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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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 (aOR)=1.01, 95%CI: 0.74-1.37]. The associations with preterm birth were not statistically significant in further analysis by the type of nutritional supplements, time of initiation, and the frequency of supplementation. In addition, the association between the compliance score of taking supplements and the rate of preterm delivery was not statistically significant, either. CONCLUSION: 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.

[Relationship between micronutrients supplementation during periconceptional period and serum concentration of vitamin E in the 1st trimester of gestational period].

OBJECTIVE: To explore the association of maternal periconceptional folic acid or multiple micronutrients supplementation during periconceptional period and the serum vitamin E (Vit.E) concentration in the 1st trimester of gestational period. METHODS: A retrospective cohort study was conducted based on the prenatal health care system and clinical laboratory information system. Totally, 22 171 pregnant women who had their prenatal health care and gave birth in Tongzhou Maternal & Child Health Hospital of Beijing from Jan. 2016 to Dec. 2018 were recruited. The usage patterns of nutritional supplements [folic acid (FA) or multiple micronutrients (MM)] during periconceptional period were independent variables, and serum Vit.E concentration and serum Vit.E concentration≥11.2 mg/L in the 1st trimester of gestational period were outcome variables for generalized linear regression model and Logistic regression model, respectively, to analyze the relationships between the independent and outcome variables. RESULTS: The range of the serum Vit.E concentration in the 1st trimester of gestational period was 5.2-24.0 mg/L, and the median concentration was 10.1 (8.8-11.6) mg/L; the excess rate of the serum Vit.E of those who took MM supplementation was 0.3%, and the rates for the groups of FA only or no nutritional supplements used were both 0.1%. Compared with women without nutritional supplement or the women taking FA, the women who took MM had higher serum Vit.E levels in the 1st trimester of gestational period (both P < 0.05). The women taking FA or MM initiated before the conception showed that the serum Vit.E concentration in the 1st trimester of gestational period was higher than that after the conception (P < 0.05), and the serum Vit.E concentration of women who took regularly was higher than that of irregular taking (P < 0.05); with taking compliance elevated, the serum Vit.E concentration of the two groups of women taking FA or MM increased (P < 0.05). The risk of serum Vit.E concentration≥11.2 mg/L among the women taking MM was higher than that of the women without nutritional supplements or taking FA only [odds ratio (OR)=1.36, 95% confidence interval (95%CI): 1.21-1.53; OR=1.39, 95%CI: 1.31-1.48)]; women who took FA or MM showed a lower risk for serum Vit.E concentration≥11.2 mg/L of taking it after the conception than before, the ORs (95%CI) were 0.86 (95%CI: 0.77-0.96) and 0.88 (95%CI: 0.81-0.95), respectively; the women taking the two supplements regularly had higher risk for serum Vit.E concentration≥11.2 mg/L than irregular taking, the ORs (95%CI) were 1.16 (95%CI: 1.05-1.29) and 1.13 (95%CI: 1.04-1.22) for FA and MM users, respectively; with the compliance increasing, the women taking MM had a higher risk of serum Vit.E levels≥11.2 mg/L in the 1st trimester [OR (95%CI) was 1.10 (1.07-1.14)], but for FA users, the OR (95%CI) was 1.04(1.00-1.08). CONCLUSION: Vit.E nutritional status in women in early gestational period in Beijing was generally good, and the excess rate of serum Vit.E was higher in women who took MM during periconceptional period than those without nutritional supplement or taking FA only, suggesting that women need to consider their own Vit.E nutritional status to choose the type of nutritional supplements during periconceptional period, so as to avoid related health hazards.

[Maternal periconceptional folic acid supplementation and its effects on the prevalence of fetal neural tube defects].

