The influence of age at exposure to PBBs on birth outcomes

The determination of critical windows of susceptibility to environmental chemical exposures and health has become a major public health focus. This study examined the association between early age at exposure to polybrominated biphenyls (PBBs) and subsequent birth weight and gestational length in offspring among females. The study population consisted of 1111 births that occurred among 560 women enrolled in the Michigan PBB Cohort from 1975 to 1994. Maternal age at exposure was categorized into three groups:<10 years (n = 64), 11-16 years (n = 149), and 17-42 years (n = 347). Overall serum PBB levels ranged from 0 to 1490 ppb, with a median of 2, 3, and 2 ppb in the three age groups, respectively. Separate mixed-effects linear regression models were used to evaluate the effect of age at exposure (years) and initial PBB level (ppb) on birth weight (grams) and gestational age (weeks), controlling for gestational age (weeks) (in the model examining effects on birth weight), BMI (kg/m(2)) and serum PCB level at enrollment (ppb), maternal age and paternal education at delivery, parity, infant gender, interval between the initial serum test and date of delivery (years), and the trimester in which prenatal care was initiated. Relative to the oldest age group, age<10 years at exposure was the most important predictor of increased birth weight (estimated regression coefficient = 225 g, P = 0.012). Infant birth weight increased approximately 16 g for every 10 ppb increase in serum PBBs (P=0.004). There was no association between initial PBB levels and gestational age, nor were initial serum PCB levels associated with either infant birth weight or gestational length. These results provide support for the hypothesis that early age at exposure may be an important determinant in subsequent health effects due to environmental chemical exposures.     

Prenatal lead exposure and weight of 0- to 5-year-old children in Mexico city

Background: Cumulative prenatal lead exposure, as measured by maternal bone lead burden, has been associated with smaller weight of offspring at birth and 1 month of age, but no study has examined whether this effect persists into early childhood.Objective: We investigated the association of perinatal maternal bone lead, a biomarker of cumulative prenatal lead exposure, with children’s attained weight over time from birth to 5 years of age.Methods: Children were weighed at birth and at several intervals up until 60 months. Maternal tibia and patella lead were measured at 1 month postpartum using in vivo K-shell X-ray fluorescence. We used varying coefficient models with random effects to assess the association of maternal bone lead with weight trajectories of 522 boys and 477 girls born between 1994 and 2005 in Mexico City.Results: After controlling for breast-feeding duration, maternal anthropometry, and sociodemographic characteristics, a 1-SD increase in maternal patella lead (micrograms per gram) was associated with a 130.9-g decrease in weight [95% confidence interval (CI), –227.4 to –34.4 g] among females and a 13.0-g nonsignificant increase in weight among males (95% CI, –73.7 to 99.9 g) at 5 years of age. These associations were similar after controlling for concurrent blood lead levels between birth and 5 years.Conclusions: Maternal bone lead was associated with lower weight over time among female but not male children up to 5 years of age. Given that the association was evident for patellar but not tibial lead levels, and was limited to females, results need to be confirmed in other studies.     

Prenatal exposure to tetrachloroethylene-contaminated drinking water and the risk of adverse birth outcomes

BACKGROUND: Prior studies of prenatal exposure to tetrachloroethylene (PCE) have shown mixed results regarding its effect on birth weight and gestational age. OBJECTIVES: In this retrospective cohort study we examined whether PCE contamination of public drinking-water supplies in Massachusetts influenced the birth weight and gestational duration of children whose mothers were exposed before the child's delivery. METHODS: The study included 1,353 children whose mothers were exposed to PCE-contaminated drinking water and a comparable group of 772 children of unexposed mothers. Birth records were used to identify subjects and provide information on the outcomes. Mothers completed a questionnaire to gather information on residential histories and confounding variables. PCE exposure was estimated using EPANET water distribution system modeling software that incorporated a fate and transport model. RESULTS: We found no meaningful associations between PCE exposure and birth weight or gestational duration. Compared with children whose mothers were unexposed during the year of the last menstrual period (LMP), adjusted mean differences in birth weight were 20.9, 6.2, 30.1, and 15.2 g for children whose mothers' average monthly exposure during the LMP year ranged from the lowest to highest quartile. Similarly, compared with unexposed children, adjusted mean differences in gestational age were -0.2, 0.1, -0.1, and -0.2 weeks for children whose mothers' average monthly exposure ranged from the lowest to highest quartile. Similar results were observed for two other measures of prenatal exposure. CONCLUSIONS: These results suggest that prenatal PCE exposure does not have an adverse effect on these birth outcomes at the exposure levels experienced by this population.     

