Probability Of Low Birth Weight Research Articles

Association between serum estradiol level on the human chorionic gonadotrophin administration day and clinical outcome.

Background:Estradiol, as an important hormone in follicular development and endometrial receptivity, is closely related to clinical outcomes of fresh in vitro fertilization embryo transfer (IVF-ET) cycles. The aim of this retrospective study was to evaluate the association between elevated serum estradiol (E2) levels on the day of human chorionic gonadotrophin (hCG) administration and IVF-ET pregnancy and birth outcomes.Methods:A total of 1771 infertile patients with their first fresh IVF-ET cycles were analyzed retrospectively between January 2011 and January 2016 in Peking University First Hospital. Patients were categorized by serum E2 levels on the day of hCG administration into six groups: group 1 (serum E2 levels ≤ 1000 pg/mL, n = 205), group 2 (serum E2 levels 1001–2000 pg/mL, n = 457), group 3 (serum E2 levels 2001–3000 pg/mL, n = 425), group 4 (serum E2 levels 3001–4000 pg/mL, n = 310), group 5 (serum E2 levels 4001–5000 pg/mL, n = 237), and group 6 (serum E2 levels > 5000 pg/mL, n = 137). The retrieved oocyte and MII oocyte numbers and implantation and clinical pregnancy rates of the groups were compared as the first objective of the study. For the 360 women with singleton births among all patients, the area under the corresponding receiver operating characteristic curve (ROC curve) was calculated to assess the predictive value of the E2 change for the probability of low birth weight (LBW) infants as the second objective.Results:The retrieved oocyte and MII oocyte numbers and implantation and clinical pregnancy rates gradually increased from groups 1 to 5 but decreased in group 6. The parameters of group 1 were statistically worse than those of the other groups, from group 2 to group 6 (the number of retrieved oocytes, t = 13.096, t = 23.307, t = 23.086, t = 26.376, t = 19.636, P < 0.003; the number of retrieved MII oocytes, t = 10.856, t = 20.868, t = 21.874, t = 23.374, t = 19.092, P < 0.003; the implantation rate, χ2 = 12.179, χ2 = 22.239, χ2 = 23.993, χ2 = 23.344, χ2 = 16.758, P < 0.003; the clinical pregnancy rate, χ2 = 16.415, χ2 = 28.074, χ2 = 35.387, χ2 = 37.025, χ2 = 24.590, P < 0.003). ROC analysis revealed that when a serum peak E2 of 3148 pg/mL was used to predict LBW.Conclusions:The results indicate that serum E2 levels have a concentration-dependent effect on clinical outcomes. The optimal range of the E2 level during a fresh IVF-ET cycle is 1000 to 3148 pg/mL.

Effects of State-Level Earned Income Tax Credit Laws on Birth Outcomes by Race and Ethnicity.

Purpose: Health disparities persist in birth outcomes by mother's income, education, and race in the United States. Disadvantaged mothers may experience benefit from supplements to family income, such as the earned income tax credit (EITC). We examined the effects of state-level EITCs on birth outcomes among women with a high school education or less, stratified by race and ethnicity.Methods: A quasi-experimental multistate and multiyear difference-in-differences design is used to assess effects of the presence and generosity of 23 state-level EITC laws on birth outcomes from 1994 to 2013. The methods utilized the U.S. National Vital Statistics System birth data for the outcomes: birth weight, probability of low birth weight (LBW; <2500 g), and gestation weeks.Results: Across all subgroups, any level of state EITC is associated with better birth outcomes with the largest effects seen among states with more generous EITCs. Black mothers experience larger percentage point reductions in the probability of LBW and increases in gestation duration. Among mothers with a high school education or less, results translate into 3760 fewer LBW babies with black mothers and 8364 fewer LBW babies with white mothers per year at the most generous state EITC level (i.e., 10% or more of federal and refundable). Hispanic and non-Hispanic mothers display relatively similar effects.Conclusions: The EITC at the federal and state level is an effective policy tool to reduce poverty and improve birth outcomes across racial and ethnic subgroups. Given the historically higher risk among black mothers, state-level EITC expansions offer one policy option to address this persistent health disparity.

