It absolutely makes sense that a good diet before and during pregnancy is associated with better pregnancy outcomes, including the risk for miscarriage.
Researchers at the University of Birmingham reviewed 20 studies (for a total of 63,838 women) and found that a good diet with healthy foods (both preconception and during pregnancy) is linked to a lower chance of miscarriage. On the other hand, a diet high in processed foods was associated with a doubling of miscarriage risk. Interestingly, higher intake of fried foods and a lower intake of chocolate is also associated with higher miscarriage odds.
What is a "good diet" linked to lower risk of miscarriage? One that is rich in fruits, vegetables, dairy, eggs, and seafood. A high intake of fruits was linked to 61% reduction of miscarriage risk, high intake of vegetables had a 41% reduction, dairy was linked to a 37% reduction, and consumption of eggs had a 19% reduction. Seafood (fish) had a 19% reduction.
Hmmm.... overall the results sound like Mediterranean-style or healthy Nordic foods diets are beneficial. By the way, the researchers were unable to draw any conclusions regarding meat, red meat, white meat, fat, and oil.
There are many reasons for the lower rate of miscarriage with a healthy, whole foods diet: from an increased intake of all sorts of nutrients (vitamins, minerals, flavanols, etc.), rich in anti-oxidants, less oxidative stress, lower rates of inflammation, boosts the immune system, to feeding beneficial microbes in our gut microbiome.
Fun fact: the developing fetus can taste the foods the mother eats.
From Medical Xpress: Diet high in fruit and vegetables linked to lower miscarriage risk
A preconception and early-pregnancy diet that contains lots of fruit, vegetables, seafood, dairy, eggs and grain may be associated with reducing risk of miscarriage, a new review of research suggests.
Researchers at the University of Birmingham analyzed 20 studies that explored women and birthing people's eating habits in the months before and shortly after conceiving a baby to see whether these studies showed evidence of association with a lower or higher chance of miscarriage.
Writing in the journal Fertility and Sterility the Tommy's National Center for Miscarriage Research team conclude that there is evidence to suggest a diet rich in fruit, vegetables, seafood, dairy products, eggs and grain reduces miscarriage risk.
These are foods which typically make up "healthy" well-balanced diets, with previous evidence showing that eating a well-rounded diet which is rich in vitamins and minerals during pregnancy is important.
The research review found that, when compared to low consumption, high intake of fruit may be associated with a 61% reduction in miscarriage risk. High vegetable intake may be associated with a 41% reduction in miscarriage risk. For dairy products it is a 37% reduction, 33% for grains, 19% for seafood and eggs.
However, a whole diet containing healthy foods overall, or foods rich in antioxidant sources, and low in pro-inflammatory foods or unhealthy food groups may be associated with a reduction in miscarriage risk for women.
A diet high in processed food was shown to be associated with doubling of miscarriage risk.
The studies included in the analysis focused on the peri-conception period—a period before and during the first three months of pregnancy. Data collected from a total of 63,838 healthy women of reproductive age was included, with information on their diets typically collected through food frequency questionnaires for each study.
"Yet nearly 50% of early pregnancy losses remain unexplained and in the absence of a cause, parents often turn to their healthcare providers for guidance on the best ways to be as healthy as possible and reduce the risk of future miscarriages.
"There's a growing body of evidence to show that lifestyle changes—including changes to diet, stopping smoking and not drinking alcohol—before conceiving and in your pregnancy's early stages—may have an impact.