Prenatal care utilization: its measurement and relationship to pregnancy outcome

This study proposes a redesigned measure of prenatal care utilization based on modifications made to a preexisting index of the adequacy of such care. Six prenatal care utilization groups were delineated: intensive, adequate, intermediate, inadequate, no-care, and missing/unknown. Using 430,349 cases from South Carolina and North Carolina vital records from 1978 to 1982 (live birth-infant death cohort files for white resident mothers), this proposed prenatal care utilization measure was examined by maternal sociomedical risk characteristics (age-parity, marital status, education, complications of pregnancy, and previous pregnancy terminations) and by pregnancy outcomes (birth weight, gestational age, and birth weight- and gestational age-specific neonatal mortality). The intensive prenatal care group had relatively more pregnancy complications but also the most preferred pregnancy outcomes. Appreciable differences in birth weight and gestational age distributions were observed among the prenatal care categories within maternal risk status groups. Increased utilization of prenatal care was associated with higher mean birth weight and gestational age. However, after controlling for maternal risk status, an appreciable variation in birth weight- and gestational age-specific neonatal mortality was not apparent across prenatal care groups.     

Exploring Birth Outcome Disparities and the Impact of Prenatal Care Utilization Among North Carolina Teen Mothers

BackgroundThis study investigated the role of prenatal care utilization in explaining disparities in birth outcomes between African-American and White teen mothers in North Carolina.MethodsThis cross-sectional study analyzed birth record data for African-American and White teen mothers provided by the North Carolina State Center of Health Statistics for 2009 (n = 10,515). Hierarchical moderated multiple regression models were completed to explore associations between racial status, prenatal care utilization, and birth outcome disparities amid multiple demographic and medical risk factors.FindingsRacial status as African American was identified as a significant predictor for lower birth weight and gestational age in each regression model when accounting for other demographic variables, medical risk factors, and prenatal care utilization. Results illuminate significant associations between higher prenatal care utilization levels and higher infant birth weight and gestational age for the overall teen population. However, these results did not identify protective effects in reducing racial disparities in birth weight or gestational age.ConclusionGiven these results, a more in-depth exploration of prenatal care client assessment, education, and alternative prenatal care models is warranted to identify strategies for reducing birth outcome disparities between these populations. These findings also suggest the need for further examination of other potential social and economic factors that explain racial disparities in birth outcomes between African-American and White teen populations.     

Indicators of Acculturation Related to Somali Refugee Women’s Birth Outcomes in Minnesota

We investigated the effect of indicators of acculturation among Somali refugee women’s birth outcomes. Data were extracted from medical records of 584 Somali women delivering infants at a Midwestern hospital between 1993 and 2006. Bivariate analyses measured relationships between independent factors and the dependent variables of gestational age and birthweight. Structural equation modeling (SEM) determined the fit between factors hypothesized to reflect acculturation and the data. Significant increases noted over time were substance use/exposure, interpreter use, body mass index, hemoglobin levels, gestational diabetes and preterm birth. Bivariate analyses showed significance between prenatal care utilization and both preterm birth and gestational age. SEM results indicated a moderate to good fit between the hypothesized model and available data. Factors hypothesized to reflect acculturation and effect birth outcomes among Somali women are increasing but did not account for increased preterm birth. Further investigation is warranted to identify and truncate further disparate birth outcomes.     

