Research shows that low birth weight babies are significantly more likely when mothers have less education, lower income, anemia, chronic illnesses, poor nutrition, or premature labor. According to Gram Research analysis of a 2025 case-control study of 171 mothers in Nepal, mothers with these risk factors were 3 to 8 times more likely to deliver babies weighing less than 5.5 pounds. The good news: most of these risks are preventable through prenatal care, nutrition support, and illness management.
Researchers in Nepal studied 171 mothers to understand why some babies are born weighing less than 5.5 pounds—a condition called low birth weight that can affect a baby’s health. According to Gram Research analysis, the study found that mothers with less education, lower income, anemia (low iron in blood), poor nutrition, and untreated illnesses during pregnancy were significantly more likely to have smaller babies. The good news? Many of these risks can be prevented with better prenatal care, nutrition, and education. This research shows that supporting pregnant mothers’ health and education could help more babies be born at healthy weights.
Key Statistics
A 2025 case-control study of 171 mothers in Nepal found that premature birth was the strongest risk factor for low birth weight babies, increasing risk 8-fold compared to full-term pregnancies.
According to research reviewed by Gram, mothers with chronic illnesses like diabetes or high blood pressure were 8 times more likely to deliver low birth weight babies in a 2025 Nepal study of 171 mothers.
A 2025 case-control study of 171 mothers found that maternal anemia (low hemoglobin) increased the risk of low birth weight babies by 6 times, making it one of the most modifiable risk factors.
Research from a 2025 Nepal study of 171 mothers showed that mothers with less formal education were 6 times more likely to have low birth weight babies, highlighting education’s role in maternal health outcomes.
The Quick Take
- What they studied: What factors make babies more likely to be born weighing less than 2,500 grams (about 5.5 pounds), which doctors call low birth weight
- Who participated: 171 mothers who gave birth at a hospital in Kathmandu, Nepal between August 2024 and January 2025. The group included 57 mothers whose babies weighed less than 5.5 pounds and 114 mothers whose babies weighed 5.5 pounds or more
- Key finding: Nine major risk factors were identified, with the strongest being premature birth (babies born too early), chronic illnesses, low hemoglobin levels, and mothers having less education. Mothers with these risk factors were 3 to 8 times more likely to have smaller babies
- What it means for you: If you’re pregnant or planning pregnancy, getting regular prenatal checkups, treating anemia, eating nutritious food, managing any chronic health conditions, and completing your education can significantly reduce the chance of having a low birth weight baby. This is especially important in low-income settings
The Research Details
Researchers used a case-control study design, which is like comparing two groups to find differences. They looked at 57 mothers whose babies were born small (cases) and compared them to 114 mothers whose babies were born at normal weight (controls). The mothers were matched by age to make the comparison fair. Researchers collected information through interviews and by reviewing medical records from August 2024 to January 2025.
They asked mothers about their education level, family income, diet, medical history, and pregnancy experiences. They also checked medical records for information about hemoglobin levels, weight before pregnancy, how many children the mother had before, how long the pregnancy lasted, and any illnesses during pregnancy. This combination of interview and medical record data gave researchers a complete picture of each mother’s situation.
Case-control studies are particularly useful for studying rare outcomes like low birth weight because researchers can focus on mothers who experienced the problem and compare them directly to those who didn’t. This design is efficient and can identify multiple risk factors at once. By studying mothers in a real hospital setting in Nepal, the findings reflect actual conditions in low-resource countries where low birth weight is most common and most dangerous
The study was published in PLOS ONE, a respected peer-reviewed journal. The researchers used proper statistical methods (logistic regression) to identify which factors were truly important versus which might have been coincidental. The study was conducted in a real hospital setting, making results relevant to actual practice. However, the study only included mothers from one hospital in one city, so results may not apply everywhere. The relatively small sample size (171 mothers) means some findings should be confirmed with larger studies
What the Results Show
The research identified nine independent risk factors for low birth weight babies. The strongest risk factor was premature birth—babies born before 37 weeks of pregnancy were 8 times more likely to be small. Mothers with chronic illnesses like diabetes or high blood pressure were also 8 times more likely to have small babies. Low hemoglobin levels (anemia) increased risk 6 times, and mothers who weighed less before pregnancy had 5 times higher risk.
Maternal education was surprisingly important: mothers with less education were 6 times more likely to have small babies, possibly because education helps mothers understand nutrition and prenatal care. Family income mattered too—mothers with lower per capita income were nearly 3 times more likely to have small babies. The number of previous pregnancies also affected risk: mothers having their first or second baby were 5 times more likely to have a small baby compared to mothers with more experience.
Two other significant factors were poor diet and illness during pregnancy. Mothers with inadequate nutrition were nearly 5 times more likely to have small babies, and mothers who got sick during pregnancy were 3 times more likely to deliver small babies. These findings suggest that low birth weight isn’t caused by one thing but by multiple interconnected problems—poverty, lack of education, poor nutrition, and untreated health conditions all working together.
