Relationship Between Dietary Inflammatory Index During The Second Trimester Of Pregnancy And Adverse Pregnancy Outcomes

Objective To assess the diet quality of pregnant women during the second trimester by using the dietary inflammatory index (DII) and analyze the relationship between the DII of second trimester of pregnancy and the serum inflammatory markers. To clarify the validity of the DII in evaluating diet quality of pregnant women and explore the DII influence on pregnancy outcomes by cohort study, in order to provide evidence for dietary intervention during pregnancy.Methods A total of 253 women with singleton pregnancy for 16-20 weeks who had received regular prenatal care during August 2014 through April 2015 at a hospital in Hefei were enrolled in the prospective cohort study after signing informed consent forms. Maternal demographic data, previous pregnancy history and the history of disease were collected by a self-made questionnaire and physical examination. Pregnant women were asked to recall daily dietary intake of the 3 days prior to the survey. All dietary data were analyzed for energy intake and contents of various nutrients with the Nutritional analysis software, followed by calculation of DII according to previous reports. In addition, peripheral blood was collected and serum was separated and stored at -80℃. Particle enhanced turbidimetric immunoassay is used to detect the serum inflammatory marker high-sensitivity C- reactive protein (hs-CRP) levels. Participants were followed up until childbirth and pregnancy outcomes were collected, such as preterm birth, gestational diabetes mellitus, subclinical hypothyrodism, premature rupture of membranes, oligohydramnios, low birth weight and so on.Results DII scores of the 333 pregnant women during the second trimester of pregnancy ranged from -7.913 to 3.872. The median of DII was -3.498 (P25 and P75 were -5.029 and -1.805, respectively). Analyses were carried out using partial correlation analyses, adjusting for maternal age, pre-pregnancy BMI and so on. Partial correlation analyses showed significant positive correlation between the DII and the inflammatory markers hs-CRP(>3.3mg/mL) (r=0.196, P<0.001). By using quartile grouping according to DII scores, the participants were divided into three groups, namely the lower quartile group (anti-inflammatory diet group,<-5.029), P25-P75 group (intermediate group,-5.029～-1.805) and the upper quartile group (pro-inflammatory diet group,>-1.805). Participants in the highest tertile of DⅡ scores (i.e. with a more pro-inflammatory diet) had a higher risk for preterm birth, GDM and LBW. The differences among groups were statistically significant (P<0.05). The differences among other adverse pregnancy outcomes groups were not statistically significant (P>0.05). Multivariable logistic unconditioned regression showed that the risk factors for preterm birth were the DII of second trimester of pregnancy and work pressure (OR=1.355,95% CI:1.096-1.675 and OR=2.2% 0,95% CI:1.160～4.482). The risk factors for GDM and LBW were the DII of second trimester of pregnancy(OR=1.284,95% CI:1.104～1.495 and OR=1.582,95% CI:1.187-2.108).Conclusion Some conclusions can be summarized as follows:(1) DII can be used to assess diet quality of pregnant women during the second trimester; (2) The DII and the inflammatory markers hs-CRP levels were positively correlated; (3) Participants in the highest tertile of DII scores had a higher risk for preterm birth, GDM and LBW; (4) The DII can predict the risk of preterm birth, GDM and LBW. This study suggests that DII can be used to improve diet structure of pregnant women during the second trimester in order to reduce the risk of adverse pregnancy outcomes.