OBJECTIVE: To find out the status of folic acid supplementation among women, to evaluate the prevention effects on neural tube defects (NTDs), and to explore the factors impact on folic acid supplementation compliance. METHODS: Based on the routine data of 92 121 women in prenatal health care and birth defect surveillance system in Tongzhou District of Beijing from 2013 to 2018, we described the prevalence of periconceptional folic acid supplementation, pre-pregnancy folic acid supplementation and regularly folic acid supplementation (compliance supplementation). Trend χ2 tests were used to evaluate the change of folic acid supplementation prevalence. The prevalence difference among the women with folic acid supplementation and without supplementation were tested with Fisher's exact test. Factors asso-ciated with folic acid supplementation compliance rate were analyzed with univariate and multivariate Logistic regression model. RESULTS: The prevalence of periconceptional folic acid supplementation during the six years was 90.08% and it was increased from 2013 to 2018, but the rate of pre-pregnancy and regular supplementation was only 41.5% and declined from 2013 to 2018, especially 2013 to 2015. The prevalence of NTDs among the fetuses whose mothers took folic acid during periconceptional period was 5.5/10 000, while the prevalence for the fetuses whose mothers did not take folic acid was 19.7/10 000 (P < 0.001), the rates ratio was 27.9% (χ2=23.74, P < 0.001). The difference between the prevalence of NTDs among the fetuses whose mothers took folic acid only and multiple micronutrients was not statistically significant. After controlling the confounding factors, it was found that the compliant folic acid supplementation rates in women, whose household registrations were outside Beijing and whose education levels were junior high school or below, and who were younger than 25 years old, and who were multiparas and who were pre-pregnancy underweight or obese, were lower than those of the corresponding control groups (P < 0.05). CONCLUSION: The rate of folic acid supplementation among women in Tongzhou District of Beijing was relatively high, but their compliance was poor. Women who did not take folic acid during periconception seriously affected the prevention effect of NTDs. We should focus on women who are younger than 25 years old, lower educated, pre-pregnancy underweight or obese, multiparas and nonlocal household registers, in order to improve the periconceptional folic acid supplementation compliance and improve the effects of NTDs prevention.

[Relationship between serum vitamin E concentration in first trimester and the risk of developing hypertension disorders complicating pregnancy].

OBJECTIVE: To investigate the incidence of hypertension disorders complicating pregnancy (HDCP) and vitamin E (VE) nutritional status among pregnant women in Beijing, and to determine the relationship between serum VE concentration in the first trimester of pregnancy and the risk of developing HDCP. METHODS: A retrospective cohort study was performed including 22 283 cases of pregnant women who underwent singleton deliveries in Tongzhou Maternal & Child Health Hospital of Beijing from January 2016 through December 2018 and received tests of serum VE concentrations in the first trimester of pregnancy. Nonconditional Logistic regression model was used to analyze the association between serum VE concentration levels and the risk of developing HDCP. RESULTS: The total incidence of HDCP was 5.4%, with the incidence of gestational hypertension around 2.1% and the incidence of preeclampsia-eclampsia around 3.3%. The median concentration of serum VE in early pregnancy was 10.1 (8.8-11.6) mg/L, and 99.7% of the participants had normal serum VE concentrations. The incidence of gestational hypertension and that of preeclampsia-eclampsia had been annually increasing in three years; a linear-by-linear association had also been observed between the serum VE concentrations and the years of delivery. According to the results of the univariable and the multivariable Logistic regression analyses, higher risks of developing HDCP had been observed among women with higher serum VE concentrations. Compared to those with serum VE concentrations in interquartile range (P25-P75) of all the participants, the women whose serum VE concentrations above P75 were at higher risks to be attacked by HDCP (OR = 1.34, P < 0.001), gestational hypertension (OR = 1.39, P = 0.002), or preeclampsia-eclampsia (OR = 1.34, P = 0.001), as suggested by the results of the multivariable Logistic regression model analyses. In addition, the women with serum VE concentrations of 11.2 mg/L or above had a significantly higher risk of developing HDCP than those whose serum VE concentrations of P40-P60 of all the participants, and this risk grew higher as serum VE concentrations in the first trimester of pregnancy increased. CONCLUSION: Women in Beijing are at good nutritional status. From January 2016 to December 2018, the incidence of HDCP increased with serum VE concentration level, and serum VE concentration of 11.2 mg/L is an indicator of an increased risk of developing HDCP, suggesting that pregnant women should take nutritional supplements containing VE carefully.