Socio-economic inequalities in low-birth weight, full-term babies from singleton pregnancies in Taiwan

Participation in Conditional Cash Transfer Program During Pregnancy and Birth Weight-Related Outcomes

Importance

There is limited evidence of the association of conditional cash transfers, an important strategy to reduce poverty, with prevention of adverse birth-related outcomes.

Objective

To investigate the association between receiving benefits from the Bolsa Família Program (BFP) and birth weight indicators.

Design, Setting, and Participants

This cohort study used a linked data resource, the Centro de Integracao de Dados e Conhecimentos Para Saude (CIDACS) birth cohort. All live-born singleton infants born to mothers registered in the cohort between January 2012 and December 2015 were included. Each analysis was conducted for the overall population and separately by level of education, self-reported maternal race, and number of prenatal appointments. Data were analyzed from January 3 to April 24, 2023.

Exposure

Live births of mothers who had received BFP until delivery (for a minimum of 9 months) were classified as exposed and compared with live births from mothers who did not receive the benefit prior to delivery.

Main Outcomes and Measures

Low birth weight (LBW), birth weight in grams, and small for gestational age (SGA) were evaluated. Analytical methods used included propensity score estimation, kernel matching, and weighted logistic and linear regressions. Race categories included Parda, which translates from Portuguese as "brown" and is used to denote individuals whose racial background is predominantly Black and those with multiracial or multiethnic ancestry, including European, African, and Indigenous origins.

Results

A total of 4 277 523 live births (2 085 737 females [48.8%]; 15 207 among Asian [0.4%], 334 225 among Black [7.8%], 29 115 among Indigenous [0.7%], 2 588 363 among Parda [60.5%], and 1 310 613 among White [30.6%] mothers) were assessed. BFP was associated with an increase of 17.76 g (95% CI, 16.52-19.01 g) in birth weight. Beneficiaries had an 11% lower chance of LBW (odds ratio [OR], 0.89; 95% CI, 0.88-0.90). BFP was associated with a greater decrease in odds of LBW among subgroups of mothers who attended fewer than 7 appointments (OR, 0.85; 95% CI, 0.84-0.87), were Indigenous (OR, 0.73; 95% CI, 0.61-0.88), and had 3 or less years of education (OR, 0.76; 95% CI, 0.72-0.81). There was no association between BFP and SGA, except among less educated mothers, who had a reduced risk of SGA (OR, 0.83; 95% CI, 0.79-0.88).

Conclusions and Relevance

This study found that BFP was associated with increased birth weight and reduced odds of LBW, with a greater decrease in odds of LBW among higher-risk groups. These findings suggest the importance of maintaining financial support for mothers at increased risk of birth weight-related outcomes.

Evaluating the effect of Bolsa Familia, Brazil's conditional cash transfer programme, on maternal and child health: A study protocol

BACKGROUND

Conditional Cash Transfer Programs have been developed in Latin America in response to poverty and marked social inequalities on the continent. In Brazil, the Bolsa Familia Program (BFP) was implemented to alleviate poverty and improve living conditions, health, and education for socioeconomically vulnerable populations. However, the effect of this intervention on maternal and child health is not well understood.

METHODS

We will evaluate the effect of BFP on maternal and child outcomes: 1. Birth weight; 2. Preterm birth; 3. Maternal mortality; and 4. Child growth. Dynamic retrospective cohort data from the 100 Million Brazilian Cohort (2001 to 2015) will be linked to three different databases: Live Birth Information System (2004 to 2015); Mortality Information System (2011 to 2015); and Food and Nutritional Surveillance System (2008 to 2017). The definition of exposure to the BFP varies according to the outcome studied. Those who never received the benefit until the outcome or until the end of the follow-up will be defined as not exposed. The effects of BFP on maternal and child outcomes will be estimated by a combination of propensity score-based methods and weighted logistic regressions. The analyses will be further stratified to reflect changes in the benefit entitlement before and after 2012.

DISCUSSION

Harnessing a large linked administrative cohort allows us to assess the effect of the BFP on maternal and child health, while considering a wide range of explanatory and confounding variables.

