List of studies about vitamin D and pregnancy:

Plasma Vitamin D Deficiency Is Associated With Poor Sleep Quality and Night-Time Eating at Mid-Pregnancy in Singapore (2017)

Conclusion: A study of 1,152 pregnant women found that those who were vitamin D-deficient had higher incidences of poor sleep quality compared to women with sufficient vitamin D levels.


A Randomized Controlled Trial of Vitamin D Supplementation on Perinatal Depression: In Iranian Pregnant Mothers (2016)

Conclusion: This randomized control trial study split 169 pregnant Iranian women in their third trimester into two groups. One group received a placebo, the other received 2,000 IU of vitamin D3 daily for the duration of their pregnancy. Compared to the placebo group, the mothers receiving vitamin D had higher vitamin D levels and lower depression scores during the last month of pregnancy and the two months after childbirth. “The present trial showed that consuming 2000 IU vitamin D3 daily during late pregnancy was effective in decreasing perinatal depression levels.” Alarmingly, this study also found that 72% of the mothers were suffering from vitamin D-deficiency at baseline.
Note: much research has shown that 2,000 IU of vitamin D3 is inadequate for adults who don’t get much unprotected sun exposure. One wonders how much better the depression scores would have been with 5,000 IU of vitamin D daily.


The Impact of Maternal Vitamin D Status on Offspring Brain Development and Function: a Systematic Review (2015)

Conclusion: Big overview of all the research showing how crucial vitamin D is during fetal development for proper brain development and how vitamin D-deficiency in utero has been linked to multiple sclerosis, schizophrenia, diabetes, autism, depression, impaired speech and language development, and behavioral impairments including problems with anxiety, learning, memory, and impulse control.


Maternal Vitamin D Deficiency Alters Fetal Brain Development in the BALB/c Mouse  (2015)

Conclusion: Like many other similar studies, vitamin D-deficiency was shown to impair fetal neurodevelopment in mice.


Prenatal Vitamin D and Dental Caries in Infants (2014)

Conclusion: 207 mother-infant pairs were evaluated for vitamin D levels and dental caries in the children. The mothers had their vitamin D levels tested during pregnancy and then the infants were evaluated 1-2 years later on. The vitamin D levels of the expecting mothers were very bad with 90% having levels below the recommended minimum, 32% of them having levels below 14 ng/ml, and only 12% having levels above 30 ng/ml. The mothers who were tested during winter had much lower levels than the mothers who were tested during summer. Enamel hypoplasia was found in 22% of the infants and 36% were found to have dental caries (which correlates closely with the percentage of mothers badly deficient in vitamin D). Mothers of infants with dental caries had much lower prenatal vitamin D levels.


Vitamin D in Fetal Development: Findings From a Birth Cohort Study (2014)

Conclusion: This study examined 901 mother-child pairs to see what relationship existed between the mother’s vitamin D levels 18 weeks into a pregnancy and the health of the child later in life. The researchers found that maternal vitamin D-deficiency was “associated with impaired lung development in 6-year-old offspring, neurocognitive difficulties at age 10, increased risk of eating disorders in adolescence, and lower peak bone mass at 20 years.” The study also found associations between maternal vitamin D-deficiency and speech problems and autistic behavior later in life for the child.


Maternal Vitamin D Status and Infant Outcomes in Rural Vietnam: A Prospective Cohort Study (2014)

Conclusion: This study measured the vitamin D levels of 960 pregnant Vietnamese women at 8-months into their pregnancies, then six months later the cognitive, motor, and speech development of the babies was examined. Babies born from vitamin D-deficient mothers had reduced language development compared to babies born from mothers with higher vitamin D levels during pregnancy.


Maternal Serum Vitamin D Levels During Pregnancy and Offspring Neurocognitive Development (2012)

Conclusion: A 17-year study of 743 mother-child pairs found that children from mothers with low vitamin D levels during pregnancy went on to have almost double the chance of suffering language difficulties and impairment compared to children born from mother with adequate vitamin D levels during pregnancy.