Risk Factors Associated with Low Birth Weight

Neonatal deaths are associated with preterm birth complications. Preterm birth is also related to low birth weight (LBW), which can have multiple causes. The aim of this study was to analyze the risk factors associated with LBW. This was a cross-sectional study held in Bulu Primary Health Care, Temanggung, Central Java, Indonesia. The sample size required for this study was 69 based on the Slovin formula. Data were collected using questionnaires and semi-quantitative FFQ forms. Data on infant birth weight was taken from midwives’ delivery cohort records. Mid upper arm circumference (MUAC), hemoglobin level, blood pressure, maternal age, parity, nutritional intake, and serum transferrin receptor data were taken from the infant’s mother using a MUAC tape, automatic blood pressure monitor and blood laboratory analysis by Prodia. Data analysis procedures were carried out with quantitative methods. Descriptive statistics were analyzed as means and standard deviations. Inferential statistics used the chi-square test for bivariate analysis and binary logistic regression for multivariate analysis. The results of this study showed that mean infant birth weight was 2917.68 ± 374.673 kg. Inferential analysis showed that MUAC and pregnancy at a risky age are significant risk factors associated with LBW, while serum transferrin receptor levels, anemia, parity, energy and protein consumption levels, and systolic and diastolic blood pressure are nonsignificant risk factors. The probability of LBW in pregnant women with LILA under 23.5 cm and pregnancy at a risky age is 68.9%.

Effects of health insurance on birth weight in Mexico.

This paper estimates the effect of mother's insurance coverage on neonatal outcomes in Mexico using hospital-based administrative data. Using an instrumental variable approach to identify the causal effects of health insurance on infant health, we find that mother's insurance coverage has positive impacts on neonatal outcomes. Children born to insured mothers weighed 108g higher and had reduced probability of low birth weight by 7.5 percentage points. These effects appear to be stronger for mothers with higher levels of education and in municipalities with a higher development index. Findings indicate that expanding insurance coverage could be helpful in improving neonatal outcomes in resource-constrained countries.

Deworming During Pregnancy and Birth Outcomes

One third of infants born in India are of low birth weight (<2.5 kilograms), leading to a higher prevalence of child malnutrition. These infants are at risk of not only short term but also long term adverse health outcomes. In India, maternal anemia is one of the major concerns in low birth weight status and perinatal mortality. Intestinal parasitic infections like hookworm can cause and increase iron deficient anemia among mothers. These infections can reduce the effect of iron supplementation during pregnancy. This, in turn, can lead to low birth weight. The current study examines the role of deworming during pregnancy for birth outcomes, in particular, determining low birth weight. Data from the latest National Family Health Survey (conducted 2005–06 and released in 2008) is used for this analysis; NFHS is the Indian component of the Measure Demographic Health survey project. Using a nationwide sample of mothers and infants (n = 17,117), a matching estimation was done to assess the effect of intake of deworming drugs during pregnancy on infant’s birth weight, after controlling for various socio-demographic characteristics and the quality of available water sources and water treatment by the households. The study found that deworming during pregnancy both increased the birth weight of the infant as well as decreased the probability of low birth weight. The average increase in birth weight was estimated to be around 66 grams and the probability of low birth weight, was on average, reduced by 2.2 percentage points if deworming drugs were administered during pregnancy. This leads to the conclusion that a low cost intervention such as deworming should be considered in antenatal care packages, particularly in regions of India where helminthic infection is endemic. Apart from birth weight, several other benefits could occur from deworming during pregnancy given the pathway through Iron Deficiency Anemia (IDA).

Pre-pregnancy body mass index, gestational weight gain and adverse birth outcomes: some evidence from Italy.

Overweight and obese women present an increased risk of poor maternal and child health outcomes. The aim of this paper is to analyze the joint effects of pre-pregnancy body mass index and inadequate gestational weight gain on birth weight and gestational age in an Italian sample of pregnant women. Data were obtained from a sample of about 2,000 pregnant women at the University Teaching Hospital of Perugia University (Italy) in 2013. We used the revised classification proposed by Institute of Medicine to identify gestational weight gains considered as appropriate. Logistic regression models were used to estimate the adjusted odds-ratios of women belonging to any BMI class different from normal (used as the reference category) and of women who increased their weight by an amount smaller or greater than normal, controlling for a large set of observable confounders. Higher probability of low birth weight was associated with both obesity (OR = 1.9124, s.e. = 0.526) and less than normal weight gains (OR = 2.3614, s.e. = 0.388). The probability of fetal macrosomia was found to be positively associated with more than normal weight increases (OR = 2.6232, s.e. = 0.465). Pre-term deliveries were associated with less than normal gestational weight gains (OR 1.7338, s.e. = 0.320). Overweight and obesity represent a big issue for public health. In particular, weight management during pregnancy and pre-pregnancy could determine negative health outcomes in newborns. In our study we found that inadequate weight variations during pregnancy, according to the Classification of the Institute of Medicine, negatively influence health conditions at birth. Stronger initiatives, especially in terms of midwifery, nurse training and informative policies should be adopted by policy makers.

