According to Gram Research analysis, newborns are born with significantly lower vitamin D levels than their mothers—about 13% less on average. A 2026 cross-sectional study of 92 mother-baby pairs in Nigeria found that while only 2% of mothers had severe vitamin D deficiency, 65% of newborns had insufficient vitamin D at birth. Importantly, a mother’s adequate vitamin D level does not guarantee her baby will have enough, suggesting newborns may need independent vitamin D supplementation.
A new study from Nigeria shows that newborns are born with lower vitamin D levels than their mothers, even when mothers have adequate amounts. Researchers tested 92 mother-baby pairs and found that babies had about 13% less vitamin D in their blood at birth compared to their mothers. Surprisingly, two-thirds of the newborns didn’t have enough vitamin D, while their mothers seemed fine. This finding suggests that doctors can’t assume a baby has enough vitamin D just because the mother does—babies may need their own vitamin D support right from birth.
Key Statistics
A 2026 cross-sectional study of 92 mother-baby pairs in Nigeria found that newborns had an average vitamin D level 3.7 units lower than their mothers (24.85 ng/mL versus 28.54 ng/mL), representing a 13% reduction at birth.
According to research reviewed by Gram, 65.2% of newborns in the study had insufficient vitamin D levels at birth, compared to only 52.2% of mothers, despite the mothers’ generally adequate status.
A 2026 Nigerian study of 92 maternal-neonatal pairs found that maternal vitamin D sufficiency was an unreliable predictor of neonatal vitamin D status, with significant discordance between mother and baby vitamin D categories (p = 0.003).
The 2026 cross-sectional analysis showed that the maternal-to-cord vitamin D ratio was 1.20, meaning babies consistently received only about 83% of their mothers’ vitamin D levels at birth.
The Quick Take
- What they studied: Whether newborns have the same amount of vitamin D as their mothers at birth, and how big the difference is
- Who participated: 92 healthy pregnant women and their newborn babies at a hospital in Ilorin, Nigeria (a location near the equator where there’s plenty of sunshine)
- Key finding: Newborns had about 3.7 units less vitamin D than their mothers at birth. Two-thirds of babies didn’t have enough vitamin D, even though most mothers had adequate levels.
- What it means for you: If you’re pregnant or planning to be, having enough vitamin D yourself may not be enough to protect your baby. Your newborn may need separate vitamin D support. Talk to your doctor about vitamin D supplementation during pregnancy and for your newborn.
The Research Details
Researchers in Nigeria collected blood samples from 92 pregnant women right when they gave birth and from their newborns’ umbilical cords. They measured the amount of vitamin D in each blood sample using a lab test. They then compared the mother’s vitamin D level to the baby’s level to see how much difference there was.
The researchers classified vitamin D levels into three categories: deficient (very low), insufficient (somewhat low), or sufficient (adequate). They looked at whether mothers and babies fell into the same category or different ones. They also checked if the time of birth (how early or late the baby was born) made a difference in vitamin D levels.
This type of study is called a cross-sectional study, which means researchers took a snapshot in time rather than following people over months or years. It’s useful for understanding what’s happening at one specific moment.
Understanding the vitamin D gap between mothers and babies is important because vitamin D is crucial for bone health, immune function, and overall development in newborns. If babies are born with insufficient vitamin D, they may need supplementation right away. This research helps doctors know they can’t rely on the mother’s vitamin D level alone to predict the baby’s needs.
This study has several strengths: it used a reliable lab test to measure vitamin D, it had paired samples from mothers and babies (making comparisons more accurate), and it was conducted in a real hospital setting. However, the study only included 92 pairs from one hospital in Nigeria, so results may not apply to all populations. The study was published in 2026 in a peer-reviewed journal focused on maternal and newborn health.
What the Results Show
Mothers had an average vitamin D level of 28.54 ng/mL, while their newborns had an average of 24.85 ng/mL. This means babies were born with about 3.7 units less vitamin D than their mothers—a difference that was statistically significant (meaning it’s unlikely to be due to chance).
When researchers looked at vitamin D categories, they found an interesting mismatch: only 2.2% of mothers had deficient vitamin D, but 52.2% had insufficient levels (not quite enough). For babies, the picture was worse: 65.2% had insufficient vitamin D. This means that even though most mothers weren’t severely deficient, most babies still didn’t have adequate vitamin D at birth.
The most striking finding was that a mother’s vitamin D status didn’t reliably predict her baby’s status. Some mothers with sufficient vitamin D had babies with insufficient levels, and vice versa. This discordance (disagreement) was statistically significant, suggesting that maternal vitamin D alone cannot be used to determine whether a baby will have adequate vitamin D.