Gestational Exposure to Urban Air Pollution Related to a Decrease in Cord Blood Vitamin D Levels (2012)

Conclusion: A study of 375 mother-newborn pairs in Poitiers, France and Nancy, France found that pregnant women living in Nancy, with it’s higher air pollution and higher latitude, are more likely to be vitamin D-deficient and give birth to vitamin D-deficient newborns – due to the air pollution blocking the UVB light necessary for cutaneous vitamin D synthesis, the higher latitude of Nancy providing less UVB, and higher air pollution making people more reluctant to go outside. 86% of all newborns in the study had insufficient vitamin D levels and 28% were severely deficient. Infants born in summer had the highest vitamin D levels, followed by infants born in autumn and spring, with infants born during winter having the lowest vitamin D levels.


Vitamin D Status and Periodontal Disease Among Pregnant Women (2011)

Conclusion: A case-controlled study analyzing 117 pregnant women with periodontal disease found that they had significantly lower vitamin D levels compared to 118 healthy controls.


Maternal Vitamin D Deficiency Is Associated with Bacterial Vaginosis in the First Trimester of Pregnancy (2009)

Conclusion: In a prospective study involving 469 pregnant women, those who were vitamin D deficient had more than double the rates of bacterial vaginosis compared to the women with adequate vitamin D levels.


Association Between Vitamin D Deficiency and Primary Cesarean Section (2009)

Conclusion: This study from a Boston Hospital found that women with lower vitamin D levels are more likely to require a cesarean section than mothers with higher vitamin D levels.
“Women who were severely vitamin D deficient [25(OH)D <37.5 nmol/liter] at the time of delivery had almost 4 times the odds of cesarean birth than women who were not deficient.”
Women with the highest serum 25(OH)D had the lowest probability of requiring a cesarean section.”


Association Between Vitamin D Deficiency and Primary Cesarean Section (2008)

Conclusion: 253 women who had recently given birth were analyzed. Those with lower vitamin D levels had a higher rate of cesarean sections compared to mothers with higher vitamin D levels. “Vitamin D deficiency was associated with increased odds of primary cesarean section.”


Maternal Intake of Vitamin D During Pregnancy and Risk of Recurrent Wheeze in Children At 3 y of Age (2007)

Conclusion: 1194 mother-child pairs in Massachusetts were analyzed. It was found three years later that the children from mothers with the highest vitamin D intake during pregnancy had the lowest risk of developing a recurrent wheeze.


Maternal Vitamin D Deficiency Increases the Risk of Preeclampsia (2007)

Conclusion: In a study of 275 pregnant women, mothers with lower vitamin D levels were much more likely to develop preeclampsia and, in addition to many other potential health problems arising from preeclampsia, newborns from preeclamptic mothers tended to have insufficient vitamin D levels.


Vitamin D Deficiency in a Healthy Group of Mothers and Newborn Infants (2007)

Conclusion: 40 mother-baby pairs were tested for vitamin D deficiency. 50% of the mothers and 65% of the babies were deficient. There is a strong correlation between maternal vitamin D levels and vitamin D levels of newborn infants.


High Prevalence of Vitamin D Insufficiency in Black and White Pregnant Women Residing in the Northern United States and Their Neonates (2007)

Conclusion: A study of pregnant women in Pittsburgh found that roughly 50% of them, and later their babies, were vitamin D insufficient.


Maternal Vitamin D Depletion Alters Neurogenesis in the Developing Rat Brain (2007)

Conclusion: Read the title


Developmental Vitamin D Deficiency Alters Brain Protein Expression in the Adult Rat: Implications for Neuropsychiatric Disorders (2007)

Conclusion: This study found that rat pups born from vitamin D-deficient mothers suffered from dysregulation of 36 different brain proteins.


Maternal Vitamin D Intake During Pregnancy and Early Childhood Wheezing (2007)

Conclusion: 2000 healthy pregnant women were enrolled in this study examining the effect of maternal vitamin D levels on the respiratory health of the child five years later. When the children were followed up with 5 years later, those born from mothers who had higher vitamin D levels during pregnancy were and had been suffering fewer wheezing and asthma symptoms compared to children born from mothers with lower vitamin D levels during pregnancy. “In summary, we report an inverse association between maternal vitamin D intake in pregnancy and risk of recurrent wheezing in 5-y-old children.”


