Gram Research analysis of 993 pregnancies found that mothers with inadequate folic acid intake had babies that developed about one day slower and were 1.24 millimeters smaller (3.7% reduction) at 10 weeks of gestation. Mothers with low blood folate levels below 25.5 nmol/l showed the most significant delays in embryonic development. Starting folic acid supplements before conception appears important for supporting optimal early baby development.
A Gram Research analysis of nearly 1,000 pregnancies found that mothers who took folic acid supplements before conception had babies with better early development. Researchers used advanced 3D ultrasound to measure embryo growth at 7 and 9 weeks of pregnancy. Babies whose mothers had low folate levels were slightly smaller and developed about one day slower than babies whose mothers had adequate folate. Surprisingly, smoking, alcohol, caffeine, and exercise didn’t show significant effects on early embryo development in this study. The findings support the long-standing recommendation that women planning pregnancy should start taking folic acid early.
Key Statistics
A 2026 cohort study of 993 pregnancies in the Netherlands found that inadequate folic acid supplementation was associated with a 0.51-day delay in embryonic development and a 0.72-millimeter reduction in crown-rump length at 10 weeks of gestation.
According to research reviewed by Gram, mothers with insufficient serum folate levels below 25.5 nmol/l showed a 1.01-day developmental delay and a 1.24-millimeter reduction in embryo size, representing a 3.7% growth reduction at 10 weeks of pregnancy.
A 2026 population-based cohort study of 993 pregnancies found no significant associations between smoking, alcohol consumption, caffeine intake, or physical activity and embryonic morphologic development in the first 10 weeks of pregnancy.
Research from the Generation R Next Study showed that periconception folic acid supplementation was the only modifiable lifestyle factor significantly associated with embryonic development and growth when measured using advanced 3D ultrasound at 7 and 9 weeks of gestation.
The Quick Take
- What they studied: Whether a mother’s lifestyle choices before and early in pregnancy affect how well her baby develops in the first few weeks, especially looking at folic acid intake, smoking, alcohol, caffeine, and exercise.
- Who participated: 993 women from Rotterdam, Netherlands who were pregnant between 2017 and 2021. All pregnancies were naturally conceived, single babies, and had clear dating information and detailed ultrasound scans in the first 10 weeks.
- Key finding: Mothers who didn’t take enough folic acid had babies that were about 1.24 millimeters smaller (3.7% reduction) and developed about one day slower. Mothers with very low blood folate levels (below 25.5 nmol/l) showed the biggest delays.
- What it means for you: If you’re planning to get pregnant, starting folic acid supplements before conception appears important for your baby’s early development. The effect is small but measurable. This study doesn’t prove folic acid is the only factor, but it supports existing medical recommendations.
The Research Details
Researchers followed nearly 1,000 pregnant women from the Generation R Next Study in the Netherlands. Before pregnancy and early in pregnancy, women answered detailed questions about their lifestyle habits like smoking, drinking alcohol, caffeine use, exercise, and whether they took folic acid supplements. Doctors measured the women’s folate levels in their blood. Then, using advanced 3D ultrasound technology, researchers carefully measured each baby’s development at 7 weeks and 9 weeks of pregnancy. They looked at specific features like how the baby’s limbs were positioned, the curve of the body, and brain development. They also measured the baby’s length from crown to rump (the top of the head to the bottom of the buttocks). The researchers used statistical methods to see which lifestyle factors were connected to differences in development, while accounting for other factors like the mother’s age, education, and ethnicity.
This study design is strong because it followed women from before pregnancy through early pregnancy, capturing lifestyle information at the right time. Using 3D ultrasound with virtual reality techniques provides very detailed measurements of early development that older studies couldn’t measure. By looking at many lifestyle factors at once and adjusting for confounding factors, the researchers could isolate which factors truly mattered. This approach is more reliable than studies that only look at one factor or rely on memory from later in pregnancy.
The study included nearly 1,000 pregnancies with complete data, which is a solid sample size. The researchers used strict criteria to ensure accurate pregnancy dating, reducing errors. However, women reported their own lifestyle habits, which can be unreliable due to memory problems or not wanting to admit unhealthy behaviors. The study population was relatively healthy overall, so results might not apply to women with serious health problems. The researchers carefully adjusted their analysis for many other factors that could influence results, strengthening confidence in the findings.
What the Results Show
The most important finding was about folic acid. Mothers who didn’t take enough folic acid supplements had babies that developed about half a day slower (0.51 days) and were about 0.72 millimeters shorter at 10 weeks of pregnancy. When researchers looked at blood folate levels specifically, mothers with very low folate (below 25.5 nmol/l) had even bigger delays: their babies developed about one full day slower and were 1.24 millimeters shorter, which equals a 3.7% reduction in size. To put this in perspective, a typical baby at 10 weeks is about 33 millimeters long, so 1.24 millimeters is a noticeable but small difference. These associations remained strong even after accounting for other factors like maternal age, education, and ethnicity.
