Preliminary Study On The Correlation Between Fetal Growth Restriction And Bacterial Overgrowth In Small Intestine

Background and ObjectiveFetal growth restriction（FGR）means that fetal growth does not reach its due genetic potential due to the influence of various pathological factors.The incidence of FGR is about 6-19.3%at home and abroad.The occurrence of FGR significantly increases perinatal adverse pregnancy outcomes and neonatal mortality.During pregnancy,the maternal intestinal microecology should be maintained in a dynamic equilibrium state,and the destruction of this balance may lead to the occurrence of Small intestinal bacterial overgrowth（SIBO）.SIBO affects the uterine environment and fetal intrauterine development,and is closely related to a variety of pregnancy complications.SIBO is a nutritional malabsorption syndrome caused by colonic bacteria transfer to the small intestine,small intestinal stasis,and bacterial over reproduction,and is associated with irritable bowel syndrome,Crohn’s disease,Parkinson’s disease,hypothyroidism,diabetes and other diseases,but there is still a lack of research in FGR.The Methane Hydrogen Breath Test（MHBT）diagnoses SIBO by detecting changes in the concentration of hydrogen（H₂）and methane（CH₄）in the exhaled air.The positive predictive value of MHBT breath test is 80%,the sensitivity is 85.7%,and the specificity is 90.9%,which is a relatively reliable method for the diagnosis of SIBO.The purpose of this study was to detect SIBO by MHBT,to explore the relationship between FGR and SIBO,and to preliminarily explore the role of SIBO,serum inflammatory indicators,hemoglobin and lipid metabolism in the occurrence and development of FGR,so as to provide a basis for the clinical diagnosis and treatment of FGR.MethodWe randomly selected pregnant women who received perinatal care in the Third Affiliated Hospital of Zhengzhou University from June 2019 to December 2020.According to the inclusion and exclusion criteria,70 FGR pregnant women who met the criteria were selected as the case group（Group A）.Seventy healthy pregnant women with normal fetal development who were enrolled in the Third Affiliated Hospital of Zhengzhou University during the same period were randomly selected as the control group（Group B）.SIBO was detected by MHBT,and the patients were divided into two groups according to the results of MHBT:SIBO positive group（Group C）and SIBO negative group（Group D）.The percentages of white blood cells,neutrophils,hemoglobin,hypersensitive C-reactive protein and lipid metabolism were detected in all pregnant women.The differences of serum indexes were compared among groups,and the correlation between FGR and maternal SIBO was analyzed.Results（1）MHBT breath test results of Group A and Group B showed that 48 out of 70pregnant women in Group A were SIBO positive,the positive rate of SIBO was 69%,compared with 12 out of 70 pregnant women in Group B,the positive rate of SIBO was17%（12/70）,the difference was statistically significant（P<0.05）.（2）The comparison of hydrogen expiratory concentration at each time point between Group A and Group B showed that there were statistically significant differences in hydrogen concentration at 60min,80min and 100min of expiratory（P<0.05）,while there were no significant differences in basic hydrogen expiratory concentration,20min and 40min hydrogen concentration（P>0.05）.（3）Comparison of methane concentration levels at each time point between Group A and Group B showed that there was no statistical difference in the baseline concentration of methane gas,20min,40min,60min,80min and 100min hydrogen expiratory concentration between Group A and Group B（P>0.05）.（4）Group A and Group B in inflammatory biomarkers,hemoglobin and serum lipid metabolism,the results shown in Group A serum neutrophil,hypersensitive c-reactive protein percentage,total cholesterol,low density lipoprotein,apolipoprotein B,and free fatty acid is higher than Group B,and hemoglobin is lower than Group B,with statistical difference（P<0.05）;There was no significant difference in the number of white blood cells,triglyceride,high-density lipoprotein and apolipoprotein A1 between the two groups（P>0.05）.（5）According to the testing results of MHBT cases pregnant women can be divided into Group A1 and Group A2,compared two groups of pregnant women serum inflammatory biomarkers,hemoglobin and blood lipid metabolism,the results shown in Group A1 serum neutrophil,hypersensitive c-reactive protein percentage,total cholesterol,low density lipoprotein,apolipoprotein and free fatty acids were higher than that of Group A2,and hemoglobin is lower than Group A2,with statistical difference（P<0.05）;There were no significant differences in the number of white blood cells,triglyceride,high density lipoprotein and apolipoprotein A1between Group A1 and Group A2（P>0.05）.Conclusions1、The incidence of SIBO in FGR pregnant women was significantly higher than that in healthy pregnant women of the same gestational age.2、When pregnant women with FGR develop SIBO,it may induce or aggravate inflammatory response,lead to anemia,and cause abnormal lipid metabolism in the body.