Low birth weight in newborns represents a significant indicator of the level of healthcare quality during pregnancy and the overall health status of the population. According to the WHO definition, it is a weight lower than 2 500 grams at birth. This phenomenon is considered a serious global problem because it carries a risk of both acute and long-term health complications (WHO, 2025).

Every year more than 20 million children are born with low birth weight, corresponding to roughly 15–20% of all births. International health strategies aim to reduce this share by 30% by 2025.

The occurrence of low birth weight is significantly higher in lower-income countries, where it affects roughly every sixth child, which is more than double that in developed countries. In some regions of Asia, this issue affects up to one-third of newborns. In 36 countries with a high prevalence of child stunting, the share of low birth weight ranges from 9% to 30%, with a substantial part consisting of slowed intrauterine growth (WHO, UNICEF, 2025).

Characteristics of births with low birth weight:

  • Newborns with low birth weight are live-born infants whose birth weight does not exceed 2 500 grams and who were born after the 37th completed week of gestation.
  • This indicator includes all births (live and stillbirths) where recorded birth weight is below 2 500 grams, and is expressed as a proportion of all live births with available birth weight data.

Definition of very low birth weight:

  • This category includes births (live and still) with infant birth weight below 1 500 grams, and this incidence is expressed as a percentage of all live births with documented birth weight.

Children born with a weight below the normal threshold more frequently suffer physical growth disorders and lag in cognitive development even during early developmental stages. These developmental disadvantages can negatively affect school performance, work productivity, and overall quality of life (USNA, 2025).

In adulthood, people with low birth weight show an increased risk of non-communicable diseases such as cardiovascular disorders, diabetes, and hypertension. This condition also supports the persistence of a vicious cycle of social inequalities—especially in developing and middle-income countries—where low birth weight is often associated with poverty, nutritional deficiencies, and increased morbidity.

The consequences of low birth weight are also reflected economically—they lead to higher healthcare costs, longer hospitalizations, and more frequent interruptions in parents’ work activity. Therefore, it is highly important to identify risk factors early and create effective preventive strategies aimed at reducing the incidence of this health problem (Feyisa, 2023).

Materials and methods

Low birth weight, defined as newborn weight below 2 500 grams, is a major public health problem because it is associated with increased neonatal mortality, developmental delays, and a higher risk of chronic disease in later life. Low birth weight can be due to preterm birth or intrauterine growth restriction. For this publication we selected 2 main analyses:

  • The impact of socioeconomic factors on the occurrence of low birth weight
  • The effect of maternal behavior and lifestyle on low birth weight in newborns

Impact of socioeconomic factors on the occurrence of low birth weight

Socioeconomic circumstances are a key factor influencing pregnancy progression and fetal development and are strongly correlated with low birth weight. Newborns of mothers from disadvantaged social environments are more often exposed to risks such as inadequate nutrition, limited contact with health services, chronic psychosocial stress, and living in inadequate conditions.

The etiology of low birth weight is complex and multifactorial. Key determinants include maternal age, nutritional status and body weight before conception, duration of gestation, interpregnancy intervals, reproductive history, level of formal education, presence of domestic violence during pregnancy, inadequate prenatal care, and very low socioeconomic status. Especially low maternal education, underweight (BMI < 18,5), short maternal stature (height < 145 cm), and fewer than four prenatal visits during pregnancy are considered key predictors (Kader et al., 2014).

One of the most important predictors of birth weight is maternal educational level. As maternal education increases, the probability of delivering a low-birth-weight newborn decreases. Silvestrin et al. (2020) confirmed that mothers with low or no education show the highest rate of low birth weight among their children. Higher education plays a protective role—women with better education generally have better access to health services, relevant information on pregnancy care, and adequate nutrition. By contrast, women with lower education more often display risk behaviors (e.g., smoking, drug use) and face barriers in accessing healthcare, which negatively affects fetal growth (Silvestrin et al., 2020).

