[Association between periconceptional supplementation of folic acid or multiple-micronutrients containing folic acid and preterm delivery in women].

To explore the association between periconceptional supplementation of folic acid or multiple-micronutrients containing folic acid(MMFA) and risk of preterm delivery in women with natural conception, singleton pregnancy and vaginal delivery. A retrospective cohort study was performed based on the prenatal health care system and hospital information system of Tongzhou Maternal and Child Health Hospital of Beijing and the women who had their prenatal care in the hospital from January 2015 to December 2018 were included. The information of 16 332 women who conceived naturally, had a singleton pregnancy, and delivered vaginally was collected. Compliance scores were constructed based on the time of initiation and the frequency of taking nutritional supplements. The association between maternal periconceptional micronutrient supplementation, including pure folic acid (FA) pills or MMFA and the rate of preterm delivery was evaluated using Logistic regression models. The preterm delivery rate (gestational week < 37 weeks) of the study population was 3.8%, and the mean (standard deviation) of gestational age was (38.98±1.37) weeks. A total of 6 174 (37.8%) women took FA during the periconceptional period, 8 646 (52.9%) women took MMFA, and 1 512 (9.3%) women did not take any nutritional supplements. The association between periconceptional supplementation of FA or MMFA and risk of preterm delivery in women was not statistically significant [adjusted odds ratio (a This study did not find an association between the risk of preterm delivery and the use of FA or MMFA during the periconcep-tional period in women with natural conception, singleton pregnancy, and vaginal delivery. In the future, multicenter studies with large-scale prospective cohort or population-based randomized controlled trials are warranted to confirm the association between taking FA or MMFA during the periconceptional period and preterm delivery among women.