How much vitamin D do you need to supplement with if you’re pregnant? There are no easy answers to that question.
The American Pregnancy Association references the benefits of taking 4,000 IU a day, something supported by a 2012 study. According to the National Institutes of Health, the recommended daily allowance (RDA) for adult women is 600 IUs daily—including women pregnant and lactating.
“Different bodies, have different recommendations for the amount of vitamin D that pregnant and breastfeeding women require and infants,” said Pegah Jalali, a dietitian from New York.
That said, more research is coming in that vitamin D is a must for us—especially when expecting. Getting enough was recently linked to conceiving and giving birth to a healthy child. And a recent meta-analysis of existing studies in JAMA Pediatrics examined 24 clinical trials including 5,405 participants. It found that women who took 2,000 IU or less each day had a 55 percent lower chance of their infant being underweight and a 65 percent lower chance of fetus or infant mortality.
How Much Vitamin D Do Mamas Need?
So what’s the verdict? How much vitamin D should you take if you’re expecting?
Get your levels tested first instead of focusing on IUs. Then pay attention to how much a supplement packs.
Based on pharmacokinetics of vitamin D during pregnancy, the evidence supports that women should take the amount of vitamin D to achieve a total circulating 25(OH)D concentration of at least 40 ng/mL (100 nmol/L), which is achieved in the majority of women by taking 4,000 IU per day, said Carol Wagner, M.D., a professor at the Medical University of South Carolina.
Be on the safe side and get your blood levels checked first—then let your physician tell you how much you should supplement with a day, say Lyssie Lakatos and Tammy Lakatos Shames, registered dietitians from New York. That’s because everyone’s bodies differ as far as how they metabolize vitamin D, as well as how much of the vitamin they get from their diet.
And remember that consuming too much vitamin D can damage the heart, blood vessels and kidneys.
That said, your run-of-the-mill prenatal vitamin probably doesn’t have you covered, they noted.
“If women are taking a prenatal vitamin, they often do meet the recommendations,” the twin dietitians added.
Jalali said many women are deficient in vitamin D prior to becoming pregnancy—another reason to get levels checked with a blood test.
Vitamin D is a fat-soluble vitamin so it needs fat to be absorbed. Unfortunately most gummy or tablet vitamins do not have any fat, and many people take their vitamins in the morning on an empty stomach or at night on an empty stomach.
“Without any fat, you will not absorb the vitamin D effectively,” she explained. Jalali recommends a vitamin D oil drop, because they don’t contain other additives and absorb well.
When you talk to your doctor about supplementing, ask about calcium too.
“Most prenatal vitamins do not have enough calcium. You definitely do not need extra calcium for absorption of vitamin D but you need to get enough calcium to meet your calcium needs,” she added. “Vitamin D helps with calcium absorption, not the other way around.”