Associations between combined exposure to environmental hazards and social stressors at the neighborhood level and individual perinatal outcomes in the ECHO-wide cohort

Limited studies examine how prenatal environmental and social exposures jointly impact perinatal health. Here we investigated relationships between a neighborhood-level combined exposure (CE) index assessed during pregnancy and perinatal outcomes, including birthweight, gestational age, and preterm birth. Across all participants, higher CE index scores were associated with small decreases in birthweight and gestational age. We also observed effect modification by race; infants born to Black pregnant people had a greater risk of preterm birth for higher CE values compared to White infants. Overall, our results suggest that neighborhood social and environmental exposures have a small but measurable joint effect on neonatal indicators of health.     

Gender differences in fetal growth of newborns exposed prenatally to airborne fine particulate matter

Our primary purpose was to assess sex-specific fetal growth reduction in newborns exposed prenatally to fine particulate matter. Only women 18-35 years of age, who claimed to be non-smokers, with singleton pregnancies, without illicit drug use and HIV infection, free from chronic diseases were eligible for the study. A total of 481 enrolled pregnant women who gave birth between 37 and 43 weeks of gestation were included in the study. Prenatal personal exposure to fine particles over 48 h during the second trimester was measured using personal monitors. To evaluate the relationship between the level of PM_2.5 measured over 48 h in the second trimester of pregnancy with those in the first and the third trimesters, a series of repeated measurements in each trimester was carried out in a random subsample of 85 pregnant women. We assessed the effect of PM_2.5 exposure on the birth outcomes (weight, length and head circumference at birth) by multivariable regression models, controlling for potential confounders (maternal education, gestational age, parity, maternal height and prepregnancy weight, sex of infant, prenatal environmental tobacco smoke, and season of birth). Birth outcomes were associated positively with gestational age, parity, maternal height and prepregnancy weight, but negatively with the level of prenatal PM_2.5 exposure. Overall average increase in gestational period of prenatal exposure to fine particles by about 30 μg/m³, i.e., from 25th percentile (23.4 μg/m³) to 75th percentile (53.1 μg/m³) brought about an average birth weight deficit of 97.2 g (95% CI: −201, 6.6) and length at birth of 0.7 cm (95% CI: −1.36, −0.04). The corresponding exposure lead to birth weight deficit in male newborns of 189 g (95% CI: −34.2, −343) in comparison to 17 g in female newborns; the deficit of length at birth in male infants amounted to 1.1 cm (95% CI: −0.11, −2.04). We found a significant interrelationship between self-reported ETS and PM_2.5, however, none of the models showed a significant interaction of both variables. The joint effect of various levels of PM_2.5 and ETS on birth outcomes showed the significant deficit only for the categories of exposure with higher component of PM_2.5. Concluding, the results of the study suggest that observed deficits in birth outcomes are rather attributable to prenatal PM_2.5 exposure and not to environmental tobacco smoke. The study also provided evidence that male fetuses are more sensitive to prenatal PM_2.5 exposure and this should persuade policy makers to consider birth outcomes by gender separately while setting air pollution guidelines.     

Fetal exposure to lead during pregnancy and the risk of preterm and early-term deliveries

Studies have reported the association between lead exposure during pregnancy and preterm birth. However, findings are still inconsistent. This prospective birth cohort study evaluated the risks of preterm and early-term births and its association with prenatal lead exposure in Hubei, China. A total of 7299 pregnant women were selected from the Healthy Baby Cohort. Maternal urinary lead levels were measured by the Inductively Coupled Plasma Mass Spectrometry. The associations between tertiles of urinary lead levels and the risks of preterm and early-term deliveries were assessed using multiple logistic regression models. The geometric mean of creatinine-adjusted urinary lead concentrations among all participating mothers, preterm birth, and early-term birth were 3.19, 3.68, and 3.17 µg/g creatinine, respectively. A significant increase in the risk of preterm births was associated with the highest urinary lead tertile after adjusting for confounders with odds ratio (OR) of 1.96. The association was more pronounced among 25–36 years old mothers with OR of 2.03. Though significant p trends were observed between lead exposure (medium and high tertiles) and the risk of early-term births, their ORs were not significant. Our findings indicate that the risk of preterm birth might increase with higher fetal lead exposure, particularly among women between the age of 25 and 36 years.     

