Human reproduction is a multifaceted process encompassing social, biochemical, and physical dimensions, and its success is less guaranteed than previously believed [1]. Several maternal factors can influence the health of the fetus or neonate, and assessing maternal risk factors, particularly those related to neonatal nutritional status, is crucial in reducing neonatal health risks. These factors vary by region and country, depending on socio-economic conditions and environmental factors. Bangladesh, as one of the least developed nations, faces significant challenges, including widespread malnutrition and ignorance, which predominantly affect low birth weight (LBW) infants and children [2]. Birth weight serves as a critical indicator of a country's overall health status. It is a key determinant of a newborn's survival, the likelihood of thriving in infancy, and their long-term development. As a result, increased attention is being directed towards improving birth weight distributions, particularly reducing the prevalence of LBW, as it reflects the general health of the population [3]. The World Health Assembly (WHA) defined LBW in 1976 as a birth weight below 2,500 grams. There are two primary factors influencing birth weight: the length of gestation and the fetal growth rate. A reduction in either can result in prematurity, which manifests as preterm birth or fetal growth retardation. In many developing regions, these two conditions often co-exist [4]. Preterm birth is defined as a gestational age of less than 37 completed weeks, while the term "small for gestational age" (SGA) refers to newborns whose birth weight is below the 10th percentile or more than two standard deviations lower than the expected weight for their gestational age. SGA may result from constitutional factors or pathological growth restriction, both of which increase the risk of neonatal mortality and morbidity. Globally, in 1982, of the 127 million infants born, approximately 20 million (16%) were estimated to weigh less than 2,500 grams, with over 90% of these infants born in developing countries. Asia, in particular, reported some of the highest LBW rates. India had the largest percentage at 30%, followed by Pakistan (27%), Indonesia (14%), Malaysia (10.6%), and Iran (14%) [5]. The World Health Organization (WHO) has estimated that at least 13.7 million infants are born annually with LBW at term in developing countries, accounting for 11% of all births [6]. This rate is nearly six times higher than in developed countries [7]. Additionally, a study from 1979 revealed that 20.6 million LBW infants were born, primarily in developing regions, with one-third of Indian babies born with LBW largely due to maternal undernutrition [8]. Approximately seven million LBW infants are born in India each year [9]. In Bangladesh, there is limited data on the specific risk factors associated with LBW. However, in countries with similar socio-economic, cultural, and environmental conditions, such as Pakistan, India, Malaysia, and Thailand, maternal malnutrition, lack of education, physical labor during late pregnancy, and poor economic conditions have been identified as contributing factors to LBW [5]. Given the parallels between these countries and Bangladesh, it can be inferred that similar risk factors might impact birth weight. Therefore, it is essential to investigate these factors to reduce perinatal mortality and morbidity.  This study aims to assess the effects of maternal nutritional status and socio-economic factors on the birth weight of full-term infants. Although the hospital-based nature of the study limits its ability to represent the national LBW situation, the findings can provide valuable insights for improving care for mothers and neonates at BSMMU. Additionally, this information can guide hospital planners in resource allocation for malnourished pregnant women and LBW infants.

This cross-sectional, prospective study was meticulously designed and executed within the Department of Obstetrics and Gynecology at Bangabandhu Sheikh Mujib Medical University (BSMMU) in Dhaka, Bangladesh. It spanned a comprehensive six-month period from May 2006 to October 2006. A purposive sampling approach was employed to recruit a carefully selected cohort of 200 term pregnant women admitted to the department. The selection process was rigorously aligned with predefined inclusion and exclusion criteria, ensuring both the integrity and clinical relevance of the study population.

Inclusion criteria:

• Pregnant women at term (defined as 37 to 42 completed weeks of gestation) with a known last menstrual period (LMP).

Exclusion criteria:

• Pregnant women presenting with hypertension, pre-eclampsia, eclampsia, diabetes mellitus, thyroid dysfunction, or nephritis were excluded from the study.
• Cases of major congenital fetal anomalies and multiple pregnancies were also omitted to maintain the homogeneity of the sample.