Babies born very early (between 28 and 32 weeks of pregnancy) had slightly higher vitamin D levels than other babies, but their levels still fell below the ‘sufficient’ threshold of 30 ng/mL. However, these differences based on how early babies were born were not statistically significant, meaning they could be due to chance. The vitamin D levels of mothers and babies were positively correlated (r = 0.498), meaning when mothers had higher levels, babies tended to have higher levels too—but the relationship wasn’t strong enough to be predictive.
This research adds to existing knowledge that vitamin D doesn’t transfer perfectly from mother to baby across the placenta. The 13% reduction in vitamin D from mother to baby (the 1.20 ratio) is consistent with what researchers have observed in other parts of the world. However, this is one of the first studies to carefully measure this gap in sub-Saharan Africa, where vitamin D deficiency patterns may differ from other regions due to differences in sun exposure, diet, and genetics.
The study only included 92 mother-baby pairs from one hospital in Nigeria, so results may not apply to other regions or populations. The study was conducted at one point in time, so researchers couldn’t track whether vitamin D levels changed over time. The study didn’t measure other factors that might affect vitamin D levels, such as skin tone, diet, or sun exposure habits. Additionally, the study didn’t follow babies after birth to see if low vitamin D at birth caused any health problems.
The Bottom Line
Pregnant women should ensure they have adequate vitamin D levels (at least 30 ng/mL) through sunlight exposure, diet, or supplements—this is a strong recommendation based on this and other research. However, this study suggests that maternal vitamin D supplementation alone may not be sufficient to ensure babies are born with adequate vitamin D. Healthcare providers should consider recommending vitamin D supplementation for newborns, particularly in regions with limited sun exposure or where vitamin D insufficiency is common. This recommendation has moderate confidence because it’s based on one study in one location.
Pregnant women, new mothers, and healthcare providers should pay attention to these findings. This is especially important for people living in areas with limited sun exposure, those with darker skin tones (which reduces vitamin D production from sunlight), and those with dietary restrictions that limit vitamin D intake. Healthcare providers in sub-Saharan Africa and similar regions should consider this research when developing vitamin D supplementation policies for pregnant women and newborns.
Vitamin D status at birth reflects vitamin D accumulation during pregnancy. To see benefits from maternal supplementation, pregnant women would need to start supplementing several months before delivery. For newborns, vitamin D supplementation typically shows benefits within weeks to months in terms of preventing deficiency-related problems, though long-term bone health benefits develop over years.
Frequently Asked Questions
If I have enough vitamin D during pregnancy, will my baby be born with enough vitamin D?
Not necessarily. A 2026 study of 92 mother-baby pairs found that 65% of newborns had insufficient vitamin D despite most mothers having adequate levels. Maternal vitamin D alone doesn’t guarantee adequate baby vitamin D, so newborns may need independent supplementation.
How much lower is a newborn’s vitamin D compared to the mother’s?
Newborns are born with approximately 13% less vitamin D than their mothers. The study found an average difference of 3.7 ng/mL, with babies averaging 24.85 ng/mL compared to mothers’ 28.54 ng/mL.
What percentage of newborns don’t have enough vitamin D at birth?
According to the 2026 Nigerian study, 65.2% of newborns had insufficient vitamin D levels at birth (below 30 ng/mL), even though vitamin D deficiency was rare in both mothers and babies.
Should pregnant women take vitamin D supplements to protect their babies?
Yes, pregnant women should maintain adequate vitamin D levels (at least 30 ng/mL) through sunlight, diet, or supplements. However, this study suggests maternal supplementation alone may not be sufficient—newborns may also need their own vitamin D support starting at birth.
Does the time of birth affect how much vitamin D a baby has?
The study found that babies born very early (28-32 weeks) had slightly higher vitamin D levels than others, but the difference wasn’t statistically significant. All groups remained below the adequate threshold regardless of gestational age.
Want to Apply This Research?
- Track maternal vitamin D levels during pregnancy (measured in ng/mL) at each prenatal visit, and record newborn vitamin D screening results at birth and at the first pediatric visit. Note the difference between maternal and newborn levels to monitor the gradient.
- If you’re pregnant, use the app to set reminders for daily vitamin D supplementation (typically 1,000-2,000 IU for pregnant women, but follow your doctor’s recommendation). After birth, set reminders to give your newborn their prescribed vitamin D drops, typically 400 IU daily.
- Log vitamin D supplementation compliance during pregnancy and track newborn vitamin D supplementation for the first year of life. Record any vitamin D blood test results when available. Monitor for signs of vitamin D deficiency in babies (such as delayed bone development) and report concerns to your pediatrician.
This research summary is for educational purposes only and should not replace professional medical advice. Vitamin D supplementation during pregnancy and for newborns should be discussed with your healthcare provider, as recommendations may vary based on individual factors such as skin tone, geographic location, dietary intake, and medical history. Always follow your doctor’s specific recommendations for vitamin D supplementation during pregnancy and for your newborn. If you have concerns about your vitamin D levels or your baby’s vitamin D status, consult with your obstetrician or pediatrician.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.