Vitamin A in Pregnancy

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The measurement of Vitamin A was changed from the old ‘iu’(international units), to European measures of ‘mcg’ or micro-grams.

These two measures do not reflect exactly the same thing. The international units used to give the potency of the source (which can vary with the oil soluble vitamins). The mcg only gives the weight. So we provide both measures, for your information, below to avoid confusion, as you may find either in papers, on the internet, or on tubs of supplements.

For pregnancy, Foresight advises 2,100iu (722mcg) – 5,000iu (1,501mcg)

Vitamin A excess can be dangerous in pregnancy, but so can Vitamin A deficiency. The dangers of Vitamin A deficiency have been too little understood or published over the last decade.

Scientific advice on what constitutes excess Vitamin A is very variable. The Denner Report quoted 10,000iu (3,3003mcg). Professor Merlyn Werbach of the University of California (arguably the world authority on fetal nutrition) says 40,000iu (12,012mcg). An Australian source gives 25,000(7,507mcg).

Foresight programmes are always very conservative, as the obvious approach is to give enough to avoid any danger of deficiency, while giving very little more than this, to be sure of staying within the safe limit.

The maximum we usually give is:

  • 2 x Foresight Vitamin Supplements = 2100 iu (722 mcg)
  • 4 x Selenium ACE = 2000 iu (687 mcg)
  • Total Given = 4100 iu (1409 mcg)

The minimum we give is the 2100iu (722mcg) present in two Foresight Vitamins.

Even our most generous programmes give less than half the most conservative upper limit, which was the Denner Report’s 100,000iu (3,303mcg).

It is interesting to note in this context that during the war (when despite rationing, most people’s diet was more nutritious than that of today), the Government decreed all pregnant women should have “a teaspoonful of cod liver oil” daily. It is hard to assess the amount of Vitamin A, as a lot would have depended on the size of the teaspoon, but it is likely to have been in the region of 5,000iu (1,501mcg). At the present time in the USA, pregnant women are given 5,000iu (1,501mcgVitamin daily. In some areas of Australia, they are given 10,000iu (3,303mcg). UNESCO campaigns for funding to give Vitamin A to pregnant mothers in the Third World to stop babies from being born blind.

Vitamin A deficiency deformities in experimental animals have been recorded by Dr. Isobel Jennings of Cambridge, and by Dr. Weston Price of California.

Isobel Jennings, MRCVS, Cambridge Fetal animal studies by a veterinary pathologist.

Vitamin A


  • Cranial abnormalities
  • Cleft Palate
  • Hare Lip
  • Eye defects
  • Hydrocephalus
  • Spina Bifida
  • Exencephalus


  • No eyes
  • Micropthalmias
  • Blindness
  • Cardiovascular Anomalies
  • Urogenital Anomalies
  • Diaphragmatic Hernia
  • Hydrospadias
  • Cryptorchidism

Dr Weston Price of California, lists Vitamin A deficiency as causing problems with the development of the eyes, ranging from impaired sight, to blindness, to being born with no eyes (anopthalmia). Dr Price also reported damage to the nerves leading to the ears, and therefore impaired hearing, ranging to total deafness. Prolongation of the gestation period and long and difficult labour were reported in rats. Calves were reported as being born small and less likely to survive. Farm animals generally were reported to have had less successful reproduction and lactation, and less resistance to infection, where Vitamin A levels were less than optimum.

Lack of Vitamin A in the diet of pigs resulted in ‘extreme in coordination and spasms’, and a tendency to abortion and farrowing dead piglets. Another researcher quoted by Price showed that lack of Vitamin A produced disturbances in ‘oestrus and ovulation’, leading to sterility.

Professor Hale of the Texas Agricultural Experimental Station found that as well as piglets being born blind, “depriving pigs of Vitamin A for a sufficient period produced severe nerve involvements, including paralysis and spasms so the animals could not rise to their feet” (Would this be relevant to cerebral palsy in the human infant?)

Professor Hale also found that if the sire of any species were deprived of Vitamin A, he would become sterile. Disturbances of the development of the upper and lower jaw and tooth decay were also reported in humans whose diets lacked Vitamin A.

In the 35 years of running Foresight we have not seen any of the deformities listed above in ‘our’ babies. I would not therefore be tempted to supplement above 5,000iu (1,501mcg), although you could probably take up to 10,000iu (3,303mcg~) without harm.

However, I think there could be case made out for a little more with the multiple births, especially triplets.

It is not advisable to take less than 2,100iu (722mcg) as this could lead to the risk of serious malformations. 45,000 babies (1 baby in 16) are now born in Britain with malformations annually. The largest groups include those with malformations listed above which are proven by scientific research to be due to Vitamin A deficiency. This is a tragedy probably greater than the thalidomide debacle, and it should be more easily preventable, as all the research is out there, and has been for many years.

We continue to advise you to take between 2,100iu (722mcg) and 5000iu (1,501mcg) daily, before and throughout pregnancy.

You are welcome to take this information to your GP, midwife or health visitor if this would be helpful. If they (or you) have any scientific papers that contradicts what I am saying, or supports it, I would be particularly grateful to be sent a copy, as I would be very interested to study them.

  • References
  • The Denner Report, London, HMSO (c1990)
  • Werbach., M., “Nutritional Influences on Illness”, Third Line Press, California, USA(1988)
  • Naish, F., and Roberts, J., “Better Babies”, Random House, Australia, P57., (1966)
  • Jennings, I.W.., “Vitamins in Endocrine Metabolism”
  • William Heinemann Medical Press, pp130-131 (1972)
  • Price, W.A., “Nutritional and Physical Degeneration”
  • The Price Pottinger Nutrition Foundation, LA Mesa, California, USA (1945)
  • Hale, F., “Pigs Born Without Eyeballs”, J Herad 24, pp 105-106 (1935)

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"We came across Foresight as we decided to try for our first child (we had previously had a miscarriage). We understood it as a different approach to healthy living and have kept on, despite not planning any more children, a lot of your principles and advice in our daily routine. We get our fresh produce (fruit, veg, dairy, eggs, meat) delivered from local organic farms and have not found our bills going up, as we stick to what we get! I threw aluminium cookware out and replaced it for glass or stainless steel and cut out artificially composed foods. We also did hair analysis and have been filtering our water for almost 4 years now (we have now invested in an osmosis filter) as our heavy metals were quite high.

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