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.     

Chemical hair treatments and adverse pregnancy outcome among Black women in central North Carolina

Several studies suggest that toxic chemicals in hair products may be absorbed through the scalp in sufficient amounts to increase the risks of adverse health effects in women or their infants. This case-control study of 525 Black women from three counties in North Carolina who had delivered a singleton, liveborn infant examined whether exposure to chemicals used in hair straightening and curling increased the odds that the infant was preterm or low birth weight. Cases consisted of 188 preterm and 156 low birth weight births (for 123 women, their infant was both low birth weight and preterm). Controls were 304 women who delivered term and normal birth weight infants. Women who used a chemical hair straightener at any time during pregnancy or within 3 months prior to conception had an adjusted odds ratios (OR) of 0.7 (95% confidence interval (CI) 0.4-1.1) for preterm birth and 0.6 (95% CI 0.4-1.1) for low birth weight. Exposure to chemical curl products was also not associated with preterm delivery (adjusted OR = 0.9, 95% CI 0.5-1.8) or low birth weight (adjusted OR = 1.0, 95% CI 0.5-1.9). Despite this failure to find an association, continued search for risk factors to which Black women are uniquely exposed is warranted.     

Adverse birth outcomes associated with open dumpsites in Alaska Native Villages

This retrospective cohort study evaluated adverse birth outcomes in infants whose birth records indicated maternal residence in villages containing dumpsites potentially hazardous to health and environment. Birth records from 1997 to 2001 identified 10,073 eligible infants born to mothers in 197 Alaska Native villages. Outcomes included low or very low birth weight, preterm birth, and intrauterine growth retardation. Infants from mothers in villages with intermediate (odds ratio (OR) = 1.73, 95% confidence interval (CI): 1.06, 2.84) and high (OR = 2.06, 95% CI: 1.28, 3.32) hazard dumpsites had a higher proportion of low birth weight infants than did infants from mothers in the referent category. More infants born to mothers from intermediate (OR = 4.38, 95% CI: 2.20, 8.77) and high (OR = 3.98, 95% CI: 1.93, 8.21) hazard villages suffered from intrauterine growth retardation. On average, infants weighed 36 g less (95% CI: -71.2, -0.8) and 55.4 g less (95% CI: -95.3, -15.6) when born to highly exposed mothers than did infants in the intermediate and low exposure groups, respectively, an effect even larger in births to Alaska Native mothers only. No differences in incidence were detected across exposure levels for other outcomes. This is the first study to evaluate adverse pregnancy outcomes associated with open dumpsites in Alaska Native villages.     

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.     

Early short-term infant food supplementation, maternal weight loss and duration of breast-feeding: a randomised controlled trial in rural Senegal

OBJECTIVE: Early supplementation of breastfed infants may have consequences both for the mother and the child. We hypothesised that it would result in decreased maternal weight loss and in shorter durations of breastfeeding and birth intervals. DESIGN: Controlled randomised population-based trial. SETTING: Six villages in the Sine area of Senegal, West Africa.Subjects:Healthy breastfed infants and their mothers, 68 controls and 66 supplemented infants at randomization. INTERVENTION: Supplementation with high-energy, nutrient dense food from 4 to 7 months of age, twice daily under supervision of field workers. Both controls and supplemented infants were free to eat other complementary foods. Maternal weight was measured monthly. Dates of breastfeeding cessation and of subsequent births were collected prospectively through weekly demographic surveillance, and were analysed using Cox's regression models and 'intent-to-supplement' approach. RESULTS: Mean maternal weight gain from 4 to 7 months postpartum tended to be greater in the supplemented group (+0.25 kg/months, 95% confidence interval (CI): -0.07, +0.57). Supplemented infants were breastfed for significantly longer durations than controls (medians: 24.9 and 23.7 months, respectively, P: 0.034). Their adjusted hazard ratio (HR) for breastfeeding cessation was 0.59 (95% CI: 0.40, 0.89). Their mothers had a lower risk of a new birth than mothers of controls (adjusted HR: 0.57, 95% CI: 0.36, 0.92). CONCLUSIONS: Early short-term infant supplementation tended to decrease maternal postpartum weight loss, but it increased, rather than shortened, the duration of breastfeeding and birth interval. SPONSORSHIP: This study was supported by a grant from the French Ministry of Research (Grant 92L0623).     

