Patients, Families & Visitors Patient & Visitor Resources Low Vitamin D Levels Early in Pregnancy Associated with Lower Birth Weights, Pitt Research Finds PITTSBURGH, Dec. 19, 2012 – Women deficient in vitamin D early in their pregnancies are more likely to deliver babies with lower birth weights, University of Pittsburgh Graduate School of Public Health research reveals. The study, funded by the National Institutes of Health, will be reported in the January print edition of the Journal of Clinical Endocrinology & Metabolism and is now available online. Co-authors include Hyagriv N. Simhan, M.D., Pitt School of Medicine and Magee-Womens Hospital of UPMC; and Mark A. Klebanoff, M.D., M.P.H., The Ohio State University College of Medicine and Nationwide Children’s Hospital.High Doses of Vitamin D May Cut Pregnancy Risks Study Shows 4,000 IU a Day of Vitamin D May Reduce Preterm Birth and Other Risks May 4, 2010 -- Women who take high doses of vitamin D during pregnancy have a greatly reduced risk of complications, including gestational diabetes, preterm birth, and infection, new research suggests.
Based on the findings, study researchers are recommending that pregnant women take 4,000 international units (IU) of vitamin D every day -- at least 10 times the amount recommended by various health groups. Women in the study who took 4,000 IU of the vitamin daily in their second and third trimesters showed no evidence of harm, but they had half the rate of pregnancy-related complications as women who took 400 IU of vitamin D every day, says neonatologist and study co-researcher Carol L. Wagner, MD, of the Medical University of South Carolina. Wagner acknowledges the recommendation may be controversial because very high doses of vitamin D have long been believed to cause birth defects. "Any doctor who hasn't followed the literature may be wary of telling their patients to take 4,000 IU of vitamin D," she says. "But there is no evidence that vitamin D supplementation is toxic, even at levels above 10,000 IU." Fewer Complications With High Vitamin D Doses Most prenatal vitamins have around 400 IU of vitamin D, and most health groups recommend taking no more than 2,000 IU of the vitamin in supplement form daily.
Wagner says it took months to get permission to do a study in which pregnant women were given doses of the vitamin that were twice as high as this. The study included about 500 women in Charleston, S.C., who were in their third or fourth months of pregnancy. The women took 400 IU, 2,000 IU, or 4,000 IU of vitamin D daily until they delivered. Not surprisingly, women who took the highest doses of vitamin D were the least likely to have deficient or insufficient blood levels of the vitamin, as were their babies. These women also had the lowest rate of pregnancy-related complications. Compared to women who took 400 IU of vitamin D daily, those who took 4,000 IU were half as likely to develop gestational diabetes, pregnancy-related high blood pressure, or preeclampsia, Wagner says. They were also less likely to give birth prematurely. The research was presented over the weekend at the annual meeting of the Pediatric Academic Societies in Vancouver, British Columbia.
Infants with very low vitamin D levels are at increased risk for soft bones, or rickets -- a condition that is now rare in the U.S. But over the last decade, more and more studies suggest that vitamin D also protects against immune system disorders and other diseases, Wagner says. Fortified milk and fatty fish are common food sources of vitamin D, but most people get only a small fraction of the vitamin D they need through food, Wagner says. Instead, the body makes vitamin D from sunlight. But even in sunny climates like Charleston, few people are now getting adequate levels of vitamin D from sun exposure. At the start of the study, deficient or insufficient levels of vitamin D were seen in 94% of the African-American women, 66% of Hispanic women, and 50% of white women who participated. Vitamin D and Pregnancy: Is More Better? University of Rochester professor of pediatrics Ruth Lawrence, MD, has been recording vitamin D levels in new mothers and their infants for three years.
She did not take part in the new study. Lawrence, who chairs the breastfeeding committee of the American Academy of Pediatrics, says exclusively breastfed babies whose mothers have low vitamin D levels and who don't take vitamin supplements are most likely to be deficient. "It is clear that both for mothers and their babies, vitamin D levels are low," she tells WebMD. "This is true in northern areas like Rochester and in sunny climates like Charleston." Lawrence sees no problem with the recommendation that women take 4,000 IU of vitamin D daily during pregnancy, although she says the impact of high doses of vitamin D on pregnancy-related complications remains to be proven. "Four thousand IU may sound outrageous to some, but I believe it is really not unreasonable," she says. "We have been searching for the causes of preeclampsia and premature birth for many years. It is reassuring that the risk of these complications are lower for women taking extra vitamin D, but it is premature to say it is the cause."
The independent health policy group the Institute of Medicine recommends 200 IU to 400 IU of vitamin D a day for everyone, including pregnant women, but this recommendation is under review. Revised guidelines are expected late this summer.The IP address used for your Internet connection is part of a subnet that has been blocked from access to PubMed Central. Addresses across the entire subnet were used to download content in bulk, in violation of the terms of the PMC Copyright Notice. Use of PMC is free, but must comply with the terms of the Copyright Notice on the PMC site. For additional information, or to request that your IP address be unblocked, For requests to be unblocked, you must include all of the information in the box above in your message.Your body needs vitamin D to maintain proper levels of calcium and phosphorus, which help build your baby's bones and teeth.Vitamin D deficiency is common during pregnancy. Inadequate vitamin D can lead to abnormal bone growth, fractures, or rickets in newborns.
Some studies link vitamin D deficiency to a higher risk of pregnancy complications such as gestational diabetes, preeclampsia, preterm birth, and low birth weight, but more research is needed to confirm these links.The symptoms of a vitamin D deficiency can be subtle. They may include achy muscles, weakness, bone pain, and softened bones, which may lead to fractures.You can also have a vitamin D deficiency without any symptoms. And if that happens while you're pregnant, your baby can suffer a deficiency, too.Vitamin D dosage is a topic of debate. The Institute of Medicine currently recommends that all women – whether or not they're pregnant or breastfeeding – get 600 international units (IU) of vitamin D or 15 micrograms (mcg) each day.But many experts believe that 600 IU isn't nearly enough. The Linus Pauling Institute, for example, recommends all adults take 2,000 IU of supplemental vitamin D each day. The Endocrine Society says 600 IU may be enough, but some people – including pregnant and breastfeeding women – may need 1,500 to 2,000 IU of vitamin D.In 2015, the American College of Obstetricians and Gynecologists stated that more safety research is needed before the organization would recommend more vitamin D than what's in a standard prenatal vitamin.
Ask your healthcare provider for advice about how much vitamin D you need during pregnancy.Fish liver oil, fatty fish, and eggs all contain vitamin D. But not many other foods contain vitamin D naturally, so a lot are fortified with this important vitamin. Be sure to check labels: Some cheeses, yogurts, and cereals are fortified while others aren't. (All milk is vitamin D fortified.)Here are some of the best food sources of vitamin D:Maybe. Most prenatal vitamins only contain 400 IU (10 mcg) of vitamin D, and it's difficult to get sufficient vitamin D from foods alone, even when you choose fortified foods.Since the skin uses the sun's rays to produce vitamin D, some experts recommend limited sun exposure, while others caution against it without the protection of sunblock and clothing. Exposure to the sun's ultraviolet [UV] rays intensifies the pigment changes that cause irregular skin darkening in pregnant women, so most doctors recommend that pregnant women protect themselves from the sun and get their vitamin D from food or supplements.