Psychosocial factors, lifestyle, and fetal growth: the added value of both pre- and post-natal assessments

BACKGROUND: Psychosocial resources as well as lifestyle habits during pregnancy have been shown to effect the risk of having a small-for-gestational-age (SGA) child. Most previous studies are based on a single assessment of these exposures, which does not take into account the possibility of different effects during early and late stages of pregnancy. METHODS: The impact of psychosocial and lifestyle factors on the risk of giving birth to an SGA child (as measured by ultrasound) was examined among 747 nulliparous Swedish women who completed both a prenatal baseline, and a post-partum assessment. RESULTS: Those registering low social participation on both assessments showed increased risk of giving birth to an SGA infant (OR = 2.44 and 95% CI: 1.06-5.66), while at one assessment (OR = 1.70 and 95% CI: 0.74-3.91). Maternal smoking confirmed by both or one assessments yielded an OR = 2.72 and 95% CI: 1.37-5.39 and OR = 1.60 and 95% CI: 0.58-4.46, respectively. During early pregnancy, poor instrumental support, maternal smoking, or passive smoking yielded increased risks of SGA, adjusted for confounding (OR = 2.39 and 95% CI: 1.11-5.17; OR = 2.38 and 95% CI: 1.27-4.49; OR = 2.92 and 95% CI: 1.17-7.32, respectively). In late pregnancy, only maternal smoking yielded a significant association (OR = 2.34 and 95% CI: 1.24-4.41). CONCLUSION: Scheduling repeated assessments of psychosocial resources and lifestyle factors during pregnancy yielded additional information. The findings suggest that there can be differential effects of such exposures depending on gestational stage. This information is of importance when designing appropriate intervention strategies for maternal health services as well as for public health relevant policy formulation (e.g. regarding exposure to environmental tobacco during pregnancy).     

Risk factors for pregnancy-related mortality: a prospective study in rural Nepal

OBJECTIVES: This study examined the risk factors of mortality related to pregnancy for the first year post partum in a cohort of 25,580 pregnancies. STUDY DESIGN: Longitudinal cohort follow-up. METHODS: Details of socio-economic status, mid-upper arm circumference (MUAC), diet, illness, work, substance use and previous pregnancy history were collected during early to mid-gestation, and these women were followed for 1 year post partum. All-cause mortality rates per 100,000 pregnancies were calculated for deaths during pregnancy or up to 42 days post partum (early period) and 43-364 days post partum (late period). Odds ratios (OR) of mortality were estimated using five groups of risk factors: biological; morbidity; dietary; lifestyle; and socio-economic. Significant factors within each group were included in a single risk model for each time period. RESULTS: Early and late pregnancy-related mortality rates were 469 [95% confidence interval (CI) 385-553] and 254 (95% CI 192-316), respectively. Maternal age > or = 35 years was associated with a three- to four-fold increase in mortality, whereas increasing parity conferred increasing protection. In the final model, a larger MUAC and consumption of dark green leaves were associated with decreased risk of death in the early period (OR 0.76, 95% CI 0.67-0.87 and 0.64, 95% CI 0.41-0.99, respectively). A larger MUAC was also associated with a lower risk of death in the late period. Diarrhoea/dysentery and pre-eclampsia were associated with increased risk of death in the early period (OR 2.78, 95% CI 1.40-5.51 and 2.95, 95% CI 1.48-5.90, respectively). Factors weakly associated (P<0.1) with mortality in both periods included night blindness, strenuous work activity and cigarette smoking. No socio-economic factors were significant in the models. CONCLUSIONS: Maternal age, parity, MUAC, diet and illness in early to mid-gestation were associated with risk of death during pregnancy and the first year post partum in rural Nepal.     

