Maternal Dietary Intakes and Risk of Spontaneous Abortion: A Systematic Review

Background: The loss of a fetus before the 20th week of pregnancy is known as spontaneous abortion (SA). Objective: This systematic review aimed to evaluate the results of previous studies about the dietary intake of mothers who suffered from SA. Methods: We conducted a comprehensive search in the Web of Science, Cochrane, PubMed, ProQuest, Google Scholar, Science Direct, and Scopus databases to collect relevant published studies between 1990 and November 2022. The data from case-control and cohort studies that had assessed dietary intakes before and during pregnancy of women with SA were included. Results: High consumption of butter increases the risk of SA, but a very low intake of olive oil and omega-3 fatty acids can reduce the risk of SA. In addition, an adequate intake of high-quality proteins and calcium from dairy products and enough intake of fiber and phytochemicals from chocolate, fresh fruits, and vegetables can reduce the risk of SA. A number of mechanisms, such as providing essential nutrients for fertilization and implantation, promoting fetal growth, reduction of inflammatory conditions, and insulin resistance, have been proposed to explain the protective effects of these food groups against SA. Conclusion: An unhealthy diet and eating sufficient amounts of these food groups will be helpful and recommended.