk for IUGR among 701 case and 336 control infants born during 1993-1995 in Monroe County, New York. RESULTS: Our results provide no evidence of an independent association between moderate maternal alcohol consumption (<14 drinks per week) and risk for IUGR. The risk for IUGR among heavy drinkers (> or =14 drinks per week) around the time of conception was OR = 1.4 (95% CI 0.7-2.6) for IUGR < or = 5th percentile and OR = 1.4 (95% CI 0.7-2.8) for IUGR 5th-10th percentile. For heavy drinkers during the first trimester, the OR was 1.3 (95% CI 0.4-4.5) for IUGR < or = 5th percentile and OR = 1.3 (95% CI 0.4-4.8) for IUGR 5th-10th percentile. CONCLUSIONS: Since IUGR is a heterogeneous outcome with a possible multifactorial origin, further studies are needed to examine the combined effects of alcohol and other environmental and genetic factors on IUGR risk for subgroups of IUGR.     

人类免疫缺陷病毒感染孕产妇所产婴儿死亡的影响因素分析

目的 了解我国获得性免疫缺陷综合征(AIDS)高流行地区人类免疫缺陷病毒(HIV)感染孕产妇所产婴儿死亡的影响因素.方法 结合2004年建立的HIV感染孕产妇及所产婴儿随访研究队列,于2008年8-11月对我国4省7县区2004年1月至2007年11月HIV感染孕产妇所产婴儿的死亡状况及其影响因素进行调查.实际收集了498对HIV感染孕产妇及所产婴儿的相关信息.采用单因素和多因素Cox比例风险模型对HIV感染孕产妇所产婴儿死亡的影响因素进行分析.结果 498名婴儿,总观察人年数为406.22人年,死亡45例,死亡密度为110.78/1000人年.单因素分析结果显示,母亲孕产期处于AIDS前期或发病期(RR=1.971,95%CI值:1.143～3.396)、孕产妇生存状况(RR=3.062,95%CI值:1.097～8.550)、经产妇(RR=0.517,95%CI值:0.278～0.961)、自然分娩(RR=0.561,95%CI值:0.345～0.910)、早产(RR=5.302,95%CI值:2.944～9.547)、低出生体重(RR=4.920,95%CI值:2.691～8.994)、母子预防性服用抗逆转录病毒药物(RR=0.227,95%CI值:0.121～0.428)及婴儿感染HIV(RR=5.870,95%CI值:3.232～10.660)等因素影响HIV感染孕产妇所产婴儿的死亡.进一步的多因素分析显示,处于AIDS前期或发病期的孕产妇较处于AIDS潜伏期者所产婴儿死亡危险增加(RR=6.99,95%CI值:1.92～25.64);孕产期CD4~+T淋巴细胞计数低于200个/μl的孕产妇,所产婴儿发生死亡的危险增加(RR=2.05,95%CI值:1.01～4.15);母子未预防性服用抗逆转录病毒药物增加婴儿死亡的危险(RR=6.17,95%CI值:1.62～23.26);早产婴儿死亡危险是足月产婴儿的2.87倍(95%CI值:1.12～7.35);HIV感染婴儿死亡危险是非HIV感染婴儿的9.87倍(95%CI值:3.81～25.62).结论 提高HIV感染孕产妇自身免疫力,降低HIV母婴传播率及HIV感染孕产妇所产婴儿早产、低出生体重的发生率有助于降低婴儿死亡率.     

Association between gaseous ambient air pollutants and adverse pregnancy outcomes in Vancouver, Canada

The association between ambient air pollution and adverse health effects, such as emergency room visits, hospitalizations, and mortality from respiratory and cardiovascular diseases, has been studied extensively in many countries, including Canada. Recently, studies conducted in China, the Czech Republic, and the United States have related ambient air pollution to adverse pregnancy outcomes. In this study, we examined association between preterm birth, low birth weight, and intrauterine growth retardation (IUGR) among singleton live births and ambient concentrations of sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone in Vancouver, Canada, for 1985-1998. Multiple logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for such effects. Low birth weight was associated with exposure to SO2 during the first month of pregnancy (OR = 1.11, 95% CI, 1.01-1.22, for a 5.0 ppb increase). Preterm birth was associated with exposure to SO2 (OR = 1.09, 95% CI, 1.01-1.19, for a 5.0 ppb increase) and to CO (OR = 1.08, 95% CI, 1.01-1.15, for a 1.0 ppm increase) during the last month of pregnancy. IUGR was associated with exposure to SO2 (OR = 1.07, 95% CI, 1.01-1.13, for a 5.0 ppb increase), to NO2 (OR = 1.05, 95% CI, 1.01-1.10, for a 10.0 ppb increase), and to CO (OR = 1.06, 95% CI, 1.01-1.10, for a 1.0 ppm increase) during the first month of pregnancy. In conclusion, relatively low concentrations of gaseous air pollutants are associated with adverse effects on birth outcomes in populations experiencing diverse air pollution profiles.     

Effect of trihalomethane exposure on fetal development

Aims: To examine the effect of trimester specific and pregnancy average total trihalomethane (TTHM) exposure on infant birth weight, low birth weight, and intrauterine growth retardation in term births, as well as gestational age and preterm delivery in all births.