Surprisingly, smoking, alcohol consumption, caffeine intake, and physical activity showed no significant associations with embryonic development or growth in this study. This doesn’t mean these factors are safe during pregnancy, but it suggests they may not affect development in the very earliest weeks measured here. The lack of findings for smoking and alcohol was unexpected based on previous research, possibly because the study population was relatively healthy with low rates of heavy smoking or drinking.
Previous studies have suggested that smoking and folic acid use affect first trimester growth, but this is one of the first large studies to carefully examine how these factors affect the earliest stages of embryonic development using detailed 3D imaging. The folic acid findings align with decades of research showing folate is critical for early development. The unexpected null findings for smoking and alcohol may reflect that this Dutch population had generally healthy lifestyle patterns, or that effects on very early development are smaller than effects later in pregnancy.
Women reported their own lifestyle habits from memory, which can be inaccurate. Pregnancy dating was based on the last menstrual period, which can be off by several days due to natural variation in cycle length. The study population was relatively healthy and well-educated, so results may not apply to women with higher-risk lifestyles or health conditions. The study only measured development up to 10 weeks, so we don’t know if these early differences persist throughout pregnancy or affect birth outcomes.
The Bottom Line
Women planning pregnancy should start taking folic acid supplements at least one month before trying to conceive to ensure adequate blood folate levels. The standard recommendation is 400 micrograms daily, though some women need higher doses based on medical history. This evidence supports existing public health guidelines with moderate to strong confidence. Women who are already pregnant should start folic acid immediately if they haven’t already.
Any woman planning to become pregnant should pay attention to these findings. Women with a history of neural tube defects, diabetes, or certain medications should discuss folic acid dosing with their doctor. The findings are most relevant to women in developed countries with access to supplements. Women who are already pregnant should focus on starting folic acid now rather than worrying about the past.
Folic acid needs to build up in your system before pregnancy, which is why starting before conception matters. The critical window is from about 28 days before conception through the first 28 days of pregnancy, when the baby’s neural tube is forming. You should expect to take folic acid for at least several months if you’re planning pregnancy.
Frequently Asked Questions
Does folic acid before pregnancy really affect how my baby develops?
Research shows mothers with adequate folic acid had babies that developed slightly faster and were measurably larger in early pregnancy. The effect is small but consistent. Starting folic acid before conception helps ensure your body has enough folate when your baby’s development begins.
How much folic acid should I take if I’m planning to get pregnant?
The standard recommendation is 400 micrograms daily starting at least one month before trying to conceive. Some women need higher doses based on medical history, medications, or previous pregnancies. Ask your doctor about the right dose for your situation.
Can smoking or drinking alcohol in early pregnancy harm my baby’s development?
This study didn’t find measurable effects on very early embryo development, but that doesn’t mean these substances are safe. Other research shows smoking and alcohol can harm pregnancy at later stages. It’s best to avoid both when planning pregnancy and throughout pregnancy.
Is it too late to start folic acid if I’m already pregnant?
Start folic acid immediately if you haven’t already. While the preconception period is ideal, taking folic acid early in pregnancy still provides important benefits for your baby’s development. Don’t delay starting because you didn’t begin before pregnancy.
What if I have low folate levels? How do I fix that?
Taking a daily folic acid supplement will raise your blood folate levels within weeks. Eating folate-rich foods like leafy greens, beans, and fortified grains also helps. Ask your doctor to recheck your blood folate levels after starting supplements to confirm they’re adequate.
Want to Apply This Research?
- Log daily folic acid supplement intake and track blood folate levels if tested by your doctor. Set a reminder to take your supplement at the same time each day, and record the date you started supplementation relative to when you’re trying to conceive.
- If planning pregnancy, add a daily folic acid supplement to your morning routine immediately. Use the app to set a daily reminder and track consistency. If you’re already pregnant and haven’t started folic acid, begin today and log it in the app.
- Track supplement adherence daily for at least three months before conception. If possible, ask your doctor to check blood folate levels and log the results in the app. Continue tracking throughout the first trimester to maintain consistency.
This article summarizes research findings and should not replace medical advice from your doctor. Folic acid supplementation recommendations may vary based on individual health factors, medications, and medical history. Women planning pregnancy or currently pregnant should consult with their healthcare provider about appropriate folic acid dosing and any concerns about early pregnancy development. This research describes associations observed in one population and may not apply to all individuals or groups. Always follow your doctor’s personalized recommendations for prenatal care.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.