I saw this ad on the tube:
And was struck by the types of claims made:
- Most trusted by mums
- Brand midwives recommend most
- No 1 pregnancy supplement brand
- Award for innovation in vitamins research
None of these is a scientific claim relating to an actual improved pregnancy/birth outcome. Indeed, Vitabiotics have had several of their adverts banned by the ASA for making unsubstantiated medical claims. See here, here, and here.
This page on their website has graphics corresponding to these claims, with links to the sources, as well as to the British Journal of Nutrition which published a paper that is the source of Pregnacare’s most scientific-sounding claim that:
…landmark in research was achieved … showing that Pregnacare tablets reduced the number of small-for-gestational-age (SGA) infants (low birth weight for time of birth) relative to the placebo.
The study of over 400 newly pregnant women … was the first ever reporting of clinical findings … showing that supplementing with a specific multivitamin supplement helps reduce the number of SGA infants born.
Except it’s not an actual working link, just a graphic which has the same visual appearance of the real links during a mouseover. I tracked down the paper because I had nothing better to do on a Monday night.
The researchers tried to recruit 2,385 socially and economically deprived mostly immigrant pregnant women in Hackney, East London. Only 402 subsequently participated (for example >10% of the sample were unable to speak English and therefore could not give consent). The 402 were given Pregnacare or a placebo tablet, but most dropped out leaving only 150 mothers who took the tablets regularly. This is the outcome:
The intention-to-treat analysis shows no difference in SGA numbers. There is in those fully compliant, and although that is in favour of Pregnacare, those receiving treatment were more likely to have a low birth weight child (even after a longer gestation period) – which is a more serious issue. (See this v this).
As far as I can see, after 1 hour of my life that I’m not getting back, giving vitamins to a multi-ethnic group of low-income pregnant women, of which 72% had a vitamin D deficiency to begin with, “may,” in the smallest print showing on the advert, “benefit those with nutritionally inadequate diets”. No shit. But if you’re short of time, pregnant, and read “Pregnacare” you may well take the cognitive shortcut that these tablets will help you take good care during your pregnancy.