Methods: Cross sectional analysis of 56 513 singleton infants born to residents of Massachusetts during 1990. City specific aggregate data were used to estimate maternal exposure to TTHM concentration; individual maternal information was used to adjust for confounding.

Results: Increased pregnancy average and second trimester TTHM exposure were associated with small for gestational age and reductions in birth weight after adjusting for potential confounding variables. Compared to ≤60 µg/l, pregnancy average TTHM exposure over 80 µg/l was associated with a 32 g reduction in birth weight. There was a 23 g reduction in birth weight in infants born to mothers exposed to greater than 80 µg/l TTHM during the second trimester. For each 20 µg/l increase in TTHM, the estimated reduction in birth was 2.8 g for pregnancy average exposure and 2.6 g for second trimester exposure. An increased risk of small for gestational age births was found for pregnancy average (odds ratio (OR) 1.14; 95% CI 1.02 to 1.26) and second trimester (OR 1.13, 95% CI 1.03 to 1.24) TTHM levels greater than 80 µg/l. There was no evidence of an association between preterm delivery and increased TTHM levels, but there were slight increases in gestational duration associated with TTHM concentrations.

Conclusions: Maternal exposure to THMs may be associated with fetal growth retardation. Our findings are consistent with most previous work, although we generally found smaller effects of TTHMs on low birth weight and intrauterine growth retardation.

     

Maternal smoking during pregnancy and the risk of congenital urinary tract anomalies.

To study maternal smoking during pregnancy and the risk of congenital urinary tract anomalies, we interviewed mothers of 118 affected infants born to residents of western Washington State during 1990 and 1991 and mothers of 369 control infants randomly selected from those without birth defects delivered during those years in five hospitals in King County, Washington. Maternal smoking was associated with an increased risk of congenital urinary tract anomalies in offspring (adjusted odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.2, 4.5). This risk was higher among light smokers (1-1000 cigarettes during the pregnancy) (OR = 3.7; 95% CI = 1.7, 8.6) than among heavy smokers (OR = 1.4; 95% CI = 0.6, 3.3). Our results corroborate previous findings and support the hypothesis of a causal relation.     

Low birth weight in Spain associated with sociodemographic factors.

STUDY OBJECTIVE--To describe the effect of different social and demographic characteristics on low birth weight (LBW) (less than 2500 g) in Spain, in both preterm (less than 37 weeks' gestation) and term infants (between 37 and 42 weeks' gestation). DESIGN--The study used data obtained from the Spanish birth registry. SETTING--The study was based on those live born infants registered in 1988 from provinces where the birthweight details were completed in at least 99.5% of the birth registration records. PARTICIPANTS--A total of 1332 preterm LBW infants, 1292 term LBW infants, and 38,967 controls were included in the study. MEASUREMENTS AND MAIN RESULTS--The odds ratio (OR) calculated by logistic regression was used as the measure of association between LBW and the sociodemographic variables. The highest ORs of preterm LBW were found in mothers younger than 20 years (1.32; 95% CI 0.98, 1.77) and older than 34 years (1.28; 95% CI 1.04, 1.59), in unmarried mothers (1.68; 95% CI 1.36, 2.07), and in fathers with manual occupations (1.26; 95% CI 1.08, 1.46). In term, live born infants the highest ORs were found in adolescent mothers (1.63; 95% CI 1.25, 2.14), in first born live born infants (1.38; 95% CI 1.09, 1.74) or the fourth born or more (1.28; 95% CI 0.91, 1.80), in unmarried mothers (1.55; 95% CI 1.27, 1.90), in housewives (1.13; 95% CI 0.99, 1.29), and in fathers with manual occupations (1.21; 95% CI 1.04, 1.42). CONCLUSIONS--The results have allowed documentation of the risk of preterm and term LBW in various age and social groups in Spain.     

Birth outcomes and prenatal exposure to ozone, carbon monoxide, and particulate matter: results from the Children's Health Study

Exposures to ambient air pollutants have been associated with adverse birth outcomes. We investigated the effects of air pollutants on birth weight mediated by reduced fetal growth among term infants who were born in California during 1975-1987 and who participated in the Children's Health Study. Birth certificates provided maternal reproductive history and residence location at birth. Sociodemographic factors and maternal smoking during pregnancy were collected by questionnaire. Monthly average air pollutant levels were interpolated from monitors to the ZIP code of maternal residence at childbirth. Results from linear mixed-effects regression models showed that a 12-ppb increase in 24-hr ozone averaged over the entire pregnancy was associated with 47.2 g lower birth weight [95% confidence interval (CI), 27.4-67.0 g], and this association was most robust for exposures during the second and third trimesters. A 1.4-ppm difference in first-trimester carbon monoxide exposure was associated with 21.7 g lower birth weight (95% CI, 1.1-42.3 g) and 20% increased risk of intrauterine growth retardation (95% CI, 1.0-1.4). First-trimester CO and third-trimester O3 exposures were associated with 20% increased risk of intrauterine growth retardation. A 20-microg/m3 difference in levels of particulate matter < or = 10 microm in aerodynamic diameter (PM10) during the third trimester was associated with a 21.7-g lower birth weight (95% CI, 1.1-42.2 g), but this association was reduced and not significant after adjusting for O3. In summary, O3 exposure during the second and third trimesters and CO exposure during the first trimester were associated with reduced birth weight.