You may have seen some disturbing headings from news articles on a recently published research study on vitamin D and pregnancy:

Jury Still Out on Vitamin D Supplements in Pregnancy     

https://www.medpagetoday.com/obgyn/pregnancy/69559
    
Insufficient evidence to guide recommendations on vitamin D in pregnancy 

https://eurekalert.org/pub_releases/2017-11/b-iet112717.php

The study was published in the British Medical Journal November 29, 2017 by Roth et al: 

Vitamin D supplementation during pregnancy: state of the evidence from a systematic review of randomised trials

http://www.bmj.com/content/359/bmj.j5237

The study reported: “We conclude that there is currently insufficient evidence to guide recommendations for prenatal vitamin D supplementation.”

The Vitamin D Society follow the recommendations and advice from 48 vitamin D scientists, doctors and researchers who recommend everyone, every man, woman and child, whether pregnant or not, should ensure that they optimize their vitamin D level by maintaining a vitamin D blood level of between 100-150 nmol/L (40-60 ng/ml). So the advice for pregnant women is the same as it is for all women.

Dr. John Cannell, Founder and Medical Director for the Vitamin D Council, has written and published this excellent response to the Roth paper in the BMJ:

http://www.bmj.com/content/359/bmj.j5237/rapid-responses

“Dr. Roth accurately writes that randomized controlled trial (RCTs) of vitamin D in pregnancy have shown conflicting results.  He also gives a number of reasons that may explain those negative trials. And, like a competent scientist, he opines that until RCTs show efficacy without toxicity, physiological doses of vitamin D should not be prescribed in pregnancy. Instead we should continue with the near homeopathic doses (10 – 15 mcg/day) that are now used in pregnancy. (I can't think of any other nutrient used in such meaningless doses but I'm sure they exist.)

However, if his standard were followed, we would not treat scurvy with vitamin C, prevent beriberi with thiamine, pellagra with niacin, or help prevent neural tube defects with folic acid, none of which have RCTs supporting such use. Physicians of the past addressed the pathological consequences of the inadequate intake of nutrients, not with more RCTs, but by applying common sense.

“Yesterday (11/29/17), yet another study (four to date) confirmed low levels of vitamin D during pregnancy are associated with a substantially increased risk of developing autism. (1)  Almost ten years ago the vitamin D/autism link exposed in detail (2), ten years during which time 134 additional such papers appeared and during which time hundreds of thousands children were condemned to autism. Similar, but fewer, studies exist for the substantial risk of developing multiple sclerosis in later life as well as most of the diseases of pregnancy. As Dr. Roth points out, the results of most of those studies were mixed. What he did not dwell on is the fact that "the dose makes the medicine." and the doses in almost all the studies he reviewed used 10 or 15 mcg/day, a dose that often does not result in meaningful changes in vitamin D status levels nor in preventing disease, (It is instructional to stop using IUs to measure the mass of vitamin D and move to the metric system. For example, 250 mcg is considered a small dose by many, while 10,000 IU is a large one without knowing they are the same dose.)

Two crucial points are missed with Roth's opinion. The first is that vitamin D is safe. If you think it dangerous at physiological adult doses (125-250 mcg/day), you are ignorant about its toxicology. (“Everything is toxic, nothing is without toxicity, the dose alone determines if something is toxic.) Since it is safe at these doses, one has to weigh the consequences of action vs. the inaction Dr. Roth advises. It seems to me, common sense dictates pregnant women should be supplemented now, not made the Guinea pigs of further RCTs.

Finally, there are stark differences between scientists and physicians. Scientists require definitive proof before a theorem is considered fact. In other words, beyond a reasonable doubt. But scientists do not treat patients, with few notable exceptions. Scientists do not take the Hippocratic Oath. The standard physicians used over history was to balance the known toxicity with the potential benefits and act accordingly. Physicians should ask their attorney if such a standard of treatment still exists and if they may be held to it in a courtroom.

Physicians have never required endless RCT for proof until very recently with the onset and misunderstanding of Evidence Based Medicine. Instead physicians have always, until recently, weighed the potential consequences of treatment vs. inaction, that is potential harm vs. potential benefit. If you weigh on the potential harm call for inaction side, you are reading a different vitamin D literature (now at 61,323 publications) than I am reading.

Physicians are required by law and ethics to act on the evidence known today, not what may be discovered in the future. If inaction persists, what are we going to say to parents of the children with autism or the women who develop MS in the future?  “Oh, I’m so sorry your child has autism but we decided to let scientists determine physician’s action instead medical tradition or common sense.”

1. Basheer S, et al. Vitamin D status of children with Autism Spectrum Disorder: Case-control study from India. Asian J Psychiatr. 2017 Dec;30:200-201.

2.Cannell J.J. Autism and vitamin D. Med Hypotheses. 2008;70(4):750-9.