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# Higher Dose of Vitamin D May Benefit Pregnant Women
- URL: https://www.foodconsumer.org/higher_dose_of_vitamin_d_pregnant_women_1103160434/
- Published: 2016-11-03T17:32:00.000Z
- Updated: 2026-09-22T16:31:08.000Z
- Description: USDA and UC Davis scientists report in The Journal of Nutrition that a vitamin D dose above the 400 IU common in prenatal supplements may reduce inflammation in pregnancy. Surveys suggest deficiency affects up to 69 percent of pregnant American women.
- Author: Food Consumer
- Tags: Vitamins, Nutrition, #vivvo-import

ARS News Service  
Agricultural Research Service, USDA  
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## Higher Dose of Vitamin D May Benefit Pregnant Women

By [Sandra Avant,](http://www.ars.usda.gov/is/contacts.htm?ref=foodconsumer.org#Sandra)  
November 3, 2016

Vitamin D is essential for strong bones and overall health, but the amount our bodies make from sunlight exposure and obtain from foods is not always enough, particularly for pregnant women.

[U.S. Department of Agriculture](http://www.usda.gov/wps/portal/usda/usdahome?ref=foodconsumer.org) (USDA) and [University of California, Davis](https://www.ucdavis.edu/?ref=foodconsumer.org) (UC Davis) scientists have found that a higher dose of vitamin D supplement during pregnancy may reduce inflammation. Their findings were published in the November 2016 issue of [*The Journal of Nutrition*](http://jn.nutrition.org/?ref=foodconsumer.org).

| [![Photo: Link to photo information](https://storage.ghost.io/c/f5/c2/f5c28c07-f2c7-440d-8161-125a09d9bc91/content/images/2026/08/64995e0fc9d3bd384f4e1002300558360781093f.jpg)](https://www.ars.usda.gov/oc/images/photos/nov16/d3714-1/?ref=foodconsumer.org)A new ARS-UC Davis study indicates that expectant mothers may benefit from an additional dose of vitamin D supplement.*Click the image for more information about it.*                                                                                                     |
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| ![For further reading](https://storage.ghost.io/c/f5/c2/f5c28c07-f2c7-440d-8161-125a09d9bc91/content/images/2026/08/67b91d6a8a098121dec9cea8302ea484fcfb93de.gif) [Lowering the Risk of Infection with Grapes](https://www.ars.usda.gov/news-events/news/research-news/2016/lowering-the-risk-of-infection-with-grapes/?ref=foodconsumer.org) [Low Vitamin D Linked to Osteoarthritis in the Knee](https://www.ars.usda.gov/news-events/news/research-news/2015/low-vitamin-d-linked-to-osteoarthritis-in-the-knee/?ref=foodconsumer.org) |

The research team included [Charles Stephensen](https://www.ars.usda.gov/pacific-west-area/davis-ca/western-human-nutrition-research-center/immunity-and-disease-prevention-research/people/charles-stephensen/?ref=foodconsumer.org), with the USDA-Agricultural Research Service (ARS) [Western Human Nutrition Research Center](https://www.ars.usda.gov/pacific-west-area/davis-ca/western-human-nutrition-research-center/?ref=foodconsumer.org) (WHNRC) in Davis, California; Melissa Zerofsky, a former UC Davis doctorate student; and Bryon Jacoby, a maternal fetal medicine specialist affiliated with [UC Davis Medical Center](http://www.ucdmc.ucdavis.edu/medicalcenter/?ref=foodconsumer.org). Researchers wanted to find out whether vitamin D intake levels should be higher than those common in prenatal supplements—400 international units (IU).

Severe vitamin D deficiency can contribute to osteoporosis in adults and rickets (a condition of weakened bones) in infants and children. Recent surveys also suggest that vitamin D deficiency affects up to 69 percent of American pregnant women.

Higher vitamin D levels in a person's blood may protect against certain types of cancer, strengthen the immune system, reduce diabetes risk, and play a key role in suppressing inflammation. Reducing inflammation during pregnancy is important because inflammation is associated with high blood pressure, pre-eclampsia, premature delivery and low birthweight, according to Stephensen, research leader at WHNRC's [Immunity and Disease Prevention Research Unit](https://www.ars.usda.gov/pacific-west-area/davis-ca/western-human-nutrition-research-center/immunity-and-disease-prevention-research/?ref=foodconsumer.org).

In the ARS-UC Davis study, healthy women in their first trimester of pregnancy voluntarily consumed different doses of vitamin D daily. They took either a multivitamin supplement containing 400 IU vitamin D and a placebo pill, or a 400 IU vitamin D supplement and an additional 1600 IU vitamin D pill. Blood samples were analyzed for various forms of vitamin D and immune and inflammatory markers. The mothers' blood pressure and infants' birthweight were recorded.

The vitamin D dosage did not affect maternal blood pressure or infant birthweight. However, the higher daily dose, 2000 IU vitamin D, increased circulating vitamin D concentrations relative to the 400 IU per day. Higher blood vitamin D was correlated with lower circulating tumor necrosis factor-α (TNF-α), an immune substance typically associated with inflammation.

The scientists concluded that consuming 2000 IU vitamin D instead of 400 IU each day is more effective at increasing vitamin D status in pregnant women. They also found that higher levels of vitamin D increased the proportion of a specific subset of immune cells with anti-inflammatory properties that may prevent adverse effects of excess inflammation.

[ARS](https://www.ars.usda.gov/?ref=foodconsumer.org) is USDA's chief in-house scientific research agency.