Researchers in Brazil followed pregnant women and new mothers to see how their eating habits changed from pregnancy through 8.5 months after birth. They found that women ate fewer carbohydrates and fiber over time, but ate more fat. Many women didn’t get enough vitamin D, vitamin B6, and iron during pregnancy. The study shows that pregnant women and new mothers need better nutrition advice to stay healthy and help their babies grow properly. Education about healthy eating during pregnancy and after birth is really important.

The Quick Take

  • What they studied: How the foods pregnant women eat change from the last three months of pregnancy through 8.5 months after having a baby, and whether they’re getting enough important nutrients.
  • Who participated: 369 pregnant women in Rio de Janeiro, Brazil who were followed from their third trimester of pregnancy. Some women completed follow-up visits at 1-3.5 months after birth (196 women), 3.5-6 months after birth (145 women), and 6-8.5 months after birth (108 women).
  • Key finding: Women’s eating patterns changed significantly over time. They ate less carbohydrates and fiber, but more fat. Many women didn’t eat enough vitamin D, vitamin B6, and iron—especially during pregnancy. About 30% of pregnant women got enough vitamin D, while 53% got enough vitamin B6, and 60% got enough iron.
  • What it means for you: If you’re pregnant or planning to be, you should pay special attention to getting enough vitamin D, iron, and B vitamins. Talk to your doctor about whether you need supplements. This is important for both your health and your baby’s development. After birth, keep paying attention to nutrition, especially if you’re breastfeeding.

The Research Details

This was a longitudinal study, which means researchers followed the same women over time and collected information about what they ate at different points. Women were recruited at a hospital in Rio de Janeiro during their third trimester of pregnancy (the last three months). Researchers asked women to remember everything they ate in a single 24-hour period using a detailed food recall method. This happened once during pregnancy and three more times after the baby was born. The researchers used a special Brazilian database to figure out exactly how many calories and nutrients were in the foods women reported eating. They used advanced statistical methods to figure out what women’s typical eating patterns were, since people’s eating can vary day to day.

Understanding how pregnant women’s nutrition changes over time is crucial because pregnancy and breastfeeding put extra demands on a mother’s body. If women don’t get enough nutrients, it can affect their own health and their baby’s development. By tracking real eating patterns, researchers can identify exactly which nutrients are missing and create better education programs to help women eat better.

This study has several strengths: it followed real women over time in a real-world setting, it used detailed food records rather than just asking general questions, and it included multiple follow-up visits. However, some women dropped out over time (fewer women completed later visits), which is common in long-term studies. The study was done in Brazil, so results may be slightly different in other countries with different food availability and eating habits.

What the Results Show

The study found clear patterns in how women’s eating changed from pregnancy to 8.5 months after birth. Carbohydrate intake decreased by about 1.84 grams per month, and fiber intake decreased by 0.41 grams per month. At the same time, total fat intake increased by 0.89 grams per month. This suggests that as women moved from pregnancy into the postpartum period, their diets shifted toward more fatty foods and away from whole grains and vegetables.

Vitamin and mineral intake also changed over time. Several important nutrients decreased: vitamin B2, vitamin B9 (folate), vitamin C, calcium, phosphorus, and magnesium all went down. However, some nutrients increased: vitamin E, selenium, and sodium intake went up over the study period.

When researchers looked at whether women were getting enough nutrients, they found serious gaps. During pregnancy, only about 30% of women got enough vitamin D, 53% got enough vitamin B6, and 60% got enough iron. These are all critical nutrients for pregnancy. By 8.5 months after birth, vitamin A and vitamin C intake adequacy had gotten even worse compared to pregnancy.

The study also found that certain factors predicted which women would have bigger changes in their nutrition. Women’s weight before pregnancy, their age, how much education they had, and their income level all affected how their eating patterns changed over time. This suggests that nutrition education programs need to be tailored to different groups of women, not one-size-fits-all.

This study adds important information to what we already know about pregnancy nutrition. Previous research has shown that pregnant women often don’t get enough iron and vitamin D, and this study confirms that pattern in a Brazilian population. The finding that nutrition actually gets worse in some ways after birth is particularly important, because many people think nutrition only matters during pregnancy. This research suggests that the postpartum period and breastfeeding period need just as much nutritional attention.

The main limitation is that fewer women completed all the follow-up visits. While 369 women started the study, only 108 completed the final visit at 8.5 months. This means the later results are based on a smaller group. The study was done in one hospital in Rio de Janeiro, so results might be different in other parts of Brazil or other countries. The study relied on women remembering what they ate, which can be inaccurate. Finally, the study only measured what women ate—it didn’t measure whether they actually absorbed and used all those nutrients, which can be affected by other health factors.

The Bottom Line

If you’re pregnant or planning to become pregnant, talk to your doctor about taking a prenatal vitamin that includes iron, vitamin D, and B vitamins. Eat plenty of whole grains, colorful vegetables, and fruits to get fiber and vitamins naturally. Include good sources of calcium like dairy products or fortified plant-based alternatives. If you’re breastfeeding, continue taking prenatal vitamins or a postnatal vitamin. These recommendations have moderate confidence because they’re based on one study in Brazil, but they align with general pregnancy nutrition guidelines.

Pregnant women and women planning pregnancy should definitely pay attention to these findings. New mothers who are breastfeeding should also focus on nutrition. Healthcare providers who work with pregnant women should use this information to improve nutrition counseling. Women with lower income or education levels may need extra support and resources to improve their nutrition. This study is less directly relevant to men or non-pregnant women, though the general principles about eating whole foods apply to everyone.

You won’t feel immediate changes from improving your nutrition, but over weeks and months, better nutrition can improve your energy levels, mood, and overall health. For your baby, good nutrition during pregnancy affects development throughout pregnancy and early childhood. If you’re breastfeeding, improved nutrition can improve milk quality within days to weeks. Most people notice sustained energy improvements within 2-4 weeks of better eating habits.

Want to Apply This Research?

  • Track your intake of key nutrients: vitamin D (aim for 600 IU daily during pregnancy), iron (27 mg daily), vitamin B6 (1.9 mg daily), and calcium (1000 mg daily). Use the app to log foods and see if you’re hitting these targets. Take a photo of your prenatal vitamin bottle to remind yourself to take it daily.
  • Set a daily reminder to take your prenatal vitamin. Add one new whole grain, one new vegetable, and one new calcium source to your weekly meal plan. Replace one sugary drink per day with water or milk. Plan one meal per week that includes iron-rich foods like beans, lean meat, or fortified cereals.
  • Weekly check-in: Review your nutrient tracking to see which nutrients you’re consistently missing. Monthly assessment: Take progress photos of your meals to see if you’re eating more colorful, whole foods. Quarterly: Share your nutrition data with your healthcare provider to discuss whether supplements are needed. Set alerts for prenatal vitamin refills so you never run out.

This research describes what happened in one study of Brazilian women and should not replace personalized medical advice. Every pregnancy is different, and nutritional needs vary based on individual health conditions, medications, and other factors. Always consult with your obstetrician, midwife, or registered dietitian before making significant changes to your diet or starting supplements during pregnancy or while breastfeeding. This information is for educational purposes and is not a substitute for professional medical diagnosis, treatment, or advice. If you have concerns about your nutrition during pregnancy or postpartum, contact your healthcare provider immediately.