母亲孕期铁营养与子代先天性心脏病关系的病例对照研究

  目的  探讨母亲孕期铁营养与子代先天性心脏病(congenital heart disease,CHD)的关系。  方法  数据来源于陕西省2014年1月―2016年12月开展的CHD病例对照研究,对纳入孕妇进行膳食营养问卷调查。采用条件logistic回归分析模型分析母亲孕期铁营养与子代CHD及其各亚型的关系,并进行亚组分析探索其稳定性。  结果  在调整了混杂因素后,母亲孕期增补铁剂降低了子代CHD的发生风险(< 30 d:OR=0.54, 95% CI: 0.37~0.79;≥30 d:OR=0.25, 95% CI: 0.16~0.38),孕期膳食铁摄入量较高(≥29 mg/d)降低了子代CHD的发生风险(OR=0.69, 95% CI: 0.54~0.88),亚组分析结果显示,母亲孕期铁营养和子代CHD的关系稳定。此外,母亲孕期增补铁剂≥30 d子代在室间隔缺损(ventricular septal defect, VSD)、房间隔缺损(atrial septal defect, ASD)、动脉导管未闭(patent ductus arteriosus, PDA)、法洛四联症(tetralogy of fallot, TOF)上发生风险均降低,增补铁剂 < 30 d子代在ASD发生风险降低,孕期膳食铁摄入量较高(≥29 mg/d)子代在VSD、PDA发生风险均降低。  结论  母亲孕期铁营养水平升高降低了子代CHD的发生风险,孕妇孕期应注意机体铁营养的摄入和补充,促进母婴健康。     

Pregnancy outcomes, infant mortality, and arsenic in drinking water in West Bengal, India

Between 2001 and 2003, the authors studied pregnancy outcomes and infant mortality among 202 married women in West Bengal, India. Reproductive histories were ascertained using structured interviews. Arsenic exposure during each pregnancy, including all water sources used, was assessed; this involved measurements from 409 wells. Odds ratios for spontaneous abortion, stillbirth, neonatal mortality, and infant mortality were estimated with logistic regression based on the method of generalized estimating equations. Exposure to high concentrations of arsenic (> or =200 microg/liter) during pregnancy was associated with a sixfold increased risk of stillbirth after adjustment for potential confounders (odds ratio (OR) = 6.07, 95% confidence interval (CI): 1.54, 24.0; p = 0.01). Arsenic-related skin lesions were found in 12 women who had a substantially increased risk of stillbirth (OR = 13.1, 95% CI: 3.17, 54.0; p = 0.002). The odds ratio for neonatal death was 2.81 (95% CI: 0.73, 10.8). No association was found between arsenic exposure and spontaneous abortion (OR = 1.01, 95% CI: 0.38, 2.70) or overall infant mortality (OR = 1.33, 95% CI: 0.43, 4.04). This study adds to the limited evidence that exposure to high concentrations of arsenic during pregnancy increases the risk of stillbirth. However, there was no indication of the increased rates of spontaneous abortion and overall infant mortality that have been reported in some studies.     

Infant mortality and air pollution: modifying effect by social class

Studies link air pollution with increased mortality; however, information on infants is scarce and inconclusive. OBJECTIVE: We studied short-term PM10 exposure, relating to increased respiratory-related infant mortality, and estimated for poor living conditions. METHODS: A case-crossover approach modeled the relationship between infant mortality (1 month-1 year of age), and ambient PM10 levels on days before death in Ciudad Juarez, Mexico (1997-2001). Socioeconomic level (SES) of the deceased was defined by residence location. RESULTS: Overall air pollutants did not affect infant mortality (odds ratio [OR] = 1.02, 95% confidence interval [CI] = 0.94-1.11 for PM10, lag1) but low SES increased risk. Each 20 microg/m3 in PM10 (24-hour average, lag1, cumulative over 2 previous days) increased respiratory-related mortality (OR = 1.61, 95% CI = 0.97-2.66; OR = 2.56; 95% CI = 1.06-6.17, respectively). Ozone levels did not affect infant mortality for any SES. CONCLUSIONS: Worse living conditions among lower SES concurred with increased mortality.     