Weight gain and maturity in fetuses exposed to low levels of lead

The relationship between prenatal low-level lead exposure and fetal growth was evaluated in a sample of 4354 pregnancies in which the mean umbilical cord blood lead level was 7.0 micrograms/dl (SD = 3.3; 10th percentile, 3.4 micrograms/dl, 90th percentile, 10.9 micrograms/dl). Higher cord blood lead levels were significantly associated with gestations of slightly longer duration. Comparing infants with cord blood lead levels greater than or equal to 15 micrograms/dl to those with levels less than 5 micrograms/dl, adjusted risk ratios of 1.5 to 2.5 were observed for low birth weight (less than 2500 g) and for fetal growth indices that express birth weight as a function of length of gestation (e.g., small-for-gestational age, intrauterine growth retardation). The 95% confidence intervals of these risk ratios included 1, however, precluding rejection of the null hypothesis of no association. We conclude that the risk of adverse fetal growth is not increased at cord blood lead levels less than 15 micrograms/dl but that modest increases in risk may be associated with levels greater than or equal to 15 micrograms/dl.     

Environmental lead level and pregnancy-induced hypertension

Previous studies have suggested that environmental lead exposure increases the risk of hypertension in the general population. In this article, the authors used the 1998 linked birth/infant death database of the United States to examine the association between environmental lead level and the occurrence of pregnancy-induced hypertension (PIH). Yearly summaries of environmental lead levels were abstracted from the US Environmental Protection Agency's air pollution databases, and linked with birth/infant death records by state codes. Generalized estimating equations (GEEs) were used to evaluate the odds ratios of PIH associated with environmental lead measured at ecological levels, with adjustment for maternal age, race, education level, marital status, parity, and adequacy of prenatal care measured at individual levels, stratified by maternal cigarette smoking. A total of 2,994,072 women pregnant in 1998 were included in this study. With the first quartile of lead level as the reference group, the odds ratio for PIH among all study subjects in the second quartile of seasonal average lead level at conception was 1.07 (95% CI: 1.05-1.08), and odds ratios in the third and fourth quartiles were 1.22 (95% CI: 1.20-1.25) and 1.16 (95% CI: 1.15-1.18), respectively. The odds ratios for the second, third, and fourth quartiles of seasonal average lead level at birth were 1.07 (95% CI: 1.05-1.09), 1.21 (95% CI: 1.19-1.23), and 1.15 (95% CI: 1.13-1.17), respectively. The risk of PIH increased by 4% per 0.05 μg/m³ increase in seasonal average lead level at conception and birth, in both smokers and nonsmokers. These results suggest that higher environmental lead levels increase the risk of PIH.     

The relationship between assessed obstetric risk and maternal-perinatal outcome

The relationship between antepartum risk assessment and subsequent maternal and perinatal outcome was examined in a retrospective study of 430 randomly selected deliveries at the Oregon Health Sciences University during the 1986 calendar year. Antepartum risk scores at the initial prenatal visit and at 37 weeks' gestation were positively correlated with each other. Antepartum risk scores were correlated with maternal length of stay and maternal hospital charges, but not with gestational age, birth weight, or Apgar scores. Increased intrapartum risk scores were strongly correlated with increasing length of stay for mother and baby, lower birth weight, and lower estimated gestational age at birth. The ability of the risk-scoring system to predict selected adverse outcomes was then assessed using a high-risk cutoff score of 5 or greater. Sensitivity and positive predictive value were found to be quite low while specificity and negative predictive value were reasonably high. The results suggest that the risk-scoring system used at this institution is effective in identifying low obstetrical risk and that prenatal care reduces the probability of poor neonatal outcome among infants of women at high obstetrical risk identified through antepartum multivariate assessment. Two antepartum risk assessments, each measuring different factors, may be redundant. Not yet known are which specific factors by their identification result in more effective prenatal care.     

Parental exposure to lead and small for gestational age births

BACKGROUND: Previous studies about the effect of lead exposure on adverse birth outcomes are still inconsistent and few studies estimate the relationship between parental lead exposure and small for gestational age (SGA) infants. An occupational cohort study to assess whether parental lead exposure would be related to decreased birth weight and shortened gestational ages of their offspring was conducted. Whether higher lead exposure doses would increase risks of low birth weight (LBW), preterm delivery, and SGA births was also investigated. METHODS: A Program to Reduce Exposure by Surveillance System-Blood Lead Levels (Press-BLLS) was established in Taiwan in July 1993. The names of workers exposed to lead was collected from this occupational blood-lead notification database. The birth outcomes of their offspring were determined by linking to the Taiwan birth registration database from 1993 to 1997. Only singleton births whose parental blood-lead concentrations were tested during pregnancy or prior to conception, or within a 1-year span before these two periods were included. RESULTS: Among 1,611 eligible births, 72 births were LBW, 74 were preterm deliveries, and 135 were SGA. Maternal blood-lead concentrations (PbBs) equal to or more than 20 microg/dl had a higher risk of mothering a SGA child (risk ratio (RR) = 2.15; 95% confidence interval (CI), 1.15-3.83). CONCLUSIONS: Additional evidence of the effects of lead on adverse birth outcomes, especially for SGA births is reported. Maternal exposure to lead plays a more important role in the adverse effect on birth outcome than does paternal exposure.     

Very low maternal lead level in pregnancy and birth outcomes in an eastern Massachusetts population

PurposeMaternal lead exposure is associated with poor birth outcomes in populations with moderate to high blood levels. However, no studies have looked at exposure levels commonly experienced by US women.MethodsWe evaluated the relationship between maternal red blood cell (RBC) lead levels in midpregnancy and birth outcomes in 949 mother–child pairs in a prebirth cohort. We used multiple linear regression and logistic regression, adjusted for potential confounders including maternal age, race, prepregnancy body mass index, and smoking to relate maternal lead to infant birth size and risk for preterm birth (<37 weeks).ResultsMean RBC lead level was 1.2 μg/dL (range, 0.0–5.0). Mean (standard deviation) birthweight was 3505 (520) g, birthweight for gestational age z-score 0.22 (0.93), and length of gestation 39.5 (1.7) weeks. Mothers in the highest versus lowest lead quartile did not have higher odds (OR, 1.85; 95% confidence interval [CI], 0.79–4.34) of preterm delivery; after stratifying by child sex, there was an association among males (OR, 5.51; 95% CI, 1.21–25.15) but not females (OR, 0.82; 95% CI, 0.24–2.85). Maternal RBC lead was not associated with any continuous outcomes in combined or sex-stratified analyses.ConclusionsMaternal lead exposure, even at very low levels, may adversely affect some childbirth outcomes, particularly preterm birth among males.     

Total Trihalomethanes in Public Drinking Water Supply and Birth Outcomes: A Cross-Sectional Study

Reproductive effects of long-term, low-dose exposure to disinfectant by-products have not been consistently documented in large populations despite the known toxicity of high exposures and the wide-spread occurrence of low concentrations in public drinking water. We investigated the effect of low-dose exposure to total trihalomethanes (TTHM) on birth weight and gestational term in New York State. All singleton live births from 1998 through 2003 in 62 counties in New York State were linked with public water supply (PWS) system boundaries based on mother’s residential address on birth certificate. Using the data from public water supply system, TTHM measurements were assigned geographically and temporally to each birth record linked with PWS boundary. Individual level maternal information including mother’s race, ethnicity, education, employment status, smoking, age, along with adequacy of prenatal care utilization and infant’s gender was used in a logistic model to adjust for potential confounding. A small non-linear association was detected between TTHM exposure and low birth weight (<2,500 g) births (OR 1.14; 95 % confidence interval (CI) 1.08–1.21), preterm births (OR 1.14; 95 % CI 1.08–1.20) and for small for gestational age births (OR 1.10; 95 % CI 1.04–1.16) suggesting a small increase in risk for these birth outcomes with chronic low maternal exposure to drinking water containing trihalomethanes. Maternal exposure to TTHMs during pregnancy may be associated with low birth weight, preterm births and small for gestational age births.     

Ambient air pollution and low birth weight in Connecticut and Massachusetts

BACKGROUND: Several studies have examined whether air pollution affects birth weight; however results vary and many studies were focused on Southern California or were conducted outside of the United States. OBJECTIVES: We investigated maternal exposure to particulate matter with aerodynamic diameter < 10, < 2.5 microm (PM(10), PM(2.5)), sulfur dioxide, nitrogen dioxide, and carbon monoxide and birth weight for 358,504 births in Massachusetts and Connecticut from 1999 to 2002. METHODS: Analysis included logistic models for low birth weight (< 2,500 g) and linear models with birth weight as a continuous variable. Exposure was assigned as the average county-level concentration over gestation and each trimester based on mother's residence. We adjusted for gestational length, prenatal care, type of delivery, child's sex, birth order, weather, year, and mother's race, education, marital status, age, and tobacco use. RESULTS: An interquartile increase in gestational exposure to NO(2), CO, PM(10), and PM(2.5) lowered birth weight by 8.9 g [95% confidence interval (CI), 7.0-10.8], 16.2 g (95% CI, 12.6-19.7), 8.2 g (95% CI, 5.3-11.1), and 14.7 g (95% CI, 12.3-17.1), respectively. Lower birth weight was associated with exposure in the third trimester for PM(10), the first and third trimesters for CO, the first trimester for NO(2) and SO(2), and the second and third trimesters for PM(2.5). Effect estimates for PM(2.5) were higher for infants of black mothers than those of white mothers. CONCLUSIONS: Results indicate that exposure to air pollution, even at low levels, may increase risk of low birth weight, particularly for some segments of the population.     

Prenatal exposure to methylmercury and LCPUFA in relation to birth weight

BackgroundEpidemiologic studies have been inconclusive regarding the impact of coexposure to long chain polyunsaturated fatty acids (LCPUFA) and methylmercury (MeHg) from fish consumption during pregnancy on measures of fetal development.ObjectivesWe evaluated the association between birth weight and prenatal maternal LCPUFA status and MeHg exposure in the Republic of Seychelles.MethodsWe measured LCPUFA in maternal whole blood collected at 28 weeks of gestation and following delivery and MeHg in maternal hair obtained at delivery. There were 230 births with complete data on birth weight and covariates. Multiple linear regression models controlled for infant sex, gestational age, maternal age, smoking during pregnancy, intrapartum weight gain, prepregnancy body mass index, maternal socioeconomic status, parity, gestational diabetes, and alcohol use during pregnancy.ResultsThe average birth weight was 3252 g (range 1654–4450) and the average gestational age was 39 weeks (range 34–41). Prenatal MeHg exposure and maternal LCPUFA status were not associated with birth weight. Infant sex and length of gestation were the only predictors, with male sex and increased gestational age consistently associated with greater birth weight.ConclusionsThese findings do not support a relationship between prenatal exposure to LCPUFA and/or MeHg from fish consumption and birth weight.     

Prenatal exposure to airborne polycyclic aromatic hydrocarbons and risk of intrauterine growth restriction

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous air pollutants generated by combustion of organic material, including fossil fuel. OBJECTIVES: It has been an open question whether prenatal exposure to air pollution in general and PAHs in particular significantly increases the risk of intrauterine growth restriction, including small size for gestational age (SGA), and preterm delivery. Here, we have examined this hypothesis in a cohort of mothers and newborns in New York City. METHODS: Subjects were young, nonsmoking, healthy African-American (n = 224) and Dominican (n = 392) mother-newborn pairs residing in New York City whose prenatal PAH exposures were estimated by personal air monitoring. Questionnaire and medical record data were obtained. RESULTS: A 1 natural-log (ln)-unit increase in prenatal PAH exposure was associated with a 2-fold increase in risk of symmetric intrauterine growth restriction (i.e., SGA and fetal growth ratio < 85%) among full-term African Americans (p < 0.05). Preterm delivery risk was 5-fold greater among African Americans per ln-unit increase in prenatal PAH exposure. The same unit increase in exposure significantly increased the ratio of head circumference to birth weight by 0.04% in African Americans. These effects were not observed in Dominicans. CONCLUSION: Prenatal PAH exposure is likely to contribute to the occurrence of SGA as well as preterm births among African Americans. The lack of an association in Dominicans might reflect modification of the risk by healthful cultural practices among recent Dominican immigrants. Given that PAHs are globally generated and distributed pollutants, our observations have potential implications for environmental health and energy policies.     

The epidemiology of sudden infant death in upstate New York: II: birth characteristics.

This study describes the epidemiology of sudden infant death syndrome (SIDS) among infants born during 1974 to upstate New York residents. Birth certificate characteristics for 184 SIDS cases are compared with those of 417 infants dying from other causes in the same age range, 7-365 days. The results confirm the following as infant risk factors: fall or winter birth, low birthweight for gestational age, twin birth, and live birth order three or more. Maternal risk factors include: age under 20, abnormal uterine bleeding during pregnancy, late initiation of prenatal care, less than 12 years of education and single marital status. The increased risk for mothers who first gave birth in their teens and for second-born twins has not been previously reported. The evidence that SIDS babies are small for gestational age, that twins, especially the second born, and babies whose mothers experienced abnormal uterine bleeding during pregnancy are all at increased risk of SIDS suggests that perinatal stress leading to hypoxia is one of the components that determine the risk of SIDS.     

Impact of barbecued meat consumed in pregnancy on birth outcomes accounting for personal prenatal exposure to airborne polycyclic aromatic hydrocarbons: Birth cohort study in Poland

ObjectiveWe previously reported an association between prenatal exposure to airborne polycyclic aromatic hydrocarbons (PAH) and lower birth weight, birth length, and head circumference. The main goal of the present analysis was to assess the possible impact of coexposure to PAH-containing barbecued meat consumed during pregnancy on birth outcomes.Materials and methodsThe birth cohort consisted of 432 pregnant women who gave birth at term (>36 wk of gestation). Only non-smoking women with singleton pregnancies, 18–35 y of age, and who were free from chronic diseases such as diabetes and hypertension, were included in the study. Detailed information on diet over pregnancy was collected through interviews and the measurement of exposure to airborne PAHs was carried out by personal air monitoring during the second trimester of pregnancy. The effect of barbecued meat consumption on birth outcomes (birth weight, length, and head circumference at birth) was adjusted in multiple linear regression models for potential confounding factors such as prenatal exposure to airborne PAHs, child's sex, gestational age, parity, size of mother (maternal prepregnancy weight, weight gain in pregnancy), and prenatal environmental tobacco smoke.ResultsThe multivariable regression model showed a significant deficit in birth weight associated with barbecued meat consumption in pregnancy (coeff = ?106.0 g; 95%CI: ?293.3, ?35.8). The effect of exposure to airborne PAHs was about the same magnitude order (coeff. = ?164.6 g; 95%CI: ?172.3, ?34.7). Combined effect of both sources of exposure amounted to birth weight deficit of 214.3 g (95%CI: ?419.0, ?9.6). Regression models performed for birth length and head circumference showed similar trends but the estimated effects were of borderline significance level. As the intake of barbecued meat did not affect the duration of pregnancy, the reduced birth weight could not have been mediated by a shortened gestation period.ConclusionIn conclusion, the study results provided epidemiologic evidence that prenatal PAH exposure from diet including grilled meat might be hazardous for fetal development.