Researchers studied 152 mothers and newborns in Croatia to understand how what mothers eat and their weight during pregnancy affects important minerals in babies’ first poop (called meconium). They found that mothers who eat more fruits and vegetables, along with their weight before and during pregnancy, influence the levels of iron, zinc, copper, and manganese in their babies. Interestingly, mothers with higher weight before pregnancy had babies that were slightly larger at birth. This research suggests that eating a balanced diet and maintaining a healthy weight during pregnancy may help babies develop properly.

The Quick Take

  • What they studied: How a mother’s diet, weight, and lifestyle during pregnancy affect the amount of important minerals (iron, zinc, copper, and manganese) that babies are exposed to before birth, and whether these minerals connect to how big babies are at birth.
  • Who participated: 152 pairs of mothers and newborns from different areas in Croatia. Researchers collected the babies’ first poop within 24 hours of birth and asked mothers questions about what they ate, their weight, and their lifestyle habits during pregnancy.
  • Key finding: A mother’s weight before pregnancy and what she eats significantly influence the levels of essential minerals in her baby’s body. Mothers who ate more meat and had higher weight before pregnancy had babies that were slightly longer and heavier at birth.
  • What it means for you: If you’re pregnant or planning to become pregnant, eating a balanced diet with fruits, vegetables, and appropriate protein, along with maintaining a healthy weight, may help your baby develop optimally. However, this is one study and more research is needed before making major changes to your diet.

The Research Details

This was a cross-sectional study, which means researchers collected information from mothers and babies at one point in time (around birth) rather than following them over months or years. Researchers recruited 152 mother-infant pairs from various regions in Croatia and collected the babies’ first poop (meconium) within 24 hours after birth. They then measured how much iron, zinc, copper, and manganese were in each sample.

At the same time, researchers asked mothers detailed questions about what they ate during pregnancy, whether they took supplements, if they smoked, and other lifestyle factors. They also recorded information from hospital records about the mothers’ weight before pregnancy and at delivery, as well as measurements of the babies at birth.

The researchers then used statistical methods to look for patterns—for example, did mothers who ate more vegetables have different mineral levels in their babies compared to mothers who ate less vegetables? They also checked whether these mineral levels were connected to how big or long the babies were at birth.

This research approach is useful because it captures real-world information about what pregnant women actually eat and how their bodies change during pregnancy, then connects this to what’s happening in their babies’ bodies. By looking at meconium (the baby’s first poop), researchers can measure what minerals the baby was exposed to during pregnancy without needing to do invasive tests. This type of study is good for finding patterns and connections, though it can’t prove that one thing directly causes another.

This study has some strengths: it measured actual mineral levels in meconium rather than just asking about them, and it collected detailed information about mothers’ diets and lifestyles. However, the study only included 152 families from one region of Croatia, so the results might not apply to all populations. The study design (cross-sectional) is good for finding connections but can’t prove cause-and-effect relationships. The researchers used appropriate statistical methods for their data type, which is a positive sign.

What the Results Show

The study found that the amounts of iron, zinc, copper, and manganese in babies’ meconium varied quite a bit from baby to baby. Interestingly, iron and copper levels were strongly connected—babies with higher iron also tended to have higher copper.

A mother’s weight before pregnancy was important: mothers who weighed more before getting pregnant had babies with lower iron levels in their meconium, but higher zinc levels. A mother’s weight at delivery was also linked to zinc levels.

What mothers ate made a difference too. Mothers who ate more fruit had babies with higher copper levels. Surprisingly, mothers who ate more vegetables had babies with lower iron levels. Mothers who drank a moderate amount of tea (not too much, not too little) had babies with higher zinc levels.

Finally, mothers who ate more meat and those who weighed more before pregnancy had babies that were slightly longer and heavier at birth. This suggests that maternal nutrition and weight status during pregnancy may influence how babies grow.

The study found no significant connections between meconium mineral levels and whether mothers smoked, where they lived, or whether they took supplements. This was somewhat surprising, as researchers expected these factors might matter more. The lack of connection with supplement use suggests that the minerals babies are exposed to come mainly from the food mothers eat rather than from pills.

Previous research has shown that maternal nutrition affects fetal development, and this study adds to that knowledge by showing specific connections between diet, maternal weight, and mineral levels in newborns. The finding that maternal BMI influences mineral exposure is relatively new and suggests that maintaining a healthy weight during pregnancy may be just as important as eating the right foods. The lack of connection with smoking was unexpected, as some earlier studies suggested smoking might affect mineral levels, so this area needs more research.

This study only included 152 families from one region of Croatia, so the results might not apply to all populations around the world. The study design can show that two things are connected (like eating more fruit and higher copper) but cannot prove that one causes the other. Researchers relied on mothers to remember and accurately report what they ate during pregnancy, which can be imperfect. The study didn’t measure all possible factors that might influence mineral levels, and it only looked at one point in time rather than following families over time.

The Bottom Line

Based on this research, pregnant women should aim to eat a balanced diet with adequate fruits, vegetables, and protein sources like meat. Maintaining a healthy weight before and during pregnancy appears important for fetal development. However, these recommendations have moderate confidence because this is one study in one region. Pregnant women should follow their doctor’s specific guidance about nutrition and weight gain, as individual needs vary.

This research is most relevant to pregnant women and those planning pregnancy who want to optimize their nutrition. It’s also important for healthcare providers advising pregnant patients. The findings may be most applicable to populations similar to those in the study (European populations), though the basic principles about balanced nutrition likely apply more broadly. This research is less relevant to people who are not pregnant, though it highlights the importance of good nutrition for all women of childbearing age.

The effects of maternal nutrition on fetal development happen throughout pregnancy, so the benefits of eating well and maintaining a healthy weight would accumulate over the nine months of pregnancy. You wouldn’t see changes in days or weeks, but rather the effects would be measurable at birth through baby’s size and development. Long-term effects on the baby’s health may take months or years to become apparent.

Want to Apply This Research?

  • Track daily fruit and vegetable servings during pregnancy (aim for 5+ servings per day) and monitor pre-pregnancy weight and weight gain during pregnancy to ensure it falls within recommended ranges (typically 25-35 pounds for normal weight women). Record weekly weights and compare to expected gain patterns.
  • Use the app to log meals and receive feedback on fruit and vegetable intake. Set a goal to include at least one fruit and one vegetable at each meal. Track protein sources including lean meats, fish, eggs, and legumes. Monitor weight gain progress against trimester-specific targets provided by your healthcare provider.
  • Create a pregnancy nutrition dashboard that shows weekly fruit/vegetable servings, protein intake, and weight gain trajectory. Compare your actual intake against recommended daily amounts. Set reminders for meal planning and grocery shopping to ensure balanced nutrition throughout pregnancy. Share reports with your healthcare provider at prenatal visits.

This research describes associations between maternal diet, weight, and newborn outcomes but does not prove cause-and-effect relationships. Individual pregnancy needs vary significantly based on health status, pre-existing conditions, and other factors. Pregnant women should not make major changes to their diet or supplement routine based on this study alone. Always consult with your obstetrician, midwife, or registered dietitian before making decisions about nutrition during pregnancy. This information is for educational purposes and should not replace personalized medical advice from your healthcare provider.