Association between seasonal influenza vaccination with pre- and postnatal outcomes

Objective

Influenza vaccination during pregnancy is known to prevent severe influenza illness but its effects on other outcomes and the extent to which its safety is affected by timing of vaccination, maternal race/ethnicity and the type of vaccine is less clear. Therefore, we examined this in a large retrospective cohort.

Randomized, double-blind, placebo-controlled trial of selenium supplements among HIV-infected pregnant women in Tanzania: effects on maternal and child outcomes

BACKGROUND: In observational studies, adequate selenium status has been associated with better pregnancy outcomes and slowed HIV disease progression. OBJECTIVE: We investigated the effects of daily selenium supplements on CD4 cell counts, viral load, pregnancy outcomes, and maternal and infant mortality among 913 HIV-infected pregnant women. DESIGN: In this randomized, double-blind, placebo-controlled trial, eligible women between 12 and 27 wk of gestation were given daily selenium (200 mug as selenomethionine) or placebo as supplements from recruitment until 6 mo after delivery. All women received prenatal iron, folic acid, and multivitamin supplements irrespective of experimental assignment. RESULTS: The selenium regimen had no significant effect on maternal CD4 cell counts or viral load. Selenium was marginally associated with a reduced risk of low birth weight [relative risk (RR) = 0.71; 95% CI: 0.49, 1.05; P = 0.09] and increased risk of fetal death (RR = 1.58; 95% CI = 0.95, 2.63; P = 0.08), but had no effect on risk of prematurity or small-for-gestational age birth. The regimen had no significant effect on maternal mortality (RR = 1.02; 95% CI = 0.51, 2.04; P = 0.96). There was no significant effect on neonatal or overall child mortality, but selenium reduced the risk of child mortality after 6 wk (RR = 0.43; 95% CI = 0.19, 0.99; P = 0.048). CONCLUSION: Among HIV-infected women from Dar es Salaam, Tanzania, selenium supplements given during and after pregnancy did not improve HIV disease progression or pregnancy outcomes, but may improve child survival. This trial was registered at clinicaltrials.gov as NCT00197561.     

Cigarette smoking during pregnancy in rural Nepal. Risk factors and effects of beta-carotene and vitamin A supplementation

OBJECTIVE: We examined risk factors of smoking and the association between smoking and pregnancy-related and 6-month infant mortality in rural Nepal, where 30% women reported smoking during pregnancy. DESIGN: Cross-sectional analysis of risk factors associated with smoking status and health consequences of smoking, using prospective data collected as part of a randomized community trial to examine the effect of maternal vitamin A or beta-carotene supplementation on maternal mortality. SETTING: Rural, southeastern plains of Nepal. SUBJECTS AND METHODS: A total of 17 767 women contributed at least one pregnancy during 3.5 y of the study. Data on cigarette or bidi (rolled tobacco) smoking were collected using a 7-day recall, twice during pregnancy. Associations between smoking status and maternal diet, morbidity profile, household socioeconomic status and serum concentration of retinol, carotenoids and tocopherols were examined. Further, relative risk (RR) and 95% confidence intervals (CI) were calculated to estimate supplement effects on pregnancy-related mortality, stratified by smoking status during pregnancy. RESULTS: Smokers were more likely to be older, illiterate and poor compared to nonsmokers. Fruit and vegetable consumption among smokers and nonsmokers did not vary. However, smokers were more likely to consume meat/fish/eggs and less likely to consume milk than nonsmokers. They were also more likely to report symptoms of vaginal bleeding, edema, severe headache and convulsions during pregnancy relative to nonsmokers. Mortality per 100,000 pregnancies appeared to be higher among smokers than nonsmokers in the placebo group (915 vs 584, RR=1.57, 95% CI: 0.80-3.08). beta-Carotene supplementation reduced pregnancy-related mortality both among smokers (RR=0.31 95% CI: 0.11-0.89) and nonsmokers (RR=0.41, 95% CI: 0.19-0.89). Similar results obtained with vitamin A supplementation were not statistically significant. Infant mortality up to 6 months was approximately 30% higher among smokers compared to nonsmokers in the placebo group both before and after adjusting for confounding factors. Neither supplement given to women reduced infant mortality. CONCLUSIONS: Cigarette smoking during pregnancy is associated with an increased risk of maternal and infant mortality in rural Nepal. beta-Carotene and to some extent vitamin A may reduce the risk of pregnancy-related mortality, but not infant mortality, among both smokers and nonsmokers.     