Risk factors for low birth weight according to the multiple logistic regression model. A retrospective cohort study in José María Morelos municipality, Quintana Roo, Mexico.

Low birth weight has been an enigma for science over time. There have been many researches on its causes and its effects. Low birth weight is an indicator that predicts the probability of a child surviving. In fact, there is an exponential relationship between weight deficit, gestational age, and perinatal mortality. Multiple logistic regression is one of the most expressive and versatile statistical instruments available for the analysis of data in both clinical and epidemiology settings, as well as in public health. To assess in a multivariate fashion the importance of 17 independent variables in low birth weight (dependent variable) of children born in the Mayan municipality of José María Morelos, Quintana Roo, Mexico. Analytical observational epidemiological cohort study with retrospective temporality. Births that met the inclusion criteria occurred in the "Hospital Integral Jose Maria Morelos" of the Ministry of Health corresponding to the Maya municipality of Jose Maria Morelos during the period from August 1, 2014 to July 31, 2015. The total number of newborns recorded was 1,147; 84 of which (7.32%) had low birth weight. To estimate the independent association between the explanatory variables (potential risk factors) and the response variable, a multiple logistic regression analysis was performed using the IBM SPSS Statistics 22 software. In ascending numerical order values of odds ratio > 1 indicated the positive contribution of explanatory variables or possible risk factors: "unmarried" marital status (1.076, 95% confidence interval: 0.550 to 2.104); age at menarche ≤ 12 years (1.08, 95% confidence interval: 0.64 to 1.84); history of abortion(s) (1.14, 95% confidence interval: 0.44 to 2.93); maternal weight < 50 kg (1.51, 95% confidence interval: 0.83 to 2.76); number of prenatal consultations ≤ 5 (1.86, 95% confidence interval: 0.94 to 3.66); maternal age ≥ 36 years (3.5, 95% confidence interval: 0.40 to 30.47); maternal age ≤ 19 years (3.59, 95% confidence interval: 0.43 to 29.87); number of deliveries = 1 (3.86, 95% confidence interval: 0.33 to 44.85); personal pathological history (4.78, 95% confidence interval: 2.16 to 10.59); pathological obstetric history (5.01, 95% confidence interval: 1.66 to 15.18); maternal height < 150 cm (5.16, 95% confidence interval: 3.08 to 8.65); number of births ≥ 5 (5.99, 95% confidence interval: 0.51 to 69.99); and smoking (15.63, 95% confidence interval: 1.07 to 227.97). Four of the independent variables (personal pathological history, obstetric pathological history, maternal stature <150 centimeters and smoking) showed a significant positive contribution, thus they can be considered as clear risk factors for low birth weight. The use of the logistic regression model in the Mayan municipality of José María Morelos, will allow estimating the probability of low birth weight for each pregnant woman in the future, which will be useful for the health authorities of the region.

Advanced Maternal Age and the Risk of Low Birth Weight and Preterm Delivery: a Within-Family Analysis Using Finnish Population Registers.

Advanced maternal age at birth is considered a major risk factor for birth outcomes. It is unclear to what extent this association is confounded by maternal characteristics. To test whether advanced maternal age at birth independently increases the risk of low birth weight (<2,500 g) and preterm birth (<37 weeks’ gestation), we compared between-family models (children born to different mothers at different ages) with within-family models (children born to the same mother at different ages). The latter procedure reduces confounding by unobserved parental characteristics that are shared by siblings. We used Finnish population registers, including 124,098 children born during 1987–2000. When compared with maternal ages 25–29 years in between-family models, maternal ages of 35–39 years and ≥40 years were associated with percentage increases of 1.1 points (95% confidence intervals: 0.8, 1.4) and 2.2 points (95% confidence intervals: 1.4, 2.9), respectively, in the probability of low birth weight. The associations are similar for the risk of preterm delivery. In within-family models, the relationship between advanced maternal age and low birth weight or preterm birth is statistically and substantively negligible. In Finland, advanced maternal age is not independently associated with the risk of low birth weight or preterm delivery among mothers who have had at least 2 live births.

Semiparametric Multinomial Ordinal Model to Analyze Spatial Patterns of Child Birth Weight in Nigeria.