Maternal educational inequalities about adverse pregnancy outcomes observed in a rural area of a province of China during a time period (2010-2018)

BACKGROUND

The relationship between maternal education and adverse pregnancy outcomes is well documented. However, limited research has investigated maternal educational disparities in adverse pregnancy outcomes in China. This study examined maternal educational inequalities associated with adverse pregnancy outcomes in rural China.

METHODS

We conducted a population-based cohort study using participants enrolled in the National Free Preconception Health Examination Project in Yunnan province from 2010 to 2018. The primary outcome was stillbirth, and the secondary outcome was adverse pregnancy outcomes, defined as a composite event of stillbirth, preterm birth or low birth weight. The study was restricted to singleton births at 20-42 weeks' gestation. Univariate and multivariate log-binomial regression models were performed to estimate crude risk ratios (RRs) and confounding-adjusted RRs (ARRs) for stillbirth and adverse pregnancy outcomes according to maternal education level.

RESULTS

A total of 197 722 singleton births were included in the study. Compared with mid-educated women, low-educated women were at a significantly increased risk of stillbirth (ARR, 1.20; 95% CI, 1.05 to 1.38) and adverse pregnancy outcomes (ARR, 1.11; 95% CI, 1.07 to 1.16). However, the risk of stillbirth (ARR, 1.16; 95% CI, 1.01 to 1.35) was significantly higher for high-educated women compared with mid-educated women.

CONCLUSION

Compared with women with medium education level, women with lower education level were more likely to experience adverse pregnancy outcomes, including stillbirth, and women with higher education level were more likely to experience stillbirth.

Factors associated with low birth weight at term: a population-based linkage study of the 100 million Brazilian cohort

BACKGROUND

Factors associated with low birth weight at term (TLBW), a proxy for intrauterine growth restriction (IUGR), are not well-elucidated in socioeconomically vulnerable populations. This study aimed to identify the factors associated with TLBW in impoverished Brazilian women.

METHODS

Records in the 100 Million Brazilian Cohort database were linked to those in the National System of Information on Live Births (SINASC) to obtain obstetric, maternal, birth and socioeconomic data between 2001 and 2015. Multivariate logistic regression was performed to investigate associations between variables of exposure and TLBW.

RESULTS

Of 8,768,930 term live births analyzed, 3.7% presented TLBW. The highest odds of TLBW were associated with female newborns (OR: 1.49; 95% CI: 1.47-1.50), whose mothers were black (OR: 1.20; 95% CI: 1.18-1.22), had a low educational level (OR: 1.57; 95% CI: 1.53-1.62), were aged ≥35 years (OR: 1.44; 95% CI: 1.43-1.46), had a low number of prenatal care visits (OR: 2.48; 95% CI: 2.42-2.54) and were primiparous (OR: 1.62; 95% CI: 1.60-1.64). Lower odds of TLBW were found among infants whose mothers lived in the North, Northeast and Center-West regions of Brazil compared to those in the South.

CONCLUSION

Multiple aspects were associated with TLBW, highlighting the need to comprehensively examine the mechanisms underlying these factors, especially in more vulnerable Brazilian populations, in order to contribute to the elaboration of health policies and promote better conditions of life for poor and extremely poor mothers and children.

Risk factors of neonatal mortality in Iran: a systematic review

Background: Reducing neonatal mortality is an important measure to reduce the overall under-five-years' mortality. Identifying the risk factors is the first step in this regard. This study performed with the aim of determining the risk factors of the neonatal mortality in Iran. Methods: Databases of SID, MagIran, IranMedex, IronDoc and Google Scholar for the Persian resources and Scopus, Science Direct, PubMed, Ovid, EMBASE, ISI web of science and Cochrane for English resources were searched up to January 2017. The inclusion criteria were the studies analyzing at least one risk factor for neonatal mortality in Iran with a control group and multivariate regression analysis. Eight papers met the inclusion criteria. The risk factors were extracted and tabulated. Results: Of the 1713 records retrieved, 8 were eligible to include in the analysis. Preterm birth, low birth weight, smoking and addiction, and anomaly were the important risk factors of neonatal mortality in Iran. Moreover, an extended list of potential risk factors identified on most of which the evidence was controversial and insufficient. The factors categorized into modifiable and identifiable ones. Conclusion: On the modifiable risk factors, proper intervention, and on the non-modifiable ones, early detection and special care may be helpful in preventing the babies from death. Population-based studies with large sample size and multivariate analysis are needed to make clear the effect size of the identified risk factors.