Perinatal mortality associated factors in a general hospital of Chiapas, Mexico

OBJECTIVE: To identify socioeconomic, gynecological-obstetric and fetal factors associated with perinatal mortality. METHODS: A matched case-control study was carried out. Cases were newborns (born live or dead) that were born and died between 28 weeks gestation and 7 days of life. Controls were live newborns between 28 weeks gestation and 7 days of life. A total of 99 cases and 197 controls were studied. Data were obtained from the corresponding medical charts. Statistical analysis was performed using Stata 6.0 software. RESULTS: Mean maternal age was 24.82 years and mean newborn age was 37.78 weeks gestation with an average birth weight of 2,760 grams. Factors associated with perinatal mortality were: father's occupation as a farmer (adjusted odds ratio (OR)=3.31; 95% CI=1.26-8.66); high obstetric risk index (adjusted OR=10.57; 95% CI=2.82-39.66), cesarean birth (adjusted OR=2.75; 95% CI=1.37-5.51), five or more prenatal visits (adjusted OR=4.43; 95% CI=1.86-10.54) and preterm fetal maturity indices (PEG, APG, GEG) (adjusted OR=9.20; 95% CI=4.39-19.25). CONCLUSIONS: The risk factors associated with perinatal mortality found in the study are consistent with the findings reported in the international literature. These results show that prevention and control measures should be implemented to identify at risk pregnant women in order to lower perinatal mortality.     

Parental occupational exposure to pesticides and childhood germ-cell tumors

In a recently completed US case-control study (Children's Oncology Group, 1993-2001) with 253 cases and 394 controls, the authors investigated the association between parental occupational exposure to pesticides and risk of childhood germ-cell tumors. Information on occupational pesticide exposure was collected using job-specific module questionnaires and assessed by an experienced industrial hygienist. Odds ratios for childhood germ-cell tumors associated with maternal exposures before pregnancy, during pregnancy, and after the birth of the index child were 1.0 (95% confidence interval (CI): 0.8, 1.4), 1.1 (95% CI: 0.7, 1.6), and 1.3 (95% CI: 0.9, 1.8), respectively. Paternal exposures before pregnancy, during pregnancy, and after the birth of the index child were not related to germ-cell tumors (odds ratios (ORs) were 0.9 (95% CI: 0.7, 1.2), 0.8 (95% CI: 0.5, 1.2), and 0.8 (95% CI: 0.5, 1.3), respectively). When both parents had ever been occupationally exposed to pesticides before the index pregnancy, the odds ratio was 0.8 (95% CI: 0.4, 1.3). Subgroup analyses showed a positive association between maternal exposure to herbicides during the postnatal period and risk of germ-cell tumors in girls (OR = 2.3, 95% CI: 1.0, 5.2) and an inverse association between paternal exposure to pesticides during the index pregnancy and germ-cell tumors in boys (OR = 0.2, 95% CI: 0.1, 1.0). This study did not provide strong evidence supporting a relation between parental pesticide exposure in the workplace and risk of germ-cell tumors among offspring.     

Maternal smoking and fetal growth characteristics in different periods of pregnancy: the generation R study