Prospective Study Of Maternal Intake Of Vitamin D During Pregnancy And Risk Of Wheezing Illnesses In Children At Age 2 Years (2006)

Conclusion: 1,306 mother-child pairs were analyzed and it was found that higher “maternal vitamin D intake was associated with lower childhood risks of any wheeze” or asthmatic symptoms in their child by age two.


Developmental Vitamin D3 Deficiency Alters the Adult Rat Brain. (2005)

Conclusion: This study found that rat pups who suffer stunted brain development from fetal vitamin D-deficiency continue to exhibit this stunted brain development into adult age.


Vitamin D3 and Brain Development (2003)

Conclusion: This is an overview of a study in which the brains of rat pups born from vitamin D-depleted mothers and vitamin D-sufficient mothers were compared. The vitamin D-depleted rat pups developed “substantially” different brains compared to those with decent vitamin D levels. The depleted pups had brain hemispheres that were longer, but thinner. They also had thinner neocortexes, different rates of brain cell mitosis and apoptosis, radically different ventricular volume, and differences in neurohormone expression.


A Systematic Review and Meta-Analysis of Northern Hemisphere Season of Birth Studies in Schizophrenia (2003)

Conclusion: Schizophrenics tend to be born more in winter and spring compared to other seasons, when vitamin D-creating UVB radiation is less available. They also tend to be born more in latitudes farther away from the equator, which get less UVB radiation.


Low Maternal Vitamin D as a Risk Factor for Schizophrenia: A Pilot Study Using Banked Sera (2003)

Conclusion: “Low levels of maternal vitamin D may be associated with an increased risk of schizophrenia.”


Use of Cod Liver Oil During Pregnancy Associated with Lower Risk of Type 1 Diabetes in the Offspring (2000)

Conclusion: Norway study examining 85 type-1 diabetic subjects and 1,071 non-diabetic controls found that mothers supplementing with dietary vitamin D during pregnancy resulted in their offspring enjoying a lower risk for developing type-1 diabetes.


Maternal Consumption of a Low Vitamin D Diet Retards Metabolic and Contractile Development in the Neonatal Rat Heart (1995)

Conclusion: In a randomized control trial with rats, low maternal intake of vitamin D resulted in offspring with smaller hearts compared to offspring from mothers with higher vitamin D intake.


Mild Mental Retardation in Black and White Children in Metropolitan Atlanta: A Case-Control Study (1995)

Conclusion: This study of 893 children in Atlanta, Georgia, U.S. (330 mildly retarded kids and 563 normal controls) found that the rate of mental retardation in black children is nearly double that of white children. Although this study did not explore vitamin D as a factor, it is proven and well-documented that vitamin D is a crucial factor in brain development in utero and during childhood and there is also an overwhelming amount of evidence that blacks disproportionately suffer from vitamin D-deficiency and vitamin D-deficiency-related diseases and disorders due to the high amount of melanin in their skin partially or totally preventing cutaneous vitamin D synthesis from sunlight. It is also well-documented that people with mental disabilities and mental disorders tend to have lower vitamin D levels or have been born from and breastfed by mothers with poor vitamin D levels, and that vitamin D plays a very large role in producing optimal cognitive performance throughout life.
Also see: Health Studies Regarding Skin Color, Vitamin D, and Racial Health Disparities


Vitamin D Supplements Enhance Weight Gain and Nutritional Status in Pregnant Asians (1981)

Conclusion: In a randomized control trial of pregnant Asian women living in Britain, the mothers receiving vitamin D supplementation gained weight at a faster rate in their third trimester and had heavier babies.


Vitamin D Supplements in Pregnant Asian Women: Effects on Calcium Status and Fetal Growth (1980)

Conclusion: In a double-blind, placebo-controlled experiment involving 126 pregnant Asian women in their last trimester, those given 1000 IU of vitamin D2 gained weight faster and gave birth to bigger babies with adequate vitamin D levels and slight skeletal development differences compared to the placebo group.


Also see vitamin D studies regarding


Child Development


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