Maternal obesity and infant heart defects

OBJECTIVE: This study determined whether obese women have an increased risk of cardiovascular defects in their offspring compared with average weight women. RESEARCH METHODS AND PROCEDURES: In a case-control study, prospectively collected information was obtained from Swedish medical health registers. The study included 6,801 women who had infants with a cardiovascular defect and, as controls, all delivered women (N = 812,457) during the study period (1992 to 2001). Infants with chromosomal anomalies or whose mothers had pre-existing diabetes were excluded. Obesity was defined as BMI >29 kg/m(2), and morbid obesity was defined as BMI >35 kg/m(2). Comparisons were made with average weight women (BMI = 19.8 to 26 kg/m(2)). RESULTS: In the group of obese mothers, there was an increased risk for cardiovascular defects compared with the average weight mothers [adjusted odds ratio (OR) = 1.18; 95% CI, 1.09 to 1.27], which was slightly more pronounced for the severe types of cardiovascular defects (adjusted OR = 1.23; 95% CI, 1.05 to 1.44). With morbid obesity, the OR for cardiovascular defects was 1.40 (95% CI, 1.22 to 1.64), and for severe cardiovascular defects, the OR was 1.69 (95% CI, 1.27 to 2.26). There was an increased risk for all specific defects studied among the obese women, but only ventricular septal defects and atrial septal defects reached statistical significance. DISCUSSION: In this sample, a positive association was found between maternal obesity in early pregnancy and congenital heart defects in the offspring. A suggested explanation is undetected type 2 diabetes in early pregnancy, but other explanations may exist.     

Association of parental characteristics with adverse outcomes of adolescent pregnancy

BACKGROUND: It is well-known that pregnancy in adolescence has an increased risk of adverse reproductive outcomes. It remains unclear whether this association is due mainly to the unfavourable sociodemographic status or due solely to biological immaturity of pregnant adolescents. OBJECTIVE: The purpose of this study was to determine the association of parental sociodemographic characteristics with the adverse outcomes of adolescent pregnancy. METHOD: Data from certificates of live births in Taichung County, Taiwan in 1994 of 7994 singleton, first-born babies whose mothers were 15-34 years of age were analysed. The relative risk of having adverse pregnancy outcomes for adolescent subgroups was obtained as compared with that among mothers 20-34 years of age with the same characteristics. The adjusted relative risk of having adverse pregnancy outcomes for each covariate was calculated by a multiple logistic regression analysis. RESULTS: Of 7994 babies born to mothers of 15-34 years of age, 8.3% were born to adolescent mothers. In all age groups, the younger adolescent mothers (15-17 years of age) had the highest percentage of both infants with low birth weight (10.6%) and preterm births (7.1 %). Younger adolescent mothers in almost all sociodemographic categories had higher risks of having both low-birth-weight and preterm births than those of older adolescent mothers. Multiple logistic regression analysis showed that a younger maternal age is the only significant risk factor for having infants with low birth weight (adjusted RR = 2.5, 95% Cl 1.8-4.5 and adjusted RR = 1.7, 95% Cl 1.2-2.6 for younger and older adolescent mothers, respectively) or preterm birth (adjusted RR = 1.9, 95% Cl 1.1- 3.4 and adjusted RR = 1.5, 95% Cl 1.0-2.3 for younger and older adolescent mothers, respectively). CONCLUSIONS: Adolescent pregnancy carries an increased risk of having low-birth-weight and preterm births, and a younger maternal age is causally implicated.      

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.     