A structured questionnaire was meticulously developed and pre-tested before its administration to ensure validity and reliability. Maternal weight and height were measured following delivery, while neonatal birth weight was recorded immediately after birth. Each participant was thoroughly briefed on the study's objectives, aims, and methodologies, and informed written consent was obtained prior to their inclusion. Baseline demographic and clinical data were collected with strict adherence to confidentiality protocols. The university's institutional ethics review board granted ethical approval for the study.

Statistical Analysis

Data were systematically organized into tables and figures, supplemented with detailed explanatory notes for enhanced clarity. Statistical analysis was performed using SPSS software on a Windows platform. Continuous variables were expressed as mean±standard deviation (SD), while categorical variables were reported as frequencies and percentages, facilitating a comprehensive interpretation of the findings. Quantitative variables were compared using an unpaired t-test, and categorical variables were analyzed using the chi-square test. Statistical significance was defined as a p-value of ≤ 0.05.

The majority of participants were between 20-29 years old (75.5%), with the mean age being 24.6±4.7 years. Only a small percentage were above 35 years (3%). Regarding BMI, most participants had a normal range of 18.5-24.9 kg/m² (89%), with a small proportion being underweight (7%) or overweight (4%) with a mean of 22.04±1.32 kg/m². Parity levels were varied, with about half of the participants (50%) having 1-3 children and 46.5% being nulliparous (Table 1). The socio-economic characteristics of the participants in Table 2 revealed that most of them lived in urban areas (82%), and the majority of mothers had at least a secondary level of education (59%). A significant proportion of the participants (87.5%) were housewives, reflecting a traditional occupational distribution. Monthly family income varied, with 46.5% earning between 5001-10000 BDT, while only a small percentage earned above 20000 BDT (12.5%). The relationship between maternal BMI and neonatal birth weight showed that normal-weight mothers (BMI 18.5-24.9) had a higher percentage of babies with birth weights between 2.5-3.9 kg (82.02%), and only a small percentage had low birth weight (<2.5 kg, 16.85%). Interestingly, none of the mothers with a BMI >24.9 had neonates weighing less than 2.5 kg, while 87.50% had babies with birth weights in the 2.5-3.9 kg range, and 12.50% had neonates weighing ≥4.0 kg that was statistically significant (p=0.002) (Table 3). Similarly, in terms of head circumference, most babies born to mothers with higher BMI (>24.9) had a head circumference larger than 34 cm (75%) with a p-value of 0.001 (Table 4). In Table 5, the study investigated the impact of maternal hemoglobin levels on neonatal birth weight. Mothers with hemoglobin levels ≥10 gm/dl had a significantly higher percentage of babies (p=0.002) with normal birth weight (88.49%). In contrast, those with lower hemoglobin levels (<10 g/dl) had a greater proportion of low-birth-weight babies (59.02%). In Table 6, women with no prior births (nulliparous) and those with 1-3 births had a similar distribution, with most babies having birth weights in the 2.5-3.9 kg range. In contrast, mothers with higher parity (4-6) had a greater likelihood of giving birth to larger babies (33.33%) weighing ≥4.0 kg, which was not statistically significant. Gestational age in Table 7 demonstrated mothers who delivered between 37-40 weeks had 76.03% of neonates weighing between 2.5-3.9 kg, while those who delivered post-term (>40 weeks) had an even higher percentage (92.59%) of babies in this weight range which was highly significant (p=0.005).

Table 1: Demographic and clinical characteristics of study participants.

Table 2: Socio-economic characteristics of study participants.

Table 3: Distribution of neonates by birth-weight and maternal BMI.

Table 4: Distribution of neonates by head circumference and maternal BMI.

Table 5: Distribution of neonates by birth-weight and maternal hemoglobin.

Table 6: Distribution of neonates by birth weight and parity.

Table 7: Distribution of neonates by birth weight and gestational age.