The authors examined the associations of maternal smoking in pregnancy with various fetal growth characteristics among 7,098 pregnant women participating in the Generation R Study (2002-2006), a population-based prospective cohort study of pregnant women and their children in Rotterdam, the Netherlands. Maternal smoking was assessed by questionnaires administered in early, mid-, and late pregnancy. Fetal growth characteristics evaluated included head circumference, abdominal circumference, and femur length measured repeatedly in mid- and late pregnancy. Maternal smoking during pregnancy was associated with reduced growth in head circumference (-0.56 mm/week; 95% confidence interval (CI): -0.73, -0.40), abdominal circumference (-0.58 mm/week; 95% CI: -0.81, -0.34), and femur length (-0.19 mm/week; 95% CI: -0.23, -0.14). This reduced growth resulted in a smaller femur length from midpregnancy (gestational age 18-24 weeks) onwards and smaller head and abdominal circumferences from late pregnancy (gestational age > or =25 weeks) onwards. Analyses using standard deviation scores for the growth characteristics demonstrated the largest effect estimates for femur length. The authors concluded that maternal smoking during pregnancy is associated with reduced growth in fetal head circumference, abdominal circumference, and femur length. The larger effect on femur length suggests that smoking during pregnancy affects primarily peripheral tissues.     

Decline in Child Marriage and Changes in Its Effect on Reproductive Outcomes in Bangladesh

This paper explores the decline in child marriage and changes in its effect on reproductive outcomes of Bangladeshi women, using the 2007 Bangladesh Demographic and Health Survey data. Chi-square tests, negative binomial Poisson regression and binary logistic regression were performed in analyzing the data. Overall, 82% of women aged 20-49 years were married-off before 18 years of age, and 63% of the marriages took place before 16 years of age. The incidence of child marriage was significantly less among the young women aged 20-24 years compared to their older counterparts. Among others, women''s education appeared as the most significant single determinant of child marriage as well as decline in child marriage. Findings revealed that, after being adjusted for sociodemographic factors, child marriage compared to adult marriage appeared to be significantly associated with lower age at first birth (OR=0.81, 95% CI=76-0.86), higher fertility (IRR=1.45, 95% WCI=1.35-1.55), increased risk of child mortality (IRR=1.64, 95% WCI=1.44-1.87), decreased risk of contraceptive-use before any childbirths (OR=0.56, 95% CI=0.50-0.63), higher risk of giving three or more childbirth (OR=3.94, 95% CI=3.38-4.58), elevated risk of unplanned pregnancies (OR=1.21, 95% CI=1.02-1.45), increased risk of pregnancy termination (OR=1.16, 95% CI=1.00-1.34), and higher risk of the use of any current contraceptive method (OR=1.20, 95% CI=1.06-1.35). Increased enforcement of existing policies is crucial for the prevention of child marriage. Special programmes should be undertaken to keep girls in school for longer period to raise the age of females at first marriage in Bangladesh and thereby reduce the adverse reproductive outcomes.Key words: Age at first birth, Child marriage, Child mortality, Induced abortion, Reproductive outcomes, Unintended pregnancy, Bangladesh     

Birth rates and reproductive risk in adolescents in Chile, 1990-1999]