Effects of recruiting midwives into family physician program on the percentage of low birth weight (LBW) infants in rural areas of Kurdistan

Background: LBW is an important factor that can affect infant mortality and represents an index of economic and social development. It is expected that an increase in the density of midwives attending family physician programs will lead to a decrease in LBW in health centers. This study aimed to compare the percentage of LBW infants before and after the implementation of the family physician program in health centers with and without an increase in midwives density.

Methods: This cross-sectional study compared the percentage of LBW infants before and after the implementation of family physician programs in rural health centers with and without changes in midwives density in Kurdistan. In this study, we included 668 mothers of 2-month-old children and administered structured interviews in 2005 and 2013. Data were analyzed using the difference-indifferences and the Matchit statistical models.

Results: The Matchit model showed a significant average percentage increase 0.08 (0.006–0.17) in LBW infants born between 2005 and 2013 in health centers where the density of midwives increased compared with those where it remained unchanged. The difference-in-differences model showed that the odds ratio of LBW infants is increased by more than twice among participants who had a history of caesarean section.

Conclusion: The results of this study showed that an increase in the density of midwives in a family physician program did not have an impact on reducing the percentage of LBW infants born between 2005 and 2013, in health centers where the density of midwives augmented compared to those where it remained unaltered; it indicated that the increase in the density of midwives alone was not efficient. On the other hand, the results of our study show an increase in the risk of infants born at a LBW due to caesarean section. It is recommended that obstetricians and gynecologists must strictly control pregnancies and avoid unnecessary termination of pregnancy

Air pollution and low birth weight in an industrialized city in Southeastern Brazil, 2003-2006

ABSTRACT: Introduction: Birth weight is an important indicator of several conditions that manifest earlier (as fetal and neonatal mortality and morbidity, inhibited growth and cognitive development) and later in life such as chronic diseases. Air pollution has been associated with adverse pregnancy outcomes. Objective: Retrospective cohort study investigated the association between low birth weight (LBW) and maternal exposure to air pollutants in Volta Redonda city, Rio de Janeiro, Brazil, from 2003 to 2006. Methods: Birth data was obtained from Brazilian Information System. Exposure information (O3, PM10, temperature and humidity) was provided by Governmental Air Quality Monitoring System. Linear and Logistic models, adjusted for sex, type of pregnancy, prenatal care, place of birth, maternal age, parity, education, congenital anomalies and weather variables were employed. Results: Low birth weight (LBW) represented 9.1% of all newborns (13,660). For an interquartile range increase in PM10 it was found OR2 ndTrimester = 1.06 (95%CI 1.02 - 1.10), OR3 rdTrimester = 1.06 (95%CI 1.02 - 1.10) and, in O3 it was found OR2 ndTrimester = 1.03 (95%CI 1.01 - 1.04), OR3 rdTrimester = 1.03 (95%CI 1.02 - 1.04). The dose-response relationship and a reduction in birth weight of 31.11 g (95%CI -56.64 - -5.58) was observed in the third trimester of pregnancy due to an interquartile increase of O3. Conclusion: This study suggests that exposures to PM10 and O3, even being below the Brazilian air quality standards, contribute to risks of low birth weight.

Prenatal care in combination with maternal educational level has a synergetic effect on the risk of neonatal low birth weight: new findings in a retrospective cohort study in Kunshan City, China

Objectives

To investigate the dose-response relationship and synergetic effect of the maternal educational level and two measures of prenatal care on neonatal low birth weight (LBW) risk.

Methods

Data were derived from the Perinatal Health Care Surveillance System (PHCSS) from January 2001 to September 2009 in Kunshan City, Jiangsu province, eastern China, which included data on 31412 women with a normal birth weight delivery and 640 women with a LBW delivery. Logistic modelling was performed to estimate the association including the joint effects with odds ratio (OR) and 95% confidence interval (CI) between the prenatal care measures and LBW risk after adjusting for the potential confounders. The dose-response relationship between the number of prenatal care visits and the risk of LBW was investigated by modeling the quantitative exposure with restricted cubic splines (RCS).