Offspring birth weight and parental mortality: prospective observational study and meta-analysis

The authors have investigated associations between offspring size at birth and parental cardiovascular disease mortality among 12,086 mothers and 6,936 fathers of participants in the British 1958 birth cohort. Birth weight was inversely associated with all-cause mortality and cardiovascular mortality in both mothers and fathers. The adjusted hazard ratio of cardiovascular disease mortality for a 1-standard deviation increase in offspring birth weight in mothers was 0.87 (95% confidence interval (CI): 0.82, 0.93) and in fathers was 0.94 (95% CI: 0.89, 0.99). The association was not specific for cardiovascular disease. In fathers, similar weak associations with violent and accidental deaths, stomach cancer, and alcohol- and smoking-related outcomes were found. Weak associations for these outcomes were also found for mothers, but the magnitude of the association with cardiovascular disease was greater than with any other outcomes. In a meta-analysis pooling results from this study with six others, the adjusted hazard ratio of cardiovascular disease mortality among mothers was 0.75 (95% CI: 0.67, 0.84) and that among fathers was 0.93 (95% CI: 0.91, 0.95), with evidence that the difference in effect between mothers and fathers was not due to chance (p < 0.001). The weak association of offspring birth weight with cardiovascular disease in fathers may be due to residual confounding by factors such as socioeconomic position and smoking that they share with the offspring's mother and that would therefore be associated with low offspring birth weight as well as adverse outcomes in the father. The stronger association in mothers is consistent with intergenerational effects on intrauterine growth and with the fetal origins hypothesis.     

Birth weight trends among interracial black and white infants

I examined time trends in low birth weight (LBW) and very low birth weight (VLBW) among interracial compared with single-race infants. Using natality data from 1978 through 1997 for singleton births to black and white parents, I calculated relative risks (RRs) of LBW and VLBW for interracial compared with single-race births, stratified by maternal race and adjusted for maternal characteristics. Among black mothers, interracial births had lower risks of LBW and VLBW than single-race births, and RRs were similar throughout the time period [for example, adjusted RR = 0.76 and 95% confidence interval (CI) = 0.73-0.80 for LBW in 1994-1997]. Among white mothers, interracial infants had higher risks of LBW than single-race infants; however, the adjusted RRs declined over the time period, from 1.22 (95% CI = 1.19-1.27) in 1978-1981 to 1.05 (95% CI = 1.03-1.08) in 1994-1997. Since 1978, there has been some relative improvement in birth outcomes for infants of white mothers and black fathers compared with single-race white births. There was, however, no relative improvement for black mother/black father infants relative to black mother/white father births.     

Using Linked Data to Assess Patterns of Early Intervention (EI) Referral among Very Low Birth Weight Infants

Objectives Access to Early Intervention (EI) services may improve cognitive and behavioral outcomes in very low birth weight infants, but few states have population-based data to evaluate EI outreach efforts. We analyzed Massachusetts (MA) infants born weighing <1,200 g to identify maternal and birth characteristics that predicted EI referral and timing of referral. Methods MA birth and hospital discharge records (Jan. 1998–Sept. 2000) were linked to EI referral records (Jan. 1998–Sept. 2003) via probabilistic and deterministic methods (88% linkage). Timing of EI referral among infants weighing <1,200 g was examined by infant and maternal characteristics using categorical (0–12 months, 12–36 months, or no referral) time comparisons in the crude analysis. Survival functions calculating median time to referral, and adjusted hazard ratios (HR) with 95% confidence intervals (CI) were calculated for continuous time comparisons of EI referral from birth to 36 months. Results Of 1,233 infants weighing <1,200 g, 93.2% were referred to EI. After risk adjustment, referral was more likely among multiple-birth infants (HR = 1.17, 95%CI 1.06–1.30) and less likely among infants <28 weeks (HR = 0.70; 95%CI 0.64–0.77) or with low Apgar scores (<5 at 5 min; HR = 0.75; 95%CI 0.62–0.92). EI referrals were lower for infants of black non-Hispanic mothers, and mothers without private insurance (HR = 0.85; 95%CI 0.74–0.98 and HR = 0.77; 95%CI 0.68–0.86, respectively). Conclusions In MA, most infants born <1,200 g are referred to EI, but disparities exist. Analysis of linked population-based health and developmental services can inform programs in order to reduce disparities and improve access for all high-risk infants.     