OBJECTIVE: For Chilean teenage mothers under 15 years old and from 15 to 19 years old, to evaluate the trends in birth rates and reproductive risk for the period of 1990-1999. METHODS: A database was constructed using data from the Demography Yearbook (Anuario de demografía) volumes published by Chile's National Institute of Statistics (Instituto Nacional de Estadísticas) for 1990-1999. From that database we calculated the trends in the number of live births and in the rates of maternal mortality, late fetal mortality, neonatal mortality, and infant mortality among the teenage mothers under 15 and from 15 to 19 years old. We calculated the risk odds ratio (OR) for both of those age groups in comparison with women from 20 to 34 years old. The groups were compared using Fisher's exact test or the chi-square test, and the analysis of trends in the period studied was carried out with Pearson's correlation, with an alpha level of 0.05. RESULTS: In the period studied, for the teenage mothers under age 15, the respective rates for maternal mortality, late fetal mortality, neonatal mortality, and infant mortality were 41.9 per 100 000 live births, 5.1 per 1 000 live births, 15.2 per 1 000 live births, and 27.4 per 1 000 live births. For the adolescents from 15 to 19 years, the corresponding rates were 19.3, 4.1, 8.1, and 16.6; for the women 20-34 years old, they were 26.8, 5.0, 6.7, and 12.1. The adolescents under 15 had higher risks of maternal mortality (OR = 1.56; 95% confidence interval (CI): 0.50 to 4.31; P = 0.372) and of fetal mortality (OR = 1.02; 95% CI: 0.76 to 1.36; P = 0.890), but those differences were not statistically significant. However, the younger adolescents did have significantly higher risks of neonatal mortality (OR = 2.27; 95% CI: 1.92-2.68; P < 0.0001) and of infant mortality (OR = 2.39; 95% CI: 2.04 to 2.62; P < 0.0001). In comparison to the women 20-34 years old, the teenage mothers from 15 to 19 years old had significantly lower risks of maternal mortality (OR = 0.72; 95% CI: 0.56 to 0.92; P < 0.008) and of fetal mortality (OR = 0.81; 95% CI: 0.77 to 0.86; P < 0.0001) but significantly higher risks of neonatal mortality (OR = 1.20; 95% CI: 1.16 to 1.25; P < 0.0001) and of infant mortality (OR = 1.38; 95% CI: 1.35 to 1.42; P < 0.0001). Among both the older teenage mothers and the mothers 20-34 years old there was a significant downward trend in maternal, fetal, neonatal, and infant mortality rates in the period studied; in the younger adolescents only neonatal mortality and infant mortality declined significantly. There was a rising trend in the number of live births among the two groups of teenage mothers, but that trend was statistically significant only for the mothers under 15; among mothers 20-34 years old there was a statistically significant downward trend. CONCLUSIONS: In the period studied, the Chilean teenage mothers faced greater reproductive risk than did the women 20-34 years old. The number of live births among teenage mothers tended to rise during the 1990-1999 period, but the change was significant only for the mothers under age 15. These results point to the need to develop programs that improve both sex education and birth control practices starting in early adolescence.     

Risk of death following pregnancy in rural Nepal

OBJECTIVE: To investigate the length of time following pregnancy during which the risk of mortality was elevated among women in rural Nepal. METHODS: An analysis was performed of prospective data on women participating in the control group of a large, population-based trial. Weekly visits were made for three years to 14805 women aged 14-45 years. Pregnancy and vital status were assessed. A total of 7325 pregnancies were followed. Mortality during and following pregnancy, expressed on a person-time basis, was compared to referent mortality unrelated to pregnancy (52 weeks after pregnancy) in the same cohort. FINDINGS: The relative risk (RR) of death during pregnancy but before the onset of labour was 0.93 (95% confidence interval (CI): 0.38-2.32). During the perinatal period, defined as lasting from the onset of labour until seven days after outcome, the RR of death was 37.02 (95% CI: 15.03-90.92). The RR for 2 to 6 weeks, 7 to 12 weeks, and 13 to 52 weeks after pregnancy were 4.82, 2.59 and 1.01 with 95% CI of 1.77-13.07, 0.81-8.26 and 0.40-2.53, respectively. The RR of death was 2.21 (95% CI. 1.03-4.71) during the conventional maternal mortality period (pregnancy until 6 weeks after outcome). It was 2.26 (95% CI: 1.05-4.90) when the period was extended to 12 weeks after pregnancy outcome. CONCLUSION: The risk of mortality associated with pregnancy should be assessed over the first 12 weeks following outcome instead of over the first 6 weeks.     