Research by Alsayeeda et al. (2023) identified that factors such as low family income, partner unemployment, lack of social support, and low education level have a negative impact—both direct and mediated—on newborn birth weight. Financial strain forces women to work in harmful conditions, increasing both their health risk and risk to the fetus. Likewise, the absence of partner support in the home environment leads to increased strain and reduced psychosocial well-being, which can translate into lower birth weight.

Increased maternal education has a favorable effect on employability, income opportunities, nutritional quality, regularity of prenatal examinations, and reduction of risk behaviors such as smoking, thereby promoting optimal fetal development. These findings confirm that a higher level of education is a significant protective factor against the occurrence of low birth weight.

In conclusion, emotional and practical support from family and partner also plays an important role. Insufficient support in this regard can lead to higher stress levels, excessive physical burden, and worsening living conditions during pregnancy, which subsequently negatively affects fetal development. Conversely, good social surroundings and community support contribute to reducing the mother’s psychological burden and improving perinatal outcomes (Alsayeed et al., 2023).

Impact of maternal behavior and lifestyle on low birth weight in the newborn

Maternal nutrition during pregnancy is a fundamental factor affecting intrauterine fetal development and the probability of achieving physiological birth weight. Unbalanced diet, essential nutrient deficiencies, and the absence of qualified nutritional counseling can negatively affect fetal growth and development, thereby increasing the chances of low birth weight. This problem is particularly acute in less economically developed countries, where nutritional standards for pregnant women are often inadequate. Research findings clearly indicate that lack of dietary counseling during pregnancy, limited number of prenatal visits, nutritional deprivation, and maternal exposure to chronic stress contribute significantly to the risk of delivering a hypotrophic newborn. Among women who were not provided with professional nutritional intervention during pregnancy, more than double the probability of giving birth to a low-birth-weight infant was observed compared to those who received such support (Jamshed et al., 2020).

Fetal physiological development is primarily conditioned by the quality and quantity of nutrition received from the mother. Energy insufficiency, protein deficits, and lack of key micronutrients—including iron, vitamin A, folic acid, and vitamin B12—represent major risk factors for intrauterine growth retardation. In addition to quantitative deficiencies, the qualitative composition of the diet also needs to be considered. Excessive intake of highly processed foods, simple sugars, refined grains, saturated fats, and alcohol—especially at higher doses (more than 2–3 units per day)—has a negative effect on fetal development and can lead to reduced birth weight.

The overall health of the mother during pregnancy is inseparably linked to fetal growth parameters. Use of addictive substances such as tobacco and alcohol is among the most common preventable risk factors for low birth weight, preterm birth, and other serious perinatal complications. These risky practices are more common among women with lower socioeconomic status, who more often face concurrent exposure to multiple adverse influences, such as psychosocial stress, nutritional deficiency, and limited access to health care.

Dependence in pregnancy is also associated with adverse newborn outcomes and increased incidence of cardio-metabolic risk factors in offspring. Although not all studies clearly demonstrate a causal relationship between prenatal use of addictive substances and long-term health consequences for the child, inconsistencies may result from differences in dose, frequency, and timing of exposure.

Although global trends indicate a decline in smoking and alcohol consumption among pregnant women, tobacco smoke remains a serious health problem, especially among socially disadvantaged groups. In this population, there is also an increased likelihood of clustering of risk factors—the combined use of tobacco, alcohol, and drugs—which markedly increases health threats to both mother and fetus (Girma et al., 2019).

Discussion

Low birth weight is a serious public health problem linked to an increased risk of neonatal morbidity and mortality as well as adverse long-term effects on health in childhood and adulthood. It is a complex phenomenon driven by many determinants that can be categorized as socioeconomic and behavioral aspects. Increasingly, interest now extends beyond biological determinants to social determinants of health, including mothers’ living conditions, which strongly influence pregnancy course and fetal intrauterine growth. Factors such as socioeconomic position (e.g., education level, household economic situation, employment) and lifestyle during pregnancy (e.g., smoking, dietary habits, use of psychoactive substances, access to prenatal care) form a complex set of variables that often act synergistically.