Ethnic differences in the incidence of the sudden infant death syndrome (SIDS) in Victoria, Australia 1985–1989

Summary. In order to describe ethnic differences in the incidence of the sudden infant death syndrome (SIDS) records of all livebirths in the State of Victoria, Australia, 1985–1989, excluding those who died in the first month of life, were linked to death certificates. Cases were defined as infants dying with a diagnosis of SIDS between 1 month and 1 year of age ( n = 601) from the cohort of 308052 neonatal survivors. Ethnicity was defined by the mother's country of birth. The SIDS incidence was 2.04/1000 in infants of Australian-born mothers. The relative risk of SIDS was 0.28 (95% confidence interval (CI) 0.15,0.55) in infants whose mothers had been born in Southern Europe and 0.48 (95% CI 0.29, 0.78) in infants whose mothers had been born in Asia. SIDS in infants of Australian-born mothers was associated with low maternal age, high parity, marital status other than married, male sex, multiple birth, low birthweight and preterm birth. After adjustment for those factors in a case-control analysis using a logistic regression model the adjusted odds ratio for SIDS was 0.34 (95% CI 0.17, 0.69) comparing infants whose mothers were born in Southern Europe with infants of Australian-born mothers, and 0.60 (95% CI 0.35, 1.04) for infants whose mothers were born in Asia, compared with infants of the Australian-born. Thus there are substantial ethnic differences in SIDS which are not explained by the classic social and perinatal risk factors.     

Breastfeeding Practices among Adolescent Mothers and Associated Factors in Bangladesh (2004–2014)

Optimal breastfeeding practices among mothers have been proven to have health and economic benefits, but evidence on breastfeeding practices among adolescent mothers in Bangladesh is limited. Hence, this study aims to estimate breastfeeding indicators and factors associated with selected feeding practices. The sample included 2554 children aged 0–23 months of adolescent mothers aged 12–19 years from four Bangladesh Demographic and Health Surveys collected between 2004 and 2014. Breastfeeding indicators were estimated using World Health Organization (WHO) indicators. Selected feeding indicators were examined against potential confounding factors using univariate and multivariate analyses. Only 42.2% of adolescent mothers initiated breastfeeding within the first hour of birth, 53% exclusively breastfed their infants, predominant breastfeeding was 17.3%, and 15.7% bottle-fed their children. Parity (2–3 children), older infants, and adolescent mothers who made postnatal check-up after two days were associated with increased exclusive breastfeeding (EBF) rates. Adolescent mothers aged 12–18 years and who watched television were less likely to delay breastfeeding initiation within the first hour of birth. Adolescent mothers who delivered at home (adjusted OR = 2.63, 95% CI:1.86, 3.74) and made postnatal check-up after two days (adjusted OR = 1.67, 95% CI: 1.21, 2.30) were significantly more likely to delay initiation breastfeeding within the first hour of birth. Adolescent mothers living in the Barisal region and who listened to the radio reported increased odds of predominant breastfeeding, and increased odds for bottle-feeding included male infants, infants aged 0–5 months, adolescent mothers who had eight or more antenatal clinic visits, and the highest wealth quintiles. In order for Bangladesh to meet the Sustainable Development Goals (SDGs) 2 and 3 by 2030, breastfeeding promotion programmes should discourage bottle-feeding among adolescent mothers from the richest households and promote early initiation of breastfeeding especially among adolescent mothers who delivered at home and had a late postnatal check-up after delivery.     

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.     

The exposure of nonsmoking and smoking mothers to environmental tobacco smoke during different gestational phases and fetal growth

We studied the impact of maternal exposure to environmental tobacco smoke (ETS) on birth weight (BW), low birth weight (LBW), and intrauterine growth retardation (IUGR) according to self-reported maternal smoking habits in a sample of 6,866 singleton births. We obtained data about parental characteristics and maternal active smoking (AS) and passive smoking at delivery via maternal questionnaires and medical records. We used three categories of smoking habits (nonsmokers and those who smoked 1-10 or >10 cigarettes per day) and defined ETS exposure as greater than or equal to 5 cigarettes per day smoked by others in the mother's presence. We used multiple regression and logistic regression procedures with adjustment for many associated covariates. We observed a significant reduction of the mean BW in infants of AS mothers. This reduction was only marginal for mothers who stopped smoking after recognizing their pregnancy. ETS exposure in 1,797 of 5,507 nonsmoking mothers reduced the mean BW of their infants by 53 g [95% confidence interval (CI), 24-82 g]. ETS exposure also significantly reduced BW in babies of AS mothers by 92 g (CI, 21-113 g) compared with BW of ETS-nonexposed AS mothers. The adjusted odds ratio (AOR) of LBW for ETS-exposed AS mothers was two times the LBW risk of ETS-nonexposed AS mothers(2.02; CI, 1.11-3.67); the AOR of ETS-exposed nonsmoking mothers was 1.51 (CI, 1.02-2.26). The AOR of IUGR for this group did not differ from unity (1.08; CI, 0.82-1.43). However, ETS exposure increased the AOR of IUGR for AS mothers from 1.64 (CI, 1.06-2.53) to 2.13 (CI, 1.70-2.67). ETS exposure reduced the BW of infants of nonsmoking mothers and contributed to additional BW reduction in infants of AS mothers. ETS exposure increased the risk of LBW but not that of IUGR in babies of nonsmoking mothers.     

Relation of Maternal Low Birth Weight to Infant Growth Retardation and Prematurity

Objectives: This study sought to determine the relationship between maternal birth weight, infant intrauterine growth retardation, and prematurity. Methods: Stratified and logistic regression analyses were performed on a dataset of computerized Illinois vital records of African American (N = 61,849) and White (N = 203,698) infants born between 1989 and 1991 and their mothers born between 1956 and 1975. Results: Race-specific rates of small-for-gestational age (weight-for-gestational age <10th percentile) and preterm (<37 weeks) infants rose as maternal birth weight declined. The adjusted (controlling for maternal age, education, marital status, parity, prenatal care utilization, and cigarette smoking) odds ratio (95% confidence interval) of small-for-gestational age for maternal low birth weight (<2500 g) among African Americans and Whites were 1.7 (1.1.4–1.9) and 1.8 (1.7–2.0), respectively. The adjusted odds ratio (95% confidence interval) of prematurity for maternal low birth weight (<2500 g) among African Americans and Whites were 1.6 (1.3–1.9) and 1.3 (1.0–1.6), respectively. The racial disparity in the rates of small-for-gestational age and prematurity persisted independent of maternal birth weight: adjusted odds ratio equaled 2.2 (2.1–2.4) and 1.5 (1.4–1.7), respectively. Conclusions: Maternal low birth weight is a risk factor for infant intrauterine growth retardation and prematurity among African Americans independent of maternal risk status during pregnancy; it is a risk factor for infant intrauterine growth retardation among Whites. Maternal low birth weight fails to explain the racial disparity in the rates of small-for-gestational age and premature infants.     

Impact of reduced maternal exposures to wood smoke from an introduced chimney stove on newborn birth weight in rural Guatemala

Background: A growing body of evidence indicates a relationship between household indoor air pollution from cooking fires and adverse neonatal outcomes, such as low birth weight (LBW), in resource-poor countries.Objective: We examined the effect of reduced wood smoke exposure in pregnancy on LBW of Guatemalan infants in RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects).Methods: Pregnant women (n = 266) either received a chimney stove (intervention) or continued to cook over an open fire (control). Between October 2002 and December 2004 we weighed 174 eligible infants (69 to mothers who used a chimney stove and 105 to mothers who used an open fire during pregnancy) within 48 hr of birth. Multivariate linear regression and adjusted odds ratios (ORs) were used to estimate differences in birth weight and LBW (< 2,500 g) associated with chimney-stove versus open-fire use during pregnancy.Results: Pregnant women using chimney stoves had a 39% reduction in mean exposure to carbon monoxide compared with those using open fires. LBW prevalence was high at 22.4%. On average, infants born to mothers who used a stove weighed 89 g more [95% confidence interval (CI), –27 to 204 g] than infants whose mothers used open fires after adjusting for maternal height, diastolic blood pressure, gravidity, and season of birth. The adjusted OR for LBW was 0.74 (95% CI, 0.33–1.66) among infants of stove users compared with open-fire users. Average birth weight was 296 g higher (95% CI, 109–482 g) in infants born during the cold season (after harvest) than in other infants; this unanticipated finding may reflect the role of maternal nutrition on birth weight in an impoverished region.Conclusions: A chimney stove reduced wood smoke exposures and was associated with reduced LBW occurrence. Although not statistically significant, the estimated effect was consistent with previous studies.     

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 factors for cryptorchidism: a nested case-control study

Summary. .A nested case-control study of cryptorchidism (i.e. undescended testicles) was undertaken as part of a hospital-based cohort study of 6699 singleton male neonates in New York City. Since some of the cryptorchid infants experienced spontaneous descent of their testes, separate analysis was performed for this third group of late descenders' ( n = 140). Cases ( n = 63) represented infants whose testes remained undescended at the one year assessment. Controls ( n =219) represented the next male infant who was delivered immediately after an infant who was cryptorchid at birth. The only independent risk factors for cryptorchidism were Asian ethnic group (adjusted odds ratio (OR) = 3.90,95% confidence interval (CI) = 1.22-12.41), swollen legs or feet during pregnancy (adjusted OR=2.16, 95% CI = 1.15-4.04), a family history of cryptorchidism (adjusted OR=4.32, 95% CI = 1.91-9.80), low birthweight (adjusted OR = 4.10, 95% CI = 1.39-12.08), and use of analgesics during pregnancy (adjusted OR = 1.93/95% CI = 1.03-3.62). Multiple logistic regression analysis was also performed to identify those factors that were associated with late testicular descent. In this analysis the independent risk factors were black or Hispanic ethnicity (adjusted OR = 2.05, 95% CI = 1.09-3.83), a family history of cryptorchidism (adjusted OR = 4.25,95% CI = 1.84-9.78), consumption of cola-containing drinks during the pregnancy (adjusted OR = 2.09, 95% CI = 1.10-3.99), a low birthweight delivery (adjusted OR = 9.78, 95% CI = 3.39-28.20), and preterm birth (adjusted OR = 4.01, 95% CI = 1.66-9.70).     

Low Birth Weight Across Generations

Objectives: This study sought to determine the relationship between maternal birth weight, prenatal care usage, and infant birth weight. Methods: Stratified and logistic regression analyses were performed on a dataset of computerized Illinois vital records of White (N = 187,074) and African-American (N = 58,856) infants born between 1989 and 1991 and their mothers born between 1956 and 1975. Results: Among White mothers who received adequate prenatal care, the low birth weight (<2500 g) rate was 4% for infants of former low birth weight mothers (N = 5230) compared to 2.1% for infants of former nonlow birth weight mothers (N = 93,011), relative risk equaled 1.9(1.7–2.2); the population attributable risk of maternal low birth weight was 4.1%. Among African American mothers who received adequate prenatal care, the low birth weight rate was 15% for infants of former low birth weight mothers (N = 2196) compared to 7.2% for infants of former nonlow birth weight mothers (N = 14,607), relative risk equaled 2.1(1.9–2.4); the population attributable risk of maternal low birth weight was 10.9%. The maternal–infant birth weight associations were consistent across all maternal age, education, marital status, and prenatal care categories. Conclusions: Maternal low birth weight is a risk factor for infant low birth weight independent of risk status during the current pregnancy. A greater percentage of low birth weight African American (compared to White) infants are attributable to maternal low birth weight.