The vegan diet has become more popular in the last few years, but could being vegan be dangerous during pregnancy? Well it seems that may well be the case. A recent study posted in Acta Obstetricia et Gynecologica Scandinavica suggests so, and it isn’t the first of it’s kind to raise these concerns.
The Study: Adherence to Plant-Based Diets and Pregnancy Outcomes
The study was conducted by researchers aimed to investigate whether following specific plant based diets had any influence on pregnancy or birth outcomes.
The scientists analysed self reported dietary intake and pregnancy data from the Danish National Birth Register between 1996 and 2002. This included nearly 67000 women.
The participants were divided into four groups based on their reported dietary preferences: vegetarians who consume fish and poultry (which one would debate whether someone who eats chicken is a vegetarian, however that’s another matter) vegetarians who consume dairy and eggs (lacto/ovo vegetarians, or as most people would call them, actual vegetarians), vegans, and omnivores.
The researchers then examined the rates of pregnancy complications, such as preeclampsia, as well as the birth weights of the newborn babies.
Findings: Higher Risk of Preeclampsia and Lower Birth Weight
Of course the overwhelming majority (65,872) were omnivores. A smaller number of individuals identified as fish/poultry vegetarians (666), lacto/ovo vegetarians (183), and vegans (18).
This of course does present some issues with the findings due to the low sample size.
The research team found that pregnant women who adhered to a vegan diet had a higher risk of developing preeclampsia and an increased chance of giving birth to babies with lower birth weights compared to those following an omnivorous diet.
Whilst this sample is relatively small, it’s not the first study to record lower birth weights from vegan mothers.
Protein Intake and Micronutrient Deficiencies
Further analysis of the participants' dietary intake revealed that protein consumption was lower among lacto/ovo vegetarians (13.3%) and vegans (10.4%) compared to omnivorous participants (15.4%).
And as you would expect the intake of essential micronutrients was significantly lower among those following a vegan diet.
Now it’s also worth mentioning that the dates are a potential issue as education around vegan supplement requirements was not as good in the 90s as it is now. It could still be better, particularly around certain plant based omega sources not being processable by humans, but that is another issue.
And of course with supplementation several of these deficiencies in protein and micronutrients could be resolved.
Especially as the study's authors suggest that the risks of preeclampsia and lower birth weight associated with a vegan diet may be attributed to these lower protein intakes and specific nutrient deficiencies.
Limitations and Cautionary Interpretation
The low number of actual vegans, and the time the data was collected, does as we’ve mentioned raise some concerns over the validity of the study.
Consistency with Recent Studies On Veganism During Pregnancy
However the study's authors highlight that the associations between following a vegan diet during pregnancy and lower birth weight are consistent with more recent studies.
These findings suggest that there may be a genuine relationship between a vegan diet and certain pregnancy complications and birth outcomes.