Perinatal risk factors for infantile autism

BACKGROUND: Etiologic hypotheses in infantile autism suggest a strong genetic component, as well as possible environmental risks linked to early fetal development. We evaluated the association of maternal, pregnancy, delivery, and infant characteristics and risk of infantile autism. METHODS: We conducted a case-control study nested within a population-based cohort (all Swedish children born in 1974-1993). We used prospectively recorded data from the Swedish Birth Register, which were individually linked to the Swedish Inpatient Register. Cases were 408 children (321 boys and 87 girls) discharged with a main diagnosis of infantile autism from any hospital in Sweden before 10 years of age in the period 1987-1994, plus 2,040 matched controls. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: The risk of autism was associated with daily smoking in early pregnancy (OR = 1.4; CI = 1.1-1.8), maternal birth outside Europe and North America (OR = 3.0; CI = 1.7-5.2), cesarean delivery (OR = 1.6; CI = 1.1-2.3), being small for gestational age (SGA; OR = 2.1; CI = 1.1-3.9), a 5-minute Apgar score below 7 (OR = 3.2, CI = 1.2-8.2), and congenital malformations (OR = 1.8, CI = 1.1-3.1). No association was found between autism and head circumference, maternal diabetes, being a twin, or season of birth. CONCLUSIONS: Our findings suggest that intrauterine and neonatal factors related to deviant intrauterine growth or fetal distress are important in the pathogenesis of autism.     

Antecedents of macrosomia.

Antecedents of high birthweight (macrosomia) were studied using the state birth certificates of White singleton infants born in three large metropolitan counties of Washington State from 1984 to 1986. Cases consisted of 2082 live-born macrosomic infants, defined by a birthweight of over 4.5 kg. A random sample of 4440 live births with birthweights of 2.5-4.0 kg was selected as a comparison group. Estimates for the independent risks associated with gestational and established diabetes, male sex, parity, duration of gestation, maternal smoking during pregnancy, maternal age, and median income of maternal residential area were obtained and combined in a single logistic model. Maternal smoking was associated with a decreased risk of macrosomia (OR 0.4, 95% CI 0.3-0.5). Established diabetes (OR 6.4, 95% CI 2.7-15.4), gestational diabetes (OR 3.2, 95% CI 2.1-5.1) and male sex of the infant (OR 2.4, 95% CI 2.2-2.7) were associated with an increased risk. Increasing parity was related to an increasing risk from para one (OR 1.4, 95% 1.2-1.6) to para six and greater (OR 3.3, 95% CI 1.5-7.4). Increasing duration of gestation was associated with an increasing risk from 33-36 weeks (OR 0.8, 95% CI 0.5-1.2) to 43-45 weeks (OR 3.3, 95% CI 2.5-4.2). Maternal age, median income of maternal area of residence, and maternal marital status were not significantly associated with macrosomia.     

Antecedents of macrosomia

Summary. Antecedents of high birthweight (macrosomia) were studied using the state birth certificates of White singleton infants born in three large metropolitan counties of Washington State from 1984 to 1986. Cases consisted of 2082 live-born macrosomic infants, defined by a birthweight of over 4.5 kg. A random sample of 4440 live births with birthweights of 2.5-4.0kg was selected as a comparison group. Estimates for the independent risks associated with gestational and established diabetes, male sex, parity, duration of gestation, maternal smoking during pregnancy, maternal age, and median income of maternal residential area were obtained and combined in a single logistic model. Maternal smoking was associated with a decreased risk of macrosomia (OR 0.4, 95% CI 0.3-0.5). Established diabetes (OR 6.4, 95% CI 2.7–15.4), gestational diabetes (OR 3.2, 95% CI 2.1–5.1) and male sex of the infant (OR 2.4, 95% CI 2.2-2.7) were associated with an increased risk. Increasing parity was related to an increasing risk from para one (OR 1.4, 95% 1.2-1.6) to para six and greater (OR 3.3, 95% CI 1.5–7.4). Increasing duration of gestation was associated with an increasing risk from 33–36 weeks (OR 0.8, 95% CI 0.5-1.2) to 43–45 weeks (OR 3.3, 95% CI 2.5-4.2). Maternal age, median income of maternal area of residence, and maternal marital status were not significantly associated with macrosomia.     