Background: Birth weight is an important health parameter for obstetricians and gynaecologists. It is a good health indicator of a child-bearing mother and a strong predictor of infant morbidity and mortality. Methods: This paper utilizes data on 28,647 children born between 2003–2008 obtained from the 2008 Nigeria Demographic and Health Survey (NDHS). For a simple epidemiological convenience, the occurrence of a newborn weight can intuitively be considered to be categorical in nature and the thresholds can be put on a continuous scale. In survey reporting, the mothers frequently estimate their infant’s birth weight and make a classification in ordinal category (low, normal, large) instead of actual birth weight. The study fits a multinomial regression model to analyze the relationships between the polytomous response and different kind of covariates in a unified manner. We estimate the fixed effects of bio-social covariates parametrically and the non-linear effect modeled using P-spline. The spatial component was modeled using conditional autoregressive error. A penalized maximum likelihood estimation was performed to estimate the model parameters. Results: We found risk factors that are positively associated with low birth weight, which include multiple birth, short birth interval, death of sibling, childhood diarrhea, fever, mother’s smoking, firewood/dung cooking and poor household. Results further showed that iron syrup supplementation, antenatal attendance, mother literacy and household wealth had significant association with low probability of low birth weight. The finding also showed spatial patterns, which are not captured by the underlying determinants, and we produced probability predictive maps of the spatial residual effects. Conclusions: In addition to the statistical relevance of our method, the generated spatial maps identify highly endemic areas of low birth weight that can assist government agency to channel scarce health resources. A comprehensive approach which institutes a combination of interventions to improve the overall health care of the women is needed.

It’s Just a Game

Previous studies have explored the effect of earthquakes and terrorist attacks on birth outcomes. These events are unexpected and obvious sources of distress, but could affect fetal health through multiple channels. Using data from the National Vital Statistics System for the period 1969–2004, we estimate the relationship between prenatal exposure to the Super Bowl and low birth weight. Although sporting events can elicit intense emotions, they do not pollute the environment or threaten viewers with direct physical harm. We find that Super Bowl exposure is associated with a small, but precisely estimated, increase in the probability of low birth weight.

A simple recipe: The effect of a prenatal nutrition program on child health at birth

We study the impact of a Canadian prenatal nutrition program on child health at birth. The objective of the “oeuf-lait-orange” (eggs–milk–oranges) (OLO) program is to reduce the incidence of prematurity and low birth weight by providing a specific food basket and nutritional guidance to pregnant women in situations of poverty. Our identification strategy exploits exogenous variations in access to the program caused by the progressive implementation of the program. Using detailed administrative birth records for over 1.5 million newborns, we find that the program significantly increased the birth weight of treated children by 69.8g and reduced the probability of low birth weight by 3.6 percentage points. W also find that prematurity decreased by 2.2 percentage points and gestation increased by 1.5days, but these effects are generally not significant. While the cost of the program is equivalent to the comparable United States Supplemental Nutrition Program for Women, Infants and Children (WIC), the food basket is simpler and the gains on birth weight are larger.

The Impact of WIC on Birth Outcomes: New Evidence from South Carolina.

Objectives To investigate the impact of the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) on a variety of infant health outcomes using recent South Carolina Vital Statistics data (2004-2012). Methods To account for non-random WIC participation, the study relies on a maternal fixed effects estimation, due to the availability of unique maternally linked data. Results The results indicate that WIC participation is associated with an increase in birth weight and length of gestation, decrease in the probability of low birth weight, prematurity, and Neonatal Intensive Care Unit admission. Additionally, addressing gestational bias and accounting for the length of gestation, WIC participation is associated with a decrease in the probability of delivering a low weight infant and a small for gestational age infant among black mothers. Conclusions for Practice Accounting for non-random program participation, the study documents a large improvement in birth outcomes among infants of WIC participating mothers. Even in the context of somewhat restrictive gestation-adjusted specification, the positive impact of WIC remains within the subsample of black mothers.

Immigration policy and birth weight: Positive externalities in Italian law

A decade ago, the political party of the Italian center-right voted a law restricting immigration. The law became effective in early 2005, when the Italian parliament approved the decree for its application, but one of its articles, granting amnesty for illegal immigrant workers, became immediately effective in July 2002. As a result, 650,000 immigrants were granted the status of foreign nationals in Italy. In this paper, we examine whether the increase in the prevalence of “regular immigrants” has led to an improvement in health outcomes of babies born to migrant women, measured in terms of birth weight. Two hitherto unexploited birth sample surveys published by Italian Institute of Statistics were used for this study. Our estimates show that regularized immigration reduced the probability of low birth weight.

Environmental Health Risks and Housing Values: Evidence from 1,600 Toxic Plant Openings and Closings.

