A review of low birth weight: predictors, precursors and morbidity outcomes

Low and High Birth Weight in a Hospital Population in Qassim, Saudi Arabia: An Analysis of Clinical Cutoff Values

BACKGROUND

Establishing cutoff values for low birth weight (LBW) and high birth weight (HBW) is crucial for clinical practice. This study aimed to determine these values in Saudi Arabia.

METHOD

A retrospective study in 2022 analyzed the birth weights of 1605 neonates. The 10th and 90th percentiles were calculated to define LBW and HBW.

RESULTS

LBW was defined as <2450 g (10th percentile), with an incidence of 10.5%. HBW was >3650 g (90th percentile), with a prevalence of 10.3%. Comparing the WHO's LBW definition (<2500 g) revealed significant differences but high agreement (kappa = 0.962). HBW had a prevalence of 2.4% using a 4000 g cutoff, with low agreement (Kappa = 0.357).

CONCLUSIONS

This study suggests an LBW cutoff at 2450 g and an HBW cutoff at 3650 g in Saudi Arabia. A birth weight range of 2450-3650 g is considered normal, reducing unnecessary healthcare interventions.

Trajectories in county-level Low Birthweight Rates and Associated Contextual Factors in the United States, 2016-2021

Introduction

Infants with low birthweight (less than 2500 grams) have greater risk of mortality, long-term neurologic disability and chronic diseases such as diabetes and cardiovascular disease as compared to infants with normal birthweight. This study examined the trajectories of low birthweight rate in the U.S. across the metropolitan and non-metropolitan counties over the time period of 2016-2021 and the associated contextual factors.

Methods

This longitudinal study utilized data on 21,759,834 singleton births across 3,108 counties. Data on birthweight and maternal sociodemographic and behavioral characteristics was obtained from the National Center for Health Statistics. A generalized estimating equations model was used to examine the association of county-level contextual variables with low birthweight rates.

Results

A significant increase in low birthweight rates was observed across the counties over the duration of the study. Large metro and small metro counties had significantly higher low birthweight rates as compared to non-metro counties. High percentage of Black women, underweight women, age more than 35 years, lack of prenatal care, uninsured population, and high violent crime rate was associated with an increase in low-birth-weight rates. Other contextual characteristics (percentage of married women, American Indian/Alaskan Native women, and unemployed population) differed in their associations with low birthweight rates depending on county metropolitan status.

Conclusions

Our study findings emphasize the importance of developing interventions to address geographical heterogeneity in low birthweight burden, particularly for metropolitan areas and communities with vulnerable racial/ethnic and socioeconomic groups.

Impact of the trait anxiety during pregnancy on birth weight: an observational cohort study

To explore the effects of antenatal anxiety on fetal growth an observational cohort study was performed, including a cohort of 204 women with singleton pregnancies during the strict lockdown of the COVID-19 pandemic in 2020. Psychosocial factors, maternal demographics, obstetric outcomes, social support (Medical Outcomes Study Social Support Survey, MOS-SSS), and symptoms of anxiety (State-Trait Anxiety Inventory, STAIs and STAIt) and depression (Edinburgh Postpartum Depression Scale, EPDS) were studied as potential predictors of low birth weight. Main outcome measures were birth weight, head circumference and length. Results showed a negative correlation between STAIt score (trait anxiety) and birth weight percentile (r = -0.228, p = .047). In the univariate linear regression analysis, a lower maternal weight and BMI before pregnancy, parity, increased STAIt score and preterm birth below 37 weeks of gestation (p = .008, p = .015, p = .028, p = .047 and p = .022, respectively) were identified as predictive risk factors for low birth weight, whereas in the multivariate lineal regression analysis only a lower maternal weight before pregnancy and an increased STAIt score were independent predictors for low birth weight (p = .020, p = .049, respectively). To conclude, anxiety during pregnancy impacts birth weight, and specifically the trait anxiety, is a predictor for low birth weight.

Mother-level random effect in the association between PM2.5 and fetal growth: A population-based pregnancy cohort

BACKGROUND

A growing body of literature reports associations between exposure to particulate matter with diameter ≤2.5 μm (PM_2.5) during pregnancy and birth outcomes. However, findings are inconsistent across studies.

OBJECTIVES

To assess the association between PM_2.5 and birth outcomes of fetal growth in a cohort with high prevalence of siblings by multilevel models accounting for geographical- and mother-level correlations.

METHODS

In Israel, we used Maccabi Healthcare Services data to establish a population-based cohort of 381,265 singleton births reaching 24-42 weeks' gestation and birth weight of 500-5000 g (2004-2015). Daily PM_2.5 predictions from a satellite-based spatiotemporal model were linked to the date of birth and maternal residence. We generated mean PM_2.5 values for the entire pregnancy and for exposure periods during pregnancy. Associations between exposure and birth outcomes were modeled by using multilevel logistic regression with random effects for maternal locality of residence, administrative census area (ACA) and mother.

RESULTS

In fully adjusted models with a mother-level random intercept only, a 10-μg/m³ increase in PM_2.5 over the entire pregnancy was positively associated with term low birth weight (TLBW) (Odds ratio, OR = 1.25, 95% confidence interval, CI: 1.09,1.43) and small for gestational age (SGA) (OR = 1.15, 95% CI: 1.06,1.26). Locality- and ACA-level effects accounted for <0.4% of the variance while mother-level effects explained ∼50% of the variability. Associations varied by exposure period, infants' sex, birth order, and maternal pre-pregnancy BMI.

CONCLUSIONS

Consideration of mother-level variability in a region with high fertility rates provides new insights on the strength of associations between PM_2.5 and birth outcomes.

