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16 May 2016 - Nutraingredients - Prenatal vitamins may reduce risk of pregnancy loss by 55%

Stephen Daniells

FAB RESEARCH COMMENT:

As often happens, the dramatic headline given to this news article rather over-states the findings from this small study, and ignores the limitations pointed out in the article itself.

First -as this study design was purely observational, its findings can't be taken as evidence of a causal link between multivitamin use and pregancy outcomes. (Those taking multivitamins may have differed in other relevant ways from those who did not). In addition, the sample was both small and unlikely to be representative of the general population (344 couples who were actively trying to achieve a pregnancy - which might perhaps also help to explain why no associations with alcohol consumption were found). And the data on multivitamin use were all self-reported, with no information on the type of supplements used.

In fact, a recent Cochrane systematic review of randomised controlled trials addressing this question was also published earlier this month, involving 276,820 women (see Balogun et al 2016). This found no definitive evidence of reduced miscarriage risk from vitamin use in pregnancy (using many different types of 'active' and comparison supplements, each analysed separately as far as possible). However, they did find good evidence that using multivitamins + iron and folic acid reduced the risk of stillbirth.

Having said all that - abundant evidence already shows that malnutrition / poor diet can raise the risk for adverse pregnancy outcomes, which is why most public health guidelines recommend that mothers-to-be use a good multivitamin and mineral supplement, ideally from before conception.

Read the associated research here:
See also:
and for general information on nutrition and supplements during pregnancy:

Taking a prenatal multivitamin every single day during pregnancy may reduce the risk of losing the baby by 55%, compared to not taking a multivitamin, says a new study.

Data from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study, a prospective cohort that enrolled couples prior to conception, indicated that this risk reduction increased to 79% for adherence during early pregnancy.

“This strong protective effect for preconception multivitamin usage is somewhat consistent with findings from a preconception cohort of female Chinese textile workers, where women in the highest versus lowest quartile of vitamin B6 had a lower odds of pregnancy loss,” wrote the researchers, led by Germaine Buck Louis, PhD, from the National Institute of Child Health and Human Development, in Fertility and Sterility .

“Related support stems from previous studies that involved self-reported vitamin or folate usage and pregnancy loss. In a cohort of women with prospectively collected folate intake and self-reported pregnancy loss, women in the highest versus lowest quintile of folate intake had a 19% reduction in risk of loss.

“Collectively, these data are supportive of a beneficial association between vitamin usage and pregnancy loss.”

No differentiation was made between over-the-counter multivitamins and prescription prenatal vitamins, noted the researchers.

No surprises

Commenting independently on the study’s findings, Marlene Goldman, ScD, Professor and Director of the Division of Clinical Research in the Dept. of Obstetrics and Gynecology at Dartmouth-Hitchcock Medical Center, told us: “It would be reassuring if the data were supported by others but it certainly reinforces preconception recommendations .”

Dr Goldman added that, for her, there were no real surprises in the study’s findings, but she did point out some of the limitations, notably that this study relied on self-reported data, and that the link to vitamin use could be a marker for something else.

“Women who take vitamins are generally more health conscious,” said Dr Goldman. “They may be more rigorous with timing intercourse with ovulation, or they may be more likely to take pregnancy tests, and so on.”

Study details

Dr Buck Louis and her co-workers recruited 344 couples in 16 counties in Michigan and Texas to participate in their study, reflecting the societal shift from “I am pregnant” to “we are pregnant”. The women were aged between 18 and 40, and the men over 18. The couples were followed while they were trying to conceive and then for seven weeks post-conception.

The incidence of pregnancy loss among couples who achieved a recognized pregnancy during the LIFE Study was 28%, reported the researchers.

Age was a significant risk factor, with a great risk of pregnancy loss in women over 35. Caffeine consumption was also associated with pregnancy loss, particularly when more than two caffeinated beverages were consumed per day. On the other hand, the researchers did not observed an association between alcohol consumption and pregnancy loss after adjusting for other factors. This result was in contrast to those reported in other studies.

“Our data suggest that couples' lifestyles are associated with the risk of pregnancy loss, including during the preconception period, emphasizing the need for continued efforts to promote healthy lifestyles before pregnancy begins, that is, preconception guidance,” wrote Dr Buck Louis and her co-workers.

“Couples might continue to be advised that advanced age increases the risk of pregnancy loss and to limit caffeinated intake to fewer than 3 daily beverages irrespective of source and that women should continue to take daily multivitamins before and during pregnancy consistent with clinical guidance. Our findings are not intended to suggest substituting decaffeinated or caffeine-free beverages as a safer alternative, as we did not query couples on these products.

“Collectively, our findings are supportive of the need for ongoing efforts to ensure couples receive preconception guidance, and our findings await corroboration from other preconception couples-based cohorts to ensure that preconception guidance issued for the US population  is responsive to discoveries to the extent possible.”