Regulatory oversight of toxic emissions from industrial plants and understanding about these emissions' impacts are in their infancy. Applying a research design based on the openings and closings of 1,600 industrial plants to rich data on housing markets and infant health, we find that: toxic air emissions affect air quality only within 1 mile of the plant; plant openings lead to 11 percent declines in housing values within 0.5 mile or a loss of about $4.25 million for these households; and a plant's operation is associated with a roughly 3 percent increase in the probability of low birthweight within 1 mile.

The Hidden Costs of War: Exposure to Armed Conflict and Birth Outcomes

Research suggests that prenatal exposure to environmental stressors has negative effects after birth. However, capturing causal effects is difficult because exposed women may be selected on unobserved factors. We use the 2006 Israel–Hezbollah war as a natural experiment and a siblings fixed-effects methodology to address unobserved selectivity by comparing exposed and unexposed births of the same mother. Findings indicate that exposure to war in early and mid-pregnancy lowers birth weight and increases the probability of low birth weight. The effect is not driven by geographic sorting, migration, or increased miscarriages. Given that birth weight predicts health, developmental, and socioeconomic outcomes, prenatal exposure to acute stress may have long-term effects over the life course.

Prenatal Stress and Low Birth Weight: Evidence from the Super Bowl

Studies have estimated the relationship between psychological stress and birth weight by exploiting natural disasters and terrorist attacks, both of which could affect fetal health through other channels. Using data from the National Vital Statistics System for the period 1969-2004, we estimate the effect of prenatal exposure to the Super Bowl on low birth weight. Although major sporting events elicit intense emotions, they do not threaten viewers with direct physical harm or limit access to prenatal care. We find that Super Bowl exposure is associated with a small, but precisely estimated, increase in the probability of low birth weight.

The Impact of WIC on Birth Outcomes: New Evidence from South Carolina Births

This study provides new evidence on the impact of the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) on a variety of infant health outcomes by using the most recent South Carolina Vital Statistics data (2004-2012). To account for non-random WIC participation, the study relies on a maternal-fixed effects estimation, due to the availability of unique maternally link data. The results indicate that WIC participation substantially decreases the probability of low birth weight, prematurity, and the probability of being admitted to a Neonatal Intensive Care Unit. Additionally, addressing gestational bias and accounting for the length of gestation, WIC participation reduces the probability of delivering a low weight infant and a small for gestation (SGA) infant by 5% among black mothers.

Transitory shocks and birth weights: Evidence from a blackout in Zanzibar

Do transitory economic shocks affect neonatal outcomes? I show that an unexpected, month-long blackout in Tanzania caused a sharp but temporary drop in work hours and earnings for workers in electricity-dependent jobs. Using records from a maternity ward, I document a reduction in birth weights for children exposed in utero to the blackout, and an increase in the probability of low birth weight. The reduction is correlated with measures of maternal exposure to the blackout. The blackout also increased fertility for teenage and first-time mothers, but selection into pregnancy cannot fully explain the drop in weights.

The impacts of air pollution on low birth weight

This study examines the impacts of air pollution on low birth weight by considering overtime variation in Korea in early 2000, when some parts of Korea experienced huge drop in air pollution due to regulation. The mother's exposure to ozone level above 0.12 ppm per hour during the first trimester increased the probability of low birth weight by 0.4 percentage point (0.08% of the sample mean). Exposure to carbon monoxide or sulphur dioxide (SO2) during the third trimester also led to a significant but modest increase in the probability of low birth weight.

Exposure to Traffic-related Air Pollution During Pregnancy and Term Low Birth Weight: Estimation of Causal Associations in a Semiparametric Model

Traffic-related air pollution is recognized as an important contributor to health problems. Epidemiologic analyses suggest that prenatal exposure to traffic-related air pollutants may be associated with adverse birth outcomes; however, there is insufficient evidence to conclude that the relation is causal. The Study of Air Pollution, Genetics and Early Life Events comprises all births to women living in 4 counties in California's San Joaquin Valley during the years 2000-2006. The probability of low birth weight among full-term infants in the population was estimated using machine learning and targeted maximum likelihood estimation for each quartile of traffic exposure during pregnancy. If everyone lived near high-volume freeways (approximated as the fourth quartile of traffic density), the estimated probability of term low birth weight would be 2.27% (95% confidence interval: 2.16, 2.38) as compared with 2.02% (95% confidence interval: 1.90, 2.12) if everyone lived near smaller local roads (first quartile of traffic density). Assessment of potentially causal associations, in the absence of arbitrary model assumptions applied to the data, should result in relatively unbiased estimates. The current results support findings from previous studies that prenatal exposure to traffic-related air pollution may adversely affect birth weight among full-term infants.