Surface mining and low birth weight in central appalachia

BACKGROUND

Surface mining has become a significant method of coal mining in the Central Appalachian region of the eastern United States alongside the traditional underground mining. Concerns have been raised about the health effects of this surface mining, particularly mountaintop removal mining where coal is mined upon steep mountaintops by removing the mountaintop through clearcutting forests and explosives.

METHODS

We used a control group design with a pretest and a posttest to assess the associations of surface mining in Central Appalachia with low birth weight and other adverse birth outcomes. The pretest period is 1977-1989, a period of low surface mining activity. We consider three posttest periods: 1990-1998, 1999-2011 and 2012-2017, with 1999-2011 as the primary analysis and the other periods as secondary analyses. Surface mining in Central Appalachia increased after 1989, partly resulting from the Clean Air Act Amendments of 1990 which made surface mining in Appalachia more financially attractive. For the primary analysis, we fit a logistic regression model of the primary outcome (low birth weight, <2500 g) on dummy variables for county and year; individual level maternal/infant covariates (maternal race, maternal age, infant sex and whether birth was a multiple birth); and the amount of surface mining during the year of the birth in the maternal county of residence.

RESULTS

Our analysis sample consisted of 783,328 infants -- 482,284 infants born from 1977 to 2017 to women residing in substantial surface mining activity counties and 301,044 infants born from 1977 to 2017 to women residing in matched control counties. Compared to the pre-period of low surface mining from 1977 to 1989, for the primary analysis posttest period of 1999-2011, there was an estimated relative increase in low birth weight in surface mining counties compared to matched control counties that was not statistically significant (odds ratio for a 5 percentage point increase in area disturbed by surface mining: 1.07, 95% confidence interval (0.96, 1.20), p-value: .22). For the secondary analysis posttest period of 1990-1998, there was no increase (odds ratio: 0.91, 95% confidence interval: (0.74, 1.13), p-value: .41). For the secondary analysis posttest period of 2012-2017, there was a statistically significant relative increase (odds ratio: 1.28, 95% confidence interval: (1.08, 1.50), p-value: .004). Qualitatively similar results were found for the outcomes of very low birth weight, preterm birth and small-for-gestational age.

CONCLUSIONS

We examined the hypothesis that surface mining activity in Central Appalachia contributes to low birth weight using an observational study. We found evidence in secondary analyses that surface mining was associated with low birth weight in the 2012-2017 time period and potentially beginning in the early to mid 2000's. Evidence for an association was not found prior to 2000. A potential explanation for this pattern of association is that surface mining caused an increase in low birth weight but its onset was delayed. Future research is needed to clarify the findings and if replicated, identify the mechanism necessary to mitigate the impacts of mining on adverse birth outcomes.

Investigating the impact of Hurricane Maria on an ongoing birth cohort in Puerto Rico

Prior to Hurricane Maria, Puerto Rico already had 200+ hazardous waste sites, significant contamination of water resources, and among the highest rates of preterm birth in the US. To address these issues, the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) Center was formed in 2010 to investigate prenatal environmental exposures, particularly phthalates, and adverse birth outcomes. Recent work from the PROTECT study confirms that in utero exposure to certain phthalates is associated with shorter gestation and increased risk of preterm birth. However, previous research also suggests that pregnant women who experience a natural disaster such as Hurricane Maria are at higher risk of adverse birth outcomes, but it is unknown whether this is due to stress, hazardous exposures, or a combination of factors. Thus, the aim of this analysis was to characterize hurricane-related changes in phthalate exposures and experiences within the PROTECT cohort. Among 176 participants who were pregnant during or within 5 months after Maria, 122 completed a questionnaire on hurricane-related experiences. Questionnaire results and biomarkers of exposure suggest that participants did not have regular access to fresh foods and water during hurricane recovery, and almost half reported structural damage to their home. In addition, biomarker concentrations of phthalates commonly used in food packaging were higher among participants post-hurricane, while phthalates commonly used in personal care products were lower compared to pre-hurricane levels. Hurricane-related increases in phthalate exposure, as well as widespread structural damage, food and water shortages, and long-term absence of electricity and cell phone service, likely increased the risk of adverse birth outcomes among this already vulnerable population.

Timing and Duration of Pre- and Postnatal Homelessness and the Health of Young Children

: media-1vid110.1542/5804912861001PEDS-VA_2017-4254Video Abstract OBJECTIVES: Prenatal homelessness is associated with elevated risks of adverse neonatal outcomes. How the timing and duration of homelessness during pregnancy and/or a child's early life relate to postnatal child health is unclear.

METHODS

We interviewed 20 571 low-income caregivers of children <4 years old in urban pediatric clinics and/or emergency departments in 5 US cities. Categories of homelessness timing were prenatal, postnatal, both, or never; postnatal duration was >6 months or <6 months.

RESULTS

After controlling for birth outcomes and other potential confounders, compared with never-homeless children, children who were homeless both pre- and postnatally were at the highest risk of the following: postneonatal hospitalizations (adjusted odds ratio [aOR] 1.41; confidence interval [CI] 1.18-1.69), fair or poor child health (aOR 1.97; CI 1.58-2.47), and developmental delays (aOR 1.48; CI 1.16-1.89). There was no significant association with risk of underweight (aOR 0.95; CI 0.76-1.18) or overweight status (aOR 1.07; CI 0.84-1.37). Children <1 year old with >6 months of homelessness versus those who were never homeless had high risks of fair or poor health (aOR 3.13; CI 2.05-4.79); children 1 to 4 years old who were homeless for >6 months were at risk for fair or poor health (aOR 1.89; CI 1.38-2.58).

CONCLUSIONS

After controlling for birth outcomes, the stress of prenatal and postnatal homelessness was found to be associated with an increased risk of adverse pediatric health outcomes relative to those who were never homeless. Interventions to stabilize young families as quickly as possible in adequate and affordable housing may result in improved pediatric health outcomes.

