Effects of vaginal seeding on gut microbiota, body mass index, and allergy risks in infants born through cesarean delivery: a randomized clinical trial.

BACKGROUND: Vaginal seeding-exposure of neonates to maternal vaginal fluids-has been proposed to improve the microbiota of infants born through cesarean delivery, but its impacts on the infants' subsequent health outcomes remain unclear. OBJECTIVE: This study aimed to examine the impacts of vaginal seeding on gut microbiota, growth, and allergy risks in infants born through cesarean delivery. STUDY DESIGN: This randomized controlled trial was conducted at Liuyang Maternal and Child Health Care Hospital in Hunan, China. We estimated that a minimum sample size of 106 was needed by assuming a standardized effect size of 0.6 for the primary outcomes, with a statistical power of 80%, a 2-sided type I error of 0.05, and an expected loss to follow-up rate of 15%. Finally, 120 singleton term pregnant women scheduled for cesarean delivery were enrolled from November 2018 to September 2019. Infant follow-up was completed in September 2021. The participants were randomized in a 1:1 ratio to the vaginal seeding group (n=60; infants were swabbed immediately after birth using gauze preincubated in maternal vagina) or the control group (n=60; routine standard care). The first set of primary outcomes was infant body mass index and body mass index z-scores at 6, 12, 18, and 24 months of age. The other primary outcome was the total allergy risk score at 18 months for 20 common allergens (each scored from 0-6 points). Characteristics of gut microbiota, overweight/obesity, and allergic diseases and symptoms were included as secondary outcomes. The main analyses were performed according to the modified intention-to-treat principle. RESULTS: Of 120 infants, 117 were included in the analyses. Infant body mass index and body mass index z-scores did not significantly differ between the 2 groups at any of the 4 time points, with the largest difference in point estimates occurring at 6 months: the mean (standard deviation) body mass index was 17.5 (1.4) kg/m2 and 17.8 (1.8) kg/m2 in the vaginal seeding and control groups, respectively (mean difference, -0.31 kg/m2 [95% confidence interval, -0.91 to 0.28]; P=.30), and body mass index z-score was 0.2 (1.0) and 0.4 (1.1), respectively (mean difference, -0.20 [95% confidence interval, -0.58 to 0.18]; P=.31). The median total allergy risk score was 1.5 (interquartile range, 0.0-4.0) in the vaginal seeding group and 2.0 (interquartile range, 1.0-3.0) in the control group (median difference, 0.00 [95% confidence interval, -1.00 to 1.00]; P=.48). For infants from the vaginal seeding group, the relative abundance of genera Lactobacillus and Bacteroides in the gut microbiota was slightly yet nonsignificantly elevated at birth and 6 months, and the risk of overweight/obesity was lower at 6 months (0/57 vs 6/59; relative risk, 0.03 [95% confidence interval, 0.00-0.57]; P=.03) though not at subsequent time points. Other secondary outcomes did not differ between groups. No adverse events related to the intervention were reported. CONCLUSION: For infants born through cesarean delivery, vaginal seeding has no significant impacts on the gut microbiota, growth, or allergy risks during the first 2 years of life.

Maternal exposure to the production of fireworks and reduced rate of new onset hypertension in pregnancy.

BACKGROUND: Carbon monoxide (CO) is one of the main substances contained in fireworks. Previous studies suggested that CO may have protective effect on the development of hypertension of pregnancy. METHOD: The authors conducted a prospective cohort study in Liuyang, Hunan, China between January 2010 and December 2011. Demographic and life-style variables of the participating pregnant women were obtained through structured interview with the women and clinical data were retrieved from antenatal medical records. Density of fireworks factories was defined as the number of fireworks factories per 1000 residents in the township where the mothers resided during pregnancy. Multiple logistic regression analysis was used to analyze the independent association between maternal exposure to the production of fireworks and new onset hypertension in pregnancy. RESULTS: A total of 5976 pregnant women were included in the final analysis. Density of fireworks factories was inversely correlated with incidence of new onset hypertension in pregnancy (Pearson correlation coefficient = -0.29, p < 0.001). Multiple logistic regression analysis showed that, compared with women who resided during pregnancy in a township with 0-0.25 fireworks factories per 1000 residents, the rates of new onset hypertension in pregnancy in women who resided in a township with 0.26-1.00 fireworks factories per 1000 residents (Odds Ratio = 0.66, 95% confidence interval: 0.46, 0.96) and >1.5 fireworks factories per 1000 residents (Odds Ratