What you eat during early pregnancy could affect miscarriage risk: study

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Our diet can affect many aspects of our health, but according to a new study, eating the right foods may also help to reduce the risk of miscarriages.

A new study published in the peer-reviewed journal Fertility and Sterility earlier this month reviewed 20 studies that looked at the eating habits of women and other people capable of carrying a baby in the months before and after conceiving, in order to see if these studies showed a clear impact of diet during early pregnancy.

What they found was that a diet rich in fruit, vegetables, seafood, dairy products, eggs and grain was overall correlated with a lower risk of miscarriage.

“Miscarriage is common, with estimates suggesting 1 in 6 pregnancies end in miscarriage, and there are many known causes, from problems with the baby’s chromosomes to infections in the womb,” Dr. Yealin Chung, a phD candidate with the University of Birmingham and the lead author of the study, said in a press release.

“Yet nearly 50 per cent of early pregnancy losses remain unexplained and in the absence of a cause, parents often turn to their health-care providers for guidance on the best ways to be as healthy as possible and reduce the risk of future miscarriages.”

Of the 20 studies researchers looked at, six had data that allowed for meta-analysis, spanning more than 13,000 participants in total.

A high intake of fruit marked the largest difference, researchers found, with high fruit intake associated with a 61 per cent reduction in miscarriage risk compared to those with a low fruit intake during.

Lots of vegetables in a pregnant person’s diet was correlated with a 41 per cent reduction in miscarriage risk, while high intake of dairy products came with a 37 per cent reduction of miscarriage. For grains, high intake reduced miscarriage risk by 33 per cent. Plenty of seafood and eggs came with a 19 per cent reduction in miscarriage risk.

These items are often found within what is considered a “healthy” diet, researchers note, and allowing for enough vitamins and minerals is important while the body is undergoing the new stress of pregnancy.

“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,” Chung said.

What constituted a “high intake” vs. a “low intake” varied between the types of foods as well as the specific studies included in the meta-analysis, which means this new study isn’t able to provide a clear recommendation for how many bananas you should be consuming in a week, for instance.

In two studies included which provided specific measurements, high intake for fruit was defined roughly as two or more portions per day, with low intake defined as less than two portions per day. The same two studies defined high vegetable intake as roughly two to three or more portions per day, with one defining low vegetable intake as less than three portions per day, and the other defining low vegetable intake as less than seven per week.

To get a broader picture across the studies, researchers compared high intake and low intake using the highest and lowest intakes recorded in each individual study. Ten studies ranked dietary exposure as a measurement of the frequency participants ate a type of food within a day or week. Two studies ranked dietary exposure by asking participants their preference of certain types of food.

The sample sizes of the individual studies included ranged from 135 women to more than 11,000.

Researchers also looked at pre-determined diets to see if following a specific outline had a difference in miscarriage risk. While pre-determined diets such as the Mediterranean diet and the Fertility diet had no link to a lowered or raised miscarriage risk, researchers did find that a diet containing foods rich with antioxidant sources and low in pro-inflammatory food seemed to be associated with reduced miscarriage risk.

The only diet that showed an association with an increased risk of miscarriage was a diet rich in processed food, which was found to be associated with a miscarriage risk twice as high as those with low processed food intake.

Researchers didn’t find a clear connection between miscarriage risk, or reduction of miscarriage risk, in relation to intake levels of meat, red meat, white meat, fat and oil, and sugar substitutes. More research is needed to establish whether these foods contribute to miscarriage risk at high or low levels, or could also lower risk for pregnant people depending on their intake levels within an individuals’ diet.

It’s important to note that this research measured associations, not causality.

“Advice on diet is one of the most-discussed subjects for us when talking with pregnant women and birthing people,” Juliette Ward, a midwife with Tommy’s National Centre for Miscarriage Research, stated in the release.

“We know that baby loss is very rarely the result of someone’s lifestyle choices, but many people want to know how to be as healthy as possible in pregnancy. Following a healthy diet, taking supplements like Vitamin D and folic acid, exercise and trying to lower stress are all things people can try to do, but there’s been a lack of clear evidence on the links between diet choices and miscarriage.”

The research was funded by the Tommy’s National Centre for Miscarriage Research, through the University of Birmingham.

Researchers stated that they believe this study shines some light on steps prospective parents can make when attempting to conceive and during the early months of pregnancy in order to reduce risks.

“We strongly encourage couples to consider the importance of making positive lifestyle choices when planning for a family, and to continue with these healthy choices throughout their pregnancy and beyond,” Chung said. “By knowing that positive lifestyle choices can make a significant difference in reducing the risk of miscarriage, couples can feel empowered to take charge of their health and the health of their baby.”