Women's mental health during pregnancy: A participatory qualitative study

BACKGROUND/OBJECTIVES

British public health and academic policy and guidance promotes service user involvement in health care and research, however collaborative research remains underrepresented in literature relating to pregnant women's mental health. The aim of this participatory research was to explore mothers' and professionals' perspectives on the factors that influence pregnant women's mental health.

METHOD

This qualitative research was undertaken in England with the involvement of three community members who had firsthand experience of mental health problems during pregnancy. All members of the team were involved in study design, recruitment, data generation and different stages of thematic analysis. Data were transcribed for individual and group discussions with 17 women who self-identified as experiencing mental health problems during pregnancy and 15 professionals who work with this group. Means of establishing trustworthiness included triangulation, researcher reflexivity, peer debriefing and comprehensive data analysis.

FINDINGS

Significant areas of commonality were identified between mothers' and professionals' perspectives on factors that undermine women's mental health during pregnancy and what is needed to support women's mental health. Analysis of data is provided with particular reference to contexts of relational, systemic and ecological conditions in women's lives.

CONCLUSIONS

Women's mental health is predominantly undermined or supported by relational, experiential and material factors. The local context of socio-economic deprivation is a significant influence on women's mental health and service requirements.

First Trimester Phthalate Exposure and Infant Birth Weight in the Infant Development and Environment Study

Phthalate exposure is widespread among pregnant women but whether it is related to fetal growth and birth weight remains to be determined. We examined whether first trimester prenatal phthalate exposure was associated with birth weight in a pregnancy cohort study. We recruited first trimester pregnant women from 2010-2012 from four centers and analyzed mother/infant dyads who had complete urinary phthalate and birth record data (N = 753). We conducted multiple linear regression to examine if prenatal log specific gravity adjusted urinary phthalate exposure was related to birthweight in term and preterm (≤37 weeks) infants, stratified by sex. We observed a significant association between mono carboxy-isononyl phthalate (MCOP) exposure and increased birthweight in term males, 0.13 kg (95% CI 0.03, 0.23). In preterm infants, we observed a 0.49 kg (95% CI 0.09, 0.89) increase in birthweight in relation to a one log unit change in the sum of di-ethylhexyl phthalate (DEHP) metabolite concentrations in females (N = 33). In summary, we observed few associations between prenatal phthalate exposure and birthweight. Positive associations may be attributable to unresolved confounding in term infants and limited sample size in preterm infants.

Prevalence of very low birthweight, malformation, and low Apgar score among newborns in Brazil according to maternal urban or rural residence at birth

AIM

Adverse birth outcomes are a major public health issue in rural areas, where several environmental risk factors, including pesticides, may endanger the health of women of reproductive age. We investigated the prevalence of selected birth outcomes among newborns from mothers living in urban and rural areas of a Brazilian municipality.

METHODS

Information about all live births that occurred between 2004 and 2006 in the Municipality of Nova Friburgo, Brazil, was retrieved from the Live Birth Information System. Newborns were classified as rural or urban, according to the mother's residence address.

RESULTS

Newborns from rural areas had a higher prevalence of very low-birthweight, low Apgar score, and malformation. On Poisson regression with adjustment for several confounders, rural offspring were more likely to have the aforementioned outcomes.

CONCLUSIONS

Women in rural areas are at higher risk of giving birth to an infant with very low-birthweight, low 5-min Apgar score and malformations detectable at birth, regardless of socioeconomic and gestational conditions.

Pregnancy intentions, maternal behaviors, and infant health: investigating relationships with new measures and propensity score analysis

The premise that unintended childbearing has significant negative effects on the behavior of mothers and on the health of infants strongly influences public health policy and much of current research on reproductive behaviors. Yet, the evidence base presents mixed findings. Using data from the U.S. National Survey of Family Growth, we employ a measure of pregnancy intentions that incorporates the extent of mistiming, as well as the desire scale developed by Santelli et al. (Studies in Family Planning, 40, 87-100, 2009). Second, we examine variation in the characteristics of mothers within intention status groups. Third, we account for the association of mothers' background characteristics with their pregnancy intentions and with the outcomes by employing propensity score weighting. We find that weighting eliminated statistical significance of many observed associations of intention status with maternal behaviors and birth outcomes, but not all. Mistimed and unwanted births were still less likely to be recognized early in pregnancy than intended ones. Fewer unwanted births received early prenatal care or were breast-fed, and unwanted births were also more likely than intended births to be of low birth weight. Relative to births at the highest level of the desire scale, all other births were significantly less likely to be recognized early in pregnancy and to receive early prenatal care.

The association of PM(2.5) with full term low birth weight at different spatial scales

There is interest in determining the relationship between fine particulate matter air pollution and various health outcomes, including birth outcomes such as term low birth weight. Previous studies have come to different conclusions. In this study we consider whether the effect may vary by location and gestational period. We also compare results when using different spatial resolutions for the air concentration estimates. Among the seven states considered, New Jersey and New York had the highest PM2.5 levels (average full gestation period exposures of 13 µg/m(3)) and the largest rate of low birth weight births (2.6 and 2.8%, respectively); conversely Utah and Minnesota had the lowest PM2.5 levels (9 µg/m(3)) and the lowest rates of low birth weight births (2.1 and1.9%, respectively). There is an association between PM2.5 exposure and low birth weight in New York for the full gestation period and all three trimesters, in Minnesota for the full gestation period and the first and third trimesters, and in New Jersey for the full gestation period and the first trimester. When we pooled the data across states, the OR for the full gestation period was 1.030 (95% CI: 1.022-1.037) and it was highest for the first trimester (OR 1.018; CI: 1.013-1.022) and decreasing during the later trimesters. When we used a finer spatial resolution, the strengths of the associations tended to diminish and were no longer statistically significant. We consider reasons why these differences may occur and their implications for evaluating the effects of PM2.5 on birth outcomes.