Association between maternal exposure to ambient air pollutants during pregnancy and fetal growth restriction

Previous research demonstrated consistent associations between ambient air pollution and emergency room visits, hospitalizations, and mortality. Effect of air pollution on perinatal outcomes has recently drawn more attention. We examined the association between intrauterine growth restriction (IUGR) among singleton term live births and sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and fine particles (PM2.5) present in ambient air in the Canadian cities of Calgary, Edmonton, and Montreal for the period 1985-2000. Multiple logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for IUGR, based on average daily levels of individual pollutants over each month and trimester of pregnancy after adjustment for maternal age, parity, infant gender, season, and city of residence. A 1 ppm increase in CO was associated with an increased risk of IUGR in the first (OR=1.18; 95% CI 1.14-1.23), second (OR=1.15; 95% CI 1.10-1.19) and third (OR=1.19; 95% CI 1.14-1.24) trimesters of pregnancy, respectively. A 20 ppb increase in NO2 (OR=1.16; 95% CI 1.09-1.24; OR=1.14; 95% CI 1.06--1.21; and OR=1.16; 95% CI 1.09-1.24 in the first, second, and third trimesters) and a 10 mug/m3 increase in PM2.5 (OR=1.07; 95% CI 1.03-1.10; OR=1.06; 95% CI 1.03-1.10; and OR=1.06; 95% CI 1.03-1.10) were also associated with an increased risk of IUGR. Consistent results were found when ORs were calculated by month rather than trimester of pregnancy. Our findings add to the emerging body of evidence that exposure to relatively low levels of ambient air pollutants in urban areas during pregnancy is associated with adverse effects on fetal growth.     

Physical exposures during pregnancy and congenital cardiovascular malformations

Congenital cardiovascular malformations (CCM) cause substantial neonatal morbidity and mortality. Known risk factors for CCM explain only 10-20% of all cases. Few studies have examined mothers' physical exposures during pregnancy and the risk of CCM in their offspring. This study examined the association between exposures to extreme temperatures, prolonged standing, and heavy lifting during early pregnancy and risk of CCM in offspring. Using a case-control study design, 502 cases and 1066 controls were drawn from the population of all liveborn infants born between January 1988 and June 1991 to mothers living in 14 counties in New York State. Cases were identified from a population-based registry of congenital malformations. Controls were randomly selected from birth certificate records. Interviews were conducted by telephone, using a structured questionnaire. Exposure estimates were based on women's self-reports of conditions in the residence and workplace. Eighty-three per cent of the mothers were white, and 66% were between 25 and 34 years old. After adjusting all results for known risk factors and confounding variables, we found no significant increased risk of CCM in subjects whose mothers reported being exposed during early pregnancy to extreme heat (OR = 1.13, 95% CI 0.59, 2.19), nor to extreme cold (OR = 1.19, 95% CI 0.66, 2.15). Mothers who reported ever using a hot tub, hot bath, or sauna during early pregnancy had no increased risk of CCM in their offspring (OR = 0.88, 95% CI 0.65, 1.18). Performing heavy lifting during early pregnancy did not increase the risk of CCM in offspring (OR = 0.80, 95% CI 0.57, 1.11). Prolonged standing during early pregnancy was not associated with an increased risk of CCM in children (OR = 1.03, 95% CI 0.82, 1.28). Thus if these maternal exposures have an adverse effect, it is unlikely to involve CCMs.     

隐睾发生的危险因素研究

目的：研究隐睾发生的危险因素。方法：采用以医院为基础的1：2配比的病例对照研究方法，按统一的调查方法对99例隐睾及198例对照组面对面问卷调查。应用SAS6。12软件对所调查因素进行单因素及多因素logistic回归分析，结果：胎儿隐睾与母亲孕早期感冒伴发热（OR＝9．37，95％CI：2．25－39．09），孕期发生先兆流产（OR＝4．66，95％CI，2．02＝10．74），孕期发生先兆子痫（OR＝16．33，95％CI：1．40－191．20），父亲职业性接触农药（OR＝12．79％CI；2．90－56．43），低出生体重（OR＝5．77，95％CI：1．39－23．98），母亲怀孕年龄＜24（OR＝2．89，95％CI：1．29－4．06）呈正相关。结论：母亲孕早期感冒伴发热，孕期发生先兆流产及先兆子痫，父亲职业性接触农药，低出体重，母亲怀孕年龄＜24岁是隐睾发病的主要危险因素。