The study found that the combination of multiple risk factors was particularly dangerous. Mothers who had several of these problems together—for example, low income, less education, anemia, and poor nutrition—faced much higher risk than mothers with just one problem. This suggests that interventions should address multiple factors simultaneously rather than focusing on just one issue. The research also highlighted that many of these risk factors are preventable or treatable with proper healthcare access
This study confirms what previous research has shown: low birth weight in low-resource countries is caused by a combination of socioeconomic factors (poverty, education), maternal health factors (anemia, chronic illness), and pregnancy factors (premature birth, poor nutrition). The specific risk factors and their strength align with findings from other studies in South Asia and Africa. However, this is one of the first studies to comprehensively examine all these factors together in Nepal, filling a gap in regional research
The study only included mothers from one hospital in Kathmandu, so results may not apply to rural areas or other countries. The sample size of 171 mothers is relatively small, which means some findings might change if a larger study were done. The study only looked at mothers who delivered at this particular hospital, potentially missing mothers who delivered at home or other facilities. Because the study was conducted over just 6 months, seasonal factors weren’t examined. Finally, the study couldn’t prove that these factors directly caused low birth weight—only that they were associated with it
The Bottom Line
Strong evidence supports: (1) Regular prenatal care to detect and treat anemia and other health problems; (2) Nutritional counseling and support, especially for low-income mothers; (3) Education programs for women about pregnancy health; (4) Management of chronic illnesses before and during pregnancy; (5) Screening for premature labor risk. Moderate evidence supports: (6) Family income support programs; (7) Dietary supplementation for malnourished mothers. These recommendations are most applicable in low-resource settings like Nepal but have relevance globally
Pregnant women and those planning pregnancy should pay special attention if they have any of these risk factors: less formal education, low family income, anemia, chronic illnesses, poor nutrition, or previous small babies. Healthcare providers in low-resource settings should use these findings to identify high-risk mothers early. Public health officials should consider these factors when designing maternal health programs. The findings are most relevant to South Asian countries with similar healthcare systems but have broader implications for maternal health globally
Benefits from addressing these risk factors depend on when interventions start. Treating anemia takes 2-3 months to improve hemoglobin levels. Nutritional improvements can be seen within weeks but take months to significantly affect baby weight. Prenatal care benefits accumulate throughout pregnancy, with the most critical period being the last trimester. Starting interventions early in pregnancy—ideally before pregnancy—produces the best outcomes
Frequently Asked Questions
What are the main causes of babies being born too small?
A 2025 Nepal study of 171 mothers identified nine main causes: premature birth, chronic illnesses, anemia, low pre-pregnancy weight, less maternal education, low family income, high parity, poor diet, and illness during pregnancy. These factors often occur together, multiplying risk.
Can low birth weight be prevented?
Yes, according to 2025 research, most risk factors are preventable or treatable. Regular prenatal care, treating anemia, good nutrition, managing chronic illnesses, and education can significantly reduce low birth weight risk. Starting interventions early in pregnancy produces the best outcomes.
How much does anemia increase the risk of small babies?
A 2025 case-control study found that mothers with low hemoglobin levels were 6 times more likely to deliver low birth weight babies. Anemia is particularly important because it’s treatable with iron supplementation and dietary changes.
Does a mother’s education really affect baby birth weight?
Yes, a 2025 Nepal study of 171 mothers found that mothers with less education were 6 times more likely to have low birth weight babies. Education likely helps mothers understand nutrition, recognize pregnancy complications, and access prenatal care.
What should pregnant women do to prevent low birth weight?
Get regular prenatal checkups, treat anemia and chronic illnesses, eat nutritious foods rich in protein and iron, maintain healthy weight gain, avoid illness when possible, and seek immediate care if complications develop. Starting these practices before pregnancy is ideal.
Want to Apply This Research?
- Track hemoglobin levels at each prenatal visit, dietary intake (servings of protein, iron-rich foods, fruits/vegetables daily), prenatal appointment attendance, and any illness episodes. Monitor weight gain trajectory against recommended guidelines for pre-pregnancy weight
- Users can log daily iron-rich food intake, set reminders for prenatal appointments, track symptoms of anemia (fatigue, shortness of breath), record any illnesses and their treatment, and monitor weight weekly. The app could provide nutrition education specific to low-income settings and alert users to concerning symptoms
- Create a risk factor dashboard showing which factors apply to the user, track progress on modifiable factors (nutrition, anemia treatment, appointment attendance), set goals for each trimester, and provide alerts if concerning patterns emerge. Long-term tracking should continue postpartum to monitor infant outcomes and inform future pregnancies
This article summarizes research findings and should not replace professional medical advice. If you are pregnant or planning pregnancy, consult with your healthcare provider about your individual risk factors and appropriate prenatal care. This study was conducted in Nepal and may not apply to all populations or healthcare settings. The findings identify associations, not definitive causes. Always discuss any concerns about pregnancy health with a qualified healthcare professional.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.