Results

There was a significant synergetic effect on the LBW risk between maternal educational attainment and the number of prenatal care visits (χ² = 4.98, P = 0.0257), whereas no significant maternal educational attainment interaction was found with the week of initiation of prenatal care after adjusting for relevant confounding factors (χ² = 2.04, P = 0.1530), and the LBW risk displayed a ‘U-shape’ curve tendency among the different number of prenatal care visits (P for nonlinearity = 0.0002) using RCS. In particular, the ORs were approaching the curve’s bottom when the women had 9 or 10 prenatal care visits. Comparing with 5 prenatal care visits, the ORs and 95%CI of LBW risk for 7, 9, 11 and ≥13 visits were 0.92 (0.82–1.03), 0.50 (0.38–0.66), 0.62 (0.47–0.82), and 0.99 (0.61–1.60), respectively.

Conclusions

Our findings suggest that appropriate prenatal care, in combination with a higher maternal educational level, can produce a protective interaction effect on LBW risk. Reasonable health resource assignment for different social statuses should be taken into account by policy-makers in developing countries.

How many low birthweight babies in low- and middle-income countries are preterm?

OBJECTIVE: To assess the prevalence of preterm birth among low birthweight babies in low and middle-income countries. METHODS: Major databases (PubMed, LILACS, Google Scholar) were searched for studies on the prevalence of term and preterm LBW babies with field work carried out after 1990 in low- and middle-income countries. Regression methods were used to model this proportion according to LBW prevalence levels. RESULTS: According to 47 studies from 27 low- and middle-income countries, approximately half of all LBW babies are preterm rather than one in three as assumed in studies previous to the 1990s. CONCLUSIONS: The estimate of a substantially higher number of LBW preterm babies has important policy implications in view of special health care needs of these infants. As for earlier projections, our findings are limited by the relative lack of population-based studies.

The case against customised birthweight standards

Customised birthweight standards are widely recognised to improve the prediction of adverse perinatal outcomes compared with conventional birthweight-for-gestational-age charts. However, their apparent benefits are more likely to have been derived from their incorporation of intrauterine-based (EFW) reference values at preterm ages than their adjustment for maternal characteristics. Although maternal characteristics are able to explain population-level differences in birthweight, they are not strong enough predictors for individual-level prediction of birthweight. With maternal characteristics accounting for only a small per cent of the total factors influencing birthweight, the best estimate of an infant's birthweight remains close to the population average, explaining the ineffectiveness of adjusting for maternal characteristics. Given that customised percentiles are also unable to distinguish between pathological and physiological influences of maternal characteristics on birthweight, customising birthweight percentiles for maternal characteristics has little justification.

Socio-economic and medical determinants of low birth weight in Iran: 20 years after establishment of a primary healthcare network

OBJECTIVE

Establishment of a primary healthcare network in Iran has provided free and universal access to primary health care. Although the health status of Iranians has improved since this network was established, the low-birthweight rate has not decreased. The objective of the present study was to describe socio-economic and medical factors related to low birth weight in the context of free and universal access to primary health care.

DESIGN

Descriptive, hospital-based prospective study.

METHODS

Data about socio-economic, reproductive and prenatal condition of 4510 live singleton births from June to October 2004 were gathered using a standard questionnaire by interview and record review. The effect of these conditions on birth weight was investigated using a logistic regression model.

RESULTS

Of 4510 newborns, 305 (6.8%) were low birth weight. Among these low-birthweight newborns, there were 159 preterm and 146 term newborns. Mothers with a primary and secondary education [odds ratio (OR) 6.83, 95% confidence interval (CI) 2.35-7.34 and OR 4.81, 95%CI 1.95-6.37, respectively], who lived with farmer and unskilled worker husbands (OR 2.52, 95%CI 1.12-4.66 and OR 2.91, 95%CI 1.35-2.52, respectively), with a birth interval of 1 year or less (OR 3.54, 95%CI 1.80-5.95) and height less than 155cm (OR 1.82, 95%CI 1.12-3.31) were more likely to have low-birthweight infants.

CONCLUSION

In the context of free and universal access to health care, it is recommended that policy makers should place more emphasis on education as it imparts knowledge and thus influences dietary habits and birth-spacing behaviour. This will lead to a better nutritional status, particularly in dealing with pregnancy, resulting in lower rates of low birth weight.