According to the study by Mishra et al. (2021), women from lower social classes more often faced inadequate nutrition, lived in conditions with poor hygiene and sanitation, and had limited access to healthcare or nutritional supplements. These conditions negatively affect the mother’s overall health, which is a key factor for physiological fetal development and birth weight. Therefore, prevention of preterm birth and fetal growth insufficiency requires ensuring high-quality prenatal care, adequate nutrition, and sanitary conditions during pregnancy. Insufficient intake of macro- and micronutrients combined with limited access to healthcare increases the likelihood of complications, including low birth weight (Mishra et al., 2021).

Comprehensive healthcare, balanced nutrient intake, and an environment free from harmful exposures are necessary for optimal prenatal fetal development. Smoking during pregnancy remains a major risk factor for low birth weight. Poor maternal nutritional status is strongly associated with reduced fetal growth and increased neonatal mortality and morbidity. A woman’s nutritional profile before and during pregnancy is one of the main predictors of favorable pregnancy and birth outcomes. Research by Ancira-Moreno et al. (2020) showed that a deficit of essential dietary components—especially fats and proteins, which are crucial for energy needs and tissue development—can negatively affect fetal development. Anthropometric indicators such as height, weight, body mass index (BMI), and overall gestational weight gain are closely linked to birth weight. In cases of insufficient nutritional intake, BMI and gestational weight gain are reduced, representing two major predictors of birth weight (Ancira-Moreno et al. 2020).

Tobacco products have a strongly negative effect on fetal health. Active maternal smoking, as well as passive exposure to cigarette smoke—especially from a smoking partner—significantly increases the risk of low birth weight and preterm birth. Although many women conceal their smoking history, estimates suggest that up to 22.9% of pregnant smokers and 9.2% of non-smoking women of reproductive age report inaccurate tobacco exposure data. Existing evidence clearly supports a causal relationship between fetal exposure to tobacco toxins and disruption of its development, underscoring the need for prevention of both active and passive smoking to the same extent (Delcroix et al., 2023).

However, smoking is not the only negative accompanying feature of a risky lifestyle during pregnancy. Other behavioral risk factors include excessive alcohol consumption, sedentary lifestyle, and inappropriate eating patterns. These habits significantly increase the likelihood of complications such as low birth weight, preterm delivery, or intrauterine growth retardation, and should therefore be systematically included in education and prevention within prenatal care.

Alcohol consumption during pregnancy poses a serious risk that can cause significant fetal developmental damage. Ethanol and its metabolites cross the placenta and may disrupt key physiological processes, thereby affecting growth, cellular differentiation, and maturation of fetal structures. Even low to moderately high doses of alcohol have been shown to increase the risk of low birth weight, preterm delivery, growth disorders, and fetal alcohol syndrome. Alcohol impairs optimal nutrient transfer across the placenta, reduces uteroplacental blood flow, and induces oxidative stress, leading to placental tissue damage. Risk increases with frequency and amount of consumption, with so-called binge drinking (binge intake of large amounts of alcohol) having especially harmful effects (Abdallah et al., 2021).

Conclusion

Identifying and managing factors that contribute to low birth weight is a key element in protecting the health of newborns and their mothers. This indicator is closely linked to adverse health outcomes around birth and later in the child’s life. Accurate determination of birth weight plays an important role in recognizing at-risk newborns and subsequently tailoring healthcare. Reducing the incidence of low birth weight requires a holistic approach focused on improving care during pregnancy, nutritional management of expectant mothers, and timely specialist interventions. Such measures significantly contribute to better health outcomes for newborns and a healthy start to their lives.

Authors: MVDr. Martina Hrubovčák Tejová prof. MUDr. Kvetoslava Rimárová, CSc. prof. MUDr. Mgr. Erik Dorko, PhD., MPH, MBA Mgr. Simona Miškárová Mgr. Anastasiia Ostafiichuk PharmDr. Dominik Kľoc MUDr. Dana Kluková

The work is supported by KEGA 003UPJŠ-4/2024 grant Updating and innovation of the Public Health study program in the prevention of chronic non-communicable diseases and by KEGA 0010UPJŠ-4/2024 grant Implementation of multimedia technologies in teaching preventive interventions in medical and non-medical fields.

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