Contribution of psychopathology, psychosocial problems and substance use to urban and rural differences in birth outcomes

BACKGROUND

Urban residence contributes to disparities in preterm birth (PTB) and birth weight. As urban and rural pregnant populations differ in individual psychopathological, psychosocial and substance use (PPS) risks, we examined the extent to which PTB and birth weight depend on the (accumulative) effect of PPS risk factors and on demographic variation.

METHODS

Follow-up study from 2010 to 2012 among 689 urban and 348 rural pregnant women. Urbanity was based on the population density per ZIP code. Women completed the validated Mind2Care instrument questionnaire, which includes the Edinburgh Depression Scale, and demographic, obstetric and PPS questions. Pregnancy outcomes were extracted from medical records. With regression analyses we assessed crude and adjusted associations between residence and birth outcomes, adjusted for available confounding or mediating factors.

RESULTS

PTB was significantly associated with segregation, maternal age (<25 and ≥ 35 years old), primiparity, smoking during pregnancy and the accumulation of risks, but not with residence (urban, 4%; rural, 7%; P = 0.16). Mean birth weight was significantly lower for urban babies (crude β: -174; P < 0.001). Adjusting for potential confounders and mediators, non-Western ethnicity, parity and smoking during pregnancy significantly decreased birth weight besides residence. The accumulative effect of PPS risk factors significantly decreased birth weight (β: -58 g per risk factor; P < 0.001).

CONCLUSION

PTB was not associated with residence. The lower birth weight of urban babies remains significant after adjusting for urban risks, such as non-Western ethnicity and the PPS risk factor smoking. The accumulation of multiple (moderate) PPS risks accounts partly for the urban effect.

Low birth weight and health expenditures from birth to late adolescence

OBJECTIVES

The aim of this paper is to analyze the impact of low birth weight (LBW) and very low birth weight (VLBW) on health care utilization in childhood and early adolescence.

DATA/METHODS

Using Austrian health insurance administrative panel data linked to the Austrian birth register, we estimate the effects of LBW and VLBW in comparison to normal birth weight (NBW) on the number of days spent in the hospital and on expenditures for medical assistance and medical drugs among children and young adults between birth and 21 years of age. To account for the time-invariant heterogeneity of mothers, we control for sibling fixed effects.

RESULTS

We find that, in comparison to their NBW counterparts, LBW infants spend more days hospitalized and more is spent on medical drugs (particularly on anti-infectives) for them in their first year of life. Although the absolute differences in health service utilization between NBW and LBW groups diminish over time, LBW newborns still spend more days hospitalized, and their medical drug and medical assistance expenses are significantly higher in early childhood. During compulsory schooling, we observe a shift toward diseases of the nervous system and mental and behavioral disorders among children born with LBW. Some of these effects persist until early adulthood.

CONCLUSIONS

We argue for further counseling efforts for expectant mothers on the determinants and risk factors of LBW. Moreover, pre-school screenings especially tailored to LBW infants with a particular focus on mental health and behavioral disorders can be easily integrated in the existing postnatal mother-child care program in Austria to mitigate the consequences of negative conditions during pregnancy.

Improved birth weight for Black infants: outcomes of a Healthy Start program

OBJECTIVES

We determined whether participation in Healthy Babies Healthy Start (HBHS), a maternal health program emphasizing racial equity and delivering services through case management home visitation, was associated with improved birth outcomes for Black women relative to White women.

METHODS

We used a matched-comparison posttest-only design in which we selected the comparison group using propensity score matching. Study data were generated through secondary analysis of Michigan state- and Kalamazoo County-level birth certificate records for 2008 to 2010. We completed statistical analyses, stratified by race, using a repeated-measures generalized linear model.

RESULTS

Despite their smoking rate being double that of their matched counterparts, Black HBHS participants delivered higher birth-weight infants than did Black nonparticipants (P = .05). White HBHS participants had significantly more prenatal care than did White nonparticipants, but they had similar birth outcomes (P = .7 for birth weight; P = .55 for gestation).

CONCLUSIONS

HBHS participation is associated with increased birth weights among Black women but not among White women, suggesting differential program gains for Black women.

Exposure of lead to mothers and their new born infants, residents of industrial and domestic areas of Pakistan

Prenatal and early-life exposure to lead (Pb) is hypothesized to have adverse effects on childhood health. The aim of this study was to evaluate the prenatal exposure to Pb and its adverse effects on mothers and their infants who are residents of industrial (exposed) and domestic areas (referents) in Karachi, Pakistan. The biological samples (scalp hair and blood) of mother-infants pairs were analyzed for Pb levels by atomic absorption spectrometry after microwave-assisted acid digestion method. The Pb levels in scalp hair and blood samples of exposed mothers were found in the range of 7.52-8.70 μg/g and 115-270 μg/L, respectively, which were significantly higher than those values obtained for referent mothers (p < 0.001). The Pb levels in the blood (umbilical cord) and hair of neonates of exposed mother that were found in the range of 83-178 μg/L and 4.95-7.23 μg/g, respectively, were significantly higher than the obtained values of referent neonates (p > 0.001). The correlation between maternal and cord blood of both groups was found in the range of 0.708-0.724 (p < 0.01). It was observed that there were higher Pb burdens in exposed mothers and their infants as compared to referent mothers-neonates.

No association between antenatal common mental disorders in low-obstetric risk women and adverse birth outcomes in their offspring: results from the CDS study in Ghana and Côte D'Ivoire

Background

Evidence linking common mental disorders (CMD) in pregnant women to adverse birth outcomes is inconsistent, and studies often failed to control for pregnancy complications. This study aimed to explore the association between antenatal depression and anxiety symptoms and birth outcomes in a low-obstetric risk sample of mother/child dyads in Ghana and Côte d’Ivoire.