This hospital-based study aimed to examine the key determinants of birth weight and head circumference of neonatal outcomes within the context of Bangladesh. While a community-based study would be more suitable for accurately assessing the relationship between maternal nutritional status and neonatal birth weight at term, this study provides valuable insights from a hospital setting. Body Mass Index (BMI), typically used as an indicator for nonpregnant women, was measured on postpartum day one to minimize inaccuracies, given the mothers' pregnant state. Hemoglobin levels were considered a crucial indicator of maternal nutritional health [10,11]. Neonatal well-being is largely influenced by birth weight and other anthropometric measurements. Therefore, it is recommended that factors like birth weight, length, head circumference, and chest circumference be assessed to understand the impact of maternal nutritional status on neonatal outcomes [12]. In this study, several factors affecting neonatal outcomes were analyzed, including maternal age, education, occupation, nutritional status, and parity. The study found the mean maternal age to be 24.6±4.7 years and the mean BMI to be 22.04 ± 1.32 kg/m², consistent with findings by Arif et al. (1998) and Ceesay et al. (1997) [11,13]. However, a key difference from Arif et al. (1998) was the higher education level of mothers in this study, most of whom had completed secondary education. In contrast, Arif et al. reported a majority of illiterate mothers [11]. The study revealed a significant relationship between maternal education and neonatal birth weight, with the highest percentage of low birth weight (LBW) infants born to illiterate mothers and fewer LBW infants among mothers with primary or secondary education. This finding suggests that maternal education is associated with better neonatal outcomes, a conclusion supported by other studies [14,15]. Additionally, the study found a higher proportion of LBW infants among mothers engaged in manual labor, particularly domestic workers, echoing findings by Hoa et al. (1996), who reported similar results among farming women in Vietnam [16]. Socioeconomic status was also a critical determinant of pregnancy outcomes. The majority of mothers in this study came from middle-class or affluent backgrounds, contributing to a lower incidence of LBW compared to other studies. Neonates from lower socioeconomic groups had a higher incidence of LBW, whereas those from wealthier families had fewer LBW infants, consistent with findings by Nazneen (2001) and Begum (1993) [14,17]. This study found a slightly higher mean birth weight than previous studies. For instance, Nazneen (2001) reported a mean birth weight of 2.5 ± 0.4 kg in her study conducted in Dhaka city hospitals [14]. However, the mean neonatal head circumference in this study was consistent with other research [8,18]. The difference in birth weight could be attributed to the better economic status of the current study's sample population. Economically stable mothers tend to be more health-conscious and proactive about antenatal care and immunization, leading to healthier birth weights [19]. In this study, the highest percentage of LBW infants was observed among teenage mothers. As maternal age increased, so did the birth weight of their infants, aligning with findings from other studies in Bangladesh [14]. The mean hemoglobin level in mothers was 10.4 ± 1.1 gm/dL, with the majority of LBW neonates born to mothers with hemoglobin levels below 10 gm/dL. In contrast, neonates with average or large-for-gestational-age weights were born to mothers with hemoglobin levels of 10 gm/dL or higher. Other studies have similarly shown that anemic mothers have a higher likelihood of giving birth to LBW infants [11]. Finally, the study indicated that neonatal birth weight increased with parity, a finding consistent with Kramer's (1987) analysis, which showed that both nulliparity and very high parity were associated with LBW [20]. Birth weight also tended to increase with gestational age [19], a trend observed in previous studies, including one by Akhter (1997), who found a linear relationship between birth weight and gestational period [18]. Although this study focused only on term pregnancies, it still identified differences in birth weight based on gestational age, with increased birth weight corresponding to longer gestational periods.

Limitations of the study: This study has several limitations. It was hospital-based and conducted in a single institution, which may limit the generalizability of the findings to the broader population, especially in rural areas. The study did not account for potential confounding variables such as maternal dietary intake, physical activity, or other environmental factors that could influence neonatal birth weight. The relatively short duration of data collection might have limited the sample size, and a longer study period could yield more comprehensive insights.

This study highlights the critical influence of maternal nutritional status, on the birth weight of term infants in Bangladesh. The findings reveal that mothers with normal BMI and adequate hemoglobin levels are significantly associated with higher birth weights, while factors such as low education levels and socioeconomic status also play vital roles in determining neonatal outcomes. The results emphasize the need for targeted interventions to improve maternal nutrition and education, particularly among low-income and illiterate populations, to enhance neonatal health and reduce the prevalence of low-birth-weight infants. By addressing these maternal risk factors, it may be possible to improve birth weight distributions and overall infant health in the region.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: The study was approved by the Institutional Ethics Committee

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