Methods

In 2010-2011, a prospective cohort of 1030 women in their third trimester in Ghana and Côte d’Ivoire was enrolled. Depression and anxiety were assessed in the third trimester using the Patient Health Questionnaire depression module and the 7-item Generalized Anxiety Disorder scale. 719 mother/child dyads were included in the analysis. We constructed multivariate regression models to estimate the association between CMD and low birth weight (LBW), and preterm birth (PTB) to control for potential confounders.

Results

The prevalence of depression and anxiety symptoms were 28.9% and 14.2% respectively. The mean birth weight was 3172.1g (SD 440.6) and the prevalence of LBW was 1.7%. The mean gestational age was 39.6 weeks and the proportion of PTB was 4%. Multivariate linear regression revealed no significant association between maternal depression (B=52.2, 95% CI -18.2 122.6, p=0.15) or anxiety (B=17.1, 95% CI -74.6 108.7, p=0.72) and birth weight. Yet, low socio-economic status, female sex of the child, and younger maternal age were associated with lower birth weight. Multivariate logistic regression suggested no significant association between maternal depression (OR: 2.1, 95% CI 0.8 5.6, p=0.15) or anxiety (OR: 1.8, 95% CI 0.6 5.5, p=0.29) with PTB.

Conclusions

Our data suggests that depression and/or anxiety in the 3^rd trimester of pregnancy are not independent predictors of adverse birth outcomes in low obstetric risk women. The role of pregnancy complications as confounders or effect modifiers in studies of maternal CMD and their impact on birth outcomes should be investigated.

Smaller pelvic size in pregnant adolescents contributes to lower birth weight

Adolescent pregnancy is associated with low birth weight. This has been explained by socioeconomic or emotional factors. However, an adolescent's pelvis may not be completely developed and this can contribute to impairing fetal growth. Our aim was to compare the relationship between pelvic size and birth weight among adolescents and adult mothers. A cross-sectional study was carried out at Instituto de Medicina Infantil Professor Fernando Figueira (IMIP), Brazil. We studied 125 healthy adolescents and 207 healthy adult women, all of whom were primiparous with a singleton term and low-risk pregnancy. The conjugate, intercristal and interspinous diameters were assessed by the Collins pelvimeter. The effect of pelvic size on the birth weight was evaluated using principal component analysis and multiple linear regression model. The mean pelvic size was smaller in adolescent mothers compared to adult ones (35.1 cm vs. 37.5 cm; p<0.001; t-test). After adjusting for other confounding variables, the predicted birth weights corresponding to these mean values of pelvic size were: 3020±27 g for adolescent mothers and 3145±26 g for adult mothers and showed a significant difference (p<0.001). We concluded that a pelvis that is less than fully developed in adolescents, as assessed by pelvic size, may contribute to lower birth weight in adolescent mothers.

Nutritional management of the low birth weight/preterm infant in community settings: a perspective from the developing world

Globally, about 20 million infants are born with low birth weight (LBW; <2500 g). Of all LBW infants, approximately 95% are born in developing countries. The greatest incidence of LBW occurs in South-Central Asia; the second greatest is in Africa. The two main reasons for LBW are preterm birth (<37 weeks) and intrauterine growth restriction (IUGR), which are risk factors for increased morbidity and mortality in newborn infants. Maternal nutrition status is one of the most important risk factors for LBW/IUGR. Providing balanced protein energy and multiple micronutrient supplements to pregnant women will reduce incidence of IUGR. Calcium supplementation during pregnancy will reduce the incidence of pre-eclampsia and preterm birth in developing countries. Exclusive breastfeeding is protective for a mother and her infant and has been shown to reduce morbidity and mortality in infancy. Kangaroo mother care for preterm infants will reduce severe morbidity and mortality as well. Community-based intervention packages are among the most effective methods of reducing morbidity and mortality in mothers and children. Future research should focus on improving triage of preterm and IUGR infants. Exclusive breastfeeding should be promoted, and appropriate alternative food supplements should be provided when breastfeeding is not possible.

Ambient air pollution and term birth weight in Texas from 1998 to 2004

Previous studies have explored the association between air pollution levels and adverse birth outcomes such as lower birth weight. Existing literature suggests an association, although results across studies are not consistent. Additional research is needed to confirm the effect, investigate the exposure window of importance, and distinguish which pollutants cause harm. We assessed the association between ambient pollutant concentrations and term birth weight for 1,548,904 births in TX from 1998 to 2004. Assignment of prenatal exposure to air pollutants was based on maternal county of residence at the time of delivery. Pollutants examined included particulate matter with aerodynamic diameter < or = 10 and < or = 2.5 microm (PM10 and PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3). We applied a linear model with birth weight as a continuous variable. The model was adjusted for known risk factors and region. We assessed pollutant effects by trimester to identify biological exposure window of concern, and explored interaction due to race/ethnicity. An interquartile increase in ambient pollutant concentrations of SO2 and O3 was associated with a 4.99-g (95% confidence interval [CI], 1.87-8.11) and 2. 72-g (95% CI, 1.11-4.33) decrease in birth weight, respectively. Lower birth weight was associated with exposure to O3 in the first and second trimester; whereas results were not significant for other pollutants by trimester A positive association was exhibited for PM2.5 in the first trimester. Effects estimates for PM10 and PM2.5 were inconsistent across race/ethnic groups. Current ambient air pollution levels may be increasing the risk of lower birth weight for some pollutants. These risks may be increased for certain racial/ethnic groups. Additional research including consideration of improved methodology is needed to investigate these findings. Future studies should examine the influence of residual confounding.

Effect of high parity on occurrence of some fetal growth indices: a cohort study

The objective of this retrospective cohort study was to explore the potential causal relation between parity and fetal growth indices, including low birth weight (LBW), macrosomia, and prematurity. The study was nested on a community trial in a city in Oman. The study analyzed 1939 pregnancies among 479 participants. Of these, 944 pregnancies (48.7%) were high parity (≥5). Obtained newborns with outcomes of interest were as follows: 191 LBW, 34 macrosomic, and 69 premature. Associations were measured using multilevel logistic regression modeling. Compared to low parity (LP, defined as <5), high parity was found to be associated with less risk of LBW (relative risk [RR] = 0.76; 95% confidence interval [CI]: 0.44–1.1) and prematurity (RR = 0.82; 95% CI: 0.54–1.27), but greater risk of macrosomia (RR = 1.8; 95% CI: 1.2–2.4). This study provides evidence that with increasing parity, risks of LBW and prematurity decrease, while risk of macrosomia increases.

A citywide smoking ban reduced maternal smoking and risk for preterm births: a Colorado natural experiment

BACKGROUND

Few reports exist on the association of a public smoking ban with fetal outcomes and maternal smoking in the United States. We sought to evaluate the effect of a citywide smoking ban in comparison to a like municipality with no such ban in Colorado on maternal smoking and subsequent fetal birth outcomes.

METHODS

A citywide smoking ban in Colorado provided a natural experiment. The experimental citywide smoking ban site was implemented in Pueblo, Colorado. A comparison community was chosen that had no smoking ban, El Paso County, with similar characteristics of population, size, and geography. The two sites served as their own controls, as each had a preban and postban retrospective observation period: preban was April 1, 2001, to July 1, 2003; postban was April 1, 2004, to July 1, 2006. Outcomes were maternal smoking (self-report), low birth weight (LBW) (defined as <2500 g or as <3000 g), and preterm births (<37 weeks gestation) in singleton births from mothers residing in these cities and reported to the State Department of Public Health. A difference-in-differences estimator was used to account for site and temporal trends in multivariate models.

RESULTS

Compared to El Paso County preban, the odds of maternal smoking and preterm births were, respectively, 38% (p<0.05) and 23% (p<0.05) lower in Pueblo. The odds for LBW births decreased by 8% for <3000 g and increased by 8.4% for <2500 g; however, neither was significant.

CONCLUSIONS

This is the first evidence in the United States that population-level intervention using a smoking ban improved maternal and fetal outcomes, measured as maternal smoking and preterm births.

Validity and reproducibility of a semi-quantitative food frequency questionnaire for use among Portuguese pregnant women

This study aimed to evaluate the validity and reproducibility of a semi-quantitative food frequency questionnaire (FFQ) to estimate nutrient intake among Portuguese pregnant women. A sample of 101 pregnant women completed a 3-day food diary (FD) in each pregnancy trimester (reference method) and an interviewer-administered FFQ in the immediate post-partum period. Ranking women according to their usual intake showed that, on average, 65% were classified into the same +/-1 quintile and 2.4% into opposite quintiles by the two methods. Energy-adjusted and de-attenuated correlation coefficients ranged from 0.20 (protein) to 0.58 (riboflavin). Similar results were obtained when the FFQ was compared to each trimester-specific FD. To assess the FFQ reproducibility, 70 women in their third pregnancy trimester were interviewed twice within a 2-week interval. The level of agreement was high, with > or = 75% of the participants being classified into the same +/-1 quintile by the two administrations for 13 of the 15 nutrients examined. A review of the published literature revealed that this is the first FFQ to take the whole pregnancy as its reference time window. Our findings showed that a single administration of this FFQ in the immediate post-partum period is a valid tool to rank Portuguese pregnant women according to their intakes.

Assessing exposure metrics for PM and birth weight models

The link between air pollution exposure and adverse birth outcomes is of public health concern due to the relationship between poor pregnancy outcomes and the onset of childhood and adult diseases. As personal exposure measurements are difficult and expensive to obtain, proximate measures of air pollution exposure are traditionally used. We explored how different air pollution exposure metrics affect birth weight regression models. We examined the effect of maternal exposure to ambient levels of particulate matter <10, <2.5 mum in aerodynamic diameter (PM(10), PM(2.5)) on birth weight among infants in North Carolina. We linked maternal residence to the closest monitor during pregnancy for 2000-2002 (n=350,754). County-level averages of air pollution concentrations were estimated for the entire pregnancy and each trimester. For a finer spatially resolved metric, we calculated exposure averages for women living within 20, 10, and 5 km of a monitor. Multiple linear regression was used to determine the association between exposure and birth weight, adjusting for standard covariates. In the county-level model, an interquartile increase in PM(10) and PM(2.5) during the entire gestational period reduced the birth weight by 5.3 g (95% CI: 3.3-7.4) and 4.6 g (95% CI: 2.3-6.8), respectively. This model also showed a reduction in birth weight for PM(10) (7.1 g, 95% CI: 1.0-13.2) and PM(2.5) (10.4 g, 95% CI: 6.4-14.4) during the third trimester. Proximity models for 20, 10, and 5 km distances showed results similar to the county-level models. County-level models assume that exposure is spatially homogeneous over a larger surface area than proximity models. Sensitivity analysis showed that at varying spatial resolutions, there is still a stable and negative association between air pollution and birth weight, despite North Carolina's consistent attainment of federal air quality standards.

Ambient air pollution exposure, residential mobility and term birth weight in Oslo, Norway

Environmental exposure during pregnancy may have lifelong health consequences for the offspring and some studies have association between maternal exposure to air pollution during pregnancy and offspring's birth weight. However, many of these studies do not take into account small-scale variations in exposure, residential mobility, and work addresses during pregnancy. We used information from the National Birth Registry of Norway to examine associations between ambient environmental exposure such as air pollution and temperature, and offspring's birth weight taking advantage of information on migration history and work address in a large population-based cohort. A dispersion model was used to estimate ambient air pollution levels at all residential addresses and work addresses for a total of 25,229 pregnancies between 1999 and 2002 in Oslo, Norway. Ambient exposure to traffic pollution for the entire pregnancy was associated with a reduction in term birth weight in crude analyzes when comparing children of the highest and lowest exposed mothers. No evidence for an association between exposure to traffic pollution at home and work addresses and term birth weight after adjustment for covariates known to influence birth weight during pregnancy. After stratification, small statistically non-significant reductions were present but only for multiparious mothers. This group also had less residential mobility and less employment during pregnancy. The overall findings suggest no clear association between term birth weight and traffic pollution exposure during pregnancy. However, mobility patterns could introduce possible confounding when examining small-scale variations in exposure by using addresses. This could be of importance in future studies.

Population-attributable risk of low birthweight related to PM10 pollution in seven Korean cities

To understand the preventable fraction of low birthweight (LBW) deliveries due to maternal exposure to air pollution during pregnancy in Korea, it is important to quantify the population-attributable risk (PAR). Thus, we investigated the association between maternal exposure to air pollution during pregnancy and LBW, and calculated the PAR for air pollution and LBW in seven Korean cities. We used birth records from the Korean National Birth Register for 2004. A geographic information system and kriging methods were used to construct exposure models. Associations between air pollution and LBW were evaluated using univariable and multivariable logistic regression, and the PAR for LBW due to air pollution was calculated. Of 177 660 full-term singleton births, 1.4% were LBW. When only spatial variation of air pollution was considered in each city, the adjusted odds ratios unit of particulate matter <10 microm in diameter (PM(10)) for LBW were 1.08 [95% confidence interval [CI] 0.99, 1.18] in Seoul, 1.24 [95% CI 1.02, 1.52] in Pusan, 1.19 [95% CI 1.04, 1.37] in Daegu, 1.12 [95% CI 0.98, 1.28] in Incheon, 1.22 [95% CI 0.98, 1.52] in Kwangju, 1.05 [95% CI 1.00, 1.11] in Daejeon and 1.19 [95% CI 1.03, 1.38] in Ulsan. The PARs for LBW attributable to maternal PM(10) exposure during pregnancy were 7%, 19%, 16%, 11%, 18%, 5% and 16% respectively. Because a large proportion of pregnant women in Korea are exposed to PM(10)--which is associated with LBW--a substantial proportion of LBW could be prevented in Korea if air pollution was reduced.

Secular trends in excess fetal and infant mortality using perinatal periods of risk analysis

Perinatal periods of risk (PPOR) provide an alternative analytical approach to studying infant mortality. Results can be used to focus community activities to improve infant and maternal health. This article demonstrates the use of PPOR to monitor trends in excess fetal and infant mortality related to disparities associated with race and ethnicity in Kansas City, MO (KC). Based on a comparison of PPOR analyses for 1996-2000 and 2001-2005, there was a 30% reduction in excess fetal and infant mortality in Kansas City and reductions for both non-Hispanic blacks (17%) and non-Hispanic whites (66.7%). However, the disparity ratio for excess mortality rates between non-Hispanic blacks and non-Hispanic whites nearly doubled. Prematurity, the most frequent cause of infant mortality in Kansas City during 2001-2005 accounted for 42.5% of the infant deaths. Being a teenage mother; having less than a high-school education; being unmarried; having an unintended pregnancy; being obese preconceptually; being diabetic; using substances such as tobacco or drugs during pregnancy; receiving late, inadequate or intermediate amounts of prenatal care; having a multifetal pregnancy; having a primary elective cesarean section; delivering a preterm infant or having a male infant; and being enrolled in Medicaid all increased the risk of infant death.

Fetal growth restriction is related to placental levels of cadmium, lead and arsenic but not with antioxidant activities

The objectives of this study were: to measure some essential metals and toxicants in placentas of mothers delivering neonates with fetal growth restriction, and to establish potential associations between environmental adverse stimulus and antioxidant protective mechanisms. Placentas of 20 mothers delivering neonates with low birth weight (<2500g) and normal birth weight (>3000g) at term were collected. Placental concentration of zinc, mercury, selenium and arsenic were measured by Instrumental Neutron Activation Analysis (INAA), and iron, copper, cadmium and lead by Atomic Absorption Spectrometry (AAS). Total glutathione, lipid peroxidation, total antioxidant activity and antioxidant enzyme activities (superoxide dismutase and glutathione peroxidase) were determined spectrophotometrically. Results showed reduced iron levels and increased concentrations of cadmium, lead and arsenic in placentas of mothers delivering low birth weight neonates, but not differences in oxidative stress parameters or antioxidant enzymatic activities, suggesting a relationship between low birth weight and placental concentration of cadmium, arsenic and lead.

A life course of adiposity and dementia

Adiposity, commonly measured as body mass index (BMI), may influence or be influenced by brain structures and functions involved in dementia processes. Adipose tissue changes in degree and intensity over the lifespan, and has been shown to influence brain development in relationship to early and late measures of cognitive function, intelligence, and disorders of cognition such as dementia. A lower BMI is associated with prevalent dementia, potentially due to underlying brain pathologies and correspondingly greater rates of BMI or weight decline observed during the years immediately preceding clinical dementia onset. However, high BMI during mid-life or at least approximately 5-10 years preceding clinical dementia onset may increase risk. The interplay of adiposity and the brain occurring over the course of the lifespan will be discussed in relationship to developmental origins, mid-life sequelae, disruptions in brain structure and function, and late-life changes in cognition and dementia. Characterizing the life course of adiposity among those who do and do not become demented enhances understanding of biological underpinnings relevant for understanding the etiologies of both dementia and obesity and their co-existence.

Improving perinatal health: a novel approach to improve community and adult health

Recent trends of increasing infant morbidity and mortality are inconsistent with this nation's vision of advances in adult quality of life and longevity. Infant mortality and weight at birth are important predictors of the health of a society, making these findings all the more disturbing. Infant morbidity could be a reflection or alternatively, a harbinger of increasing national rates of obesity, diabetes mellitus, community violence and widening economic disparities. This paper presents the linkage between perinatal health and adult health using infant morbidities (infant mortality, low birthweight, prematurity) as examples. Infant morbidities/mortalities are social problems with health-care consequences. All social classes suffer the results of poor infant health. Improving perinatal health can improve the health of a community in a cyclic fashion. We propose that improving the health of reproductive age women and infants; will result in a reduction in the incidence of severe/chronic and costly adult health outcomes.

The role of beta-cell dysfunction in the cardiometabolic syndrome

The regulation of blood glucose levels involves a finely tuned relationship between insulin sensitivity, hepatic glucose output, and production of insulin. The cardiometabolic syndrome includes in its definition criteria a disturbance of normal glucose tolerance and implies development of both insulin resistance and beta-cell dysfunction. There is now abundant evidence pointing toward a central role of dysregulation of the beta-cell function and mass in the development of impaired glucose tolerance. Mechanisms implicated in beta-cell dysfunction include genetic abnormalities, prenatal and early postnatal insults, and environmental events along with obesity, dyslipidemia-lipotoxicity, glucotoxicity, oxidative stress, chronic low-grade inflammation, amyloid deposition, and activation of the local renin-angiotensin system. Novel therapeutic characteristics of known medications such as metformin, thiazolidinediones, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and novel medications such as exendin-4 promise encouraging possibilities to battle against the cardiometabolic syndrome and the future development of cardiovascular disease.

Values and beliefs about consequences related to smoking among pregnant and non-pregnant women

The purpose of the study was to test a model based on the product of value and belief, called expected utility (EU), on the addictive behaviour of smoking. A total of 40 pregnant and 40 non-pregnant women over a period of 2 weeks performed judgements on values and beliefs about consequences related to smoking for the conditions of continuing and stopping smoking. There were no differences between pregnant and non-pregnant women in the EU of smoking. Differences in expected utility between the conditions of continuing and stopping smoking were larger for health consequences compared with psychological and social consequences and consequences related to pregnancy. Expected utility gives a good description of judgements over time. Values as well as beliefs related to health consequences should be stressed in smoking cessation programmes, especially among pregnant women.

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.

Detection and clinical manifestation of placental malaria in southern Ghana

Background

Plasmodium falciparum can be detected by microscopy, histidine-rich-protein-2 (HRP2) capture test or PCR but the respective clinical relevance of the thereby diagnosed infections in pregnant women is not well established.

Methods

In a cross-sectional, year-round study among 839 delivering women in Agogo, Ghana, P. falciparum was screened for in both, peripheral and placental blood samples, and associations with maternal anaemia, low birth weight (LBW) and preterm delivery (PD) were analysed.

Results

In peripheral blood, P. falciparum was observed in 19%, 34%, and 53% by microscopy, HRP2 test, and PCR, respectively. For placental samples, these figures were 35%, 41%, and 59%. Irrespective of diagnostic tool, P. falciparum infection increased the risk of anaemia. Positive peripheral blood results of microscopy and PCR were not associated with LBW or PD. In contrast, the HRP2 test performed well in identifying women at increased risk of poor pregnancy outcome, particularly in case of a negative peripheral blood film. Adjusting for age, parity, and antenatal visits, placental HRP2 was the only marker of infection associated with LBW (adjusted odds ratio (aOR), 1.5 (95%CI, 1.0–2.2)) and, at borderline statistical significance, PD (aOR, 1.4 (1.0–2.1)) in addition to anaemia (aOR, 2.3 (1.7–3.2)). Likewise, HRP2 in peripheral blood of seemingly aparasitaemic women was associated with PD (aOR, 1.7 (1.0–2.7)) and anaemia (aOR, 2.1 (1.4–3.2)).

Conclusion

Peripheral blood film microscopy not only underestimates placental malaria. In this highly endemic setting, it also fails to identify malaria as a cause of foetal impairment. Sub-microscopic infections detected by a HRP2 test in seemingly aparasitaemic women increase the risks of anaemia and PD. These findings indicate that the burden of malaria in pregnancy may be even larger than thought and accentuate the need for effective anti-malarial interventions in pregnancy.

Deal in the womb: Fetal opiates, parent-offspring conflict, and the future of midwifery

This paper argues that parent-offspring conflict is mediated by placental beta-endorphins in placental mammals, i.e., foetuses make their mothers endorphin-dependent then manipulate them to increase nutrient allocation to the placenta. This hypothesis predicts that: (1) anatomic position of endorphin production should mirror its presumed role in fetal-maternal conflict; (2) endorphin levels should co-vary positively with nutrient carrying capacity of maternal blood system; (3) postpartum psychological symptoms (postpartum blues, depression and psychosis) in humans are side-effects of this mechanism that can be interpreted as endorphin-deprivation symptoms; (4) shortly after parturition, placentophagia could play an adaptive role in decreasing the negative side-effects of fetal manipulation; (5) later, breast-feeding induced endorphin excretion of the maternal pituitary saves mother from further deprivation symptoms. Finally, whatever the molecular mechanism of fetal manipulation is, widespread and intense medical care (such as caesarean section and use of antidepressants) affects the present and future evolution of mother-foetus conflict in the human species (and also in domestic animals) to increase 'fetal aggressiveness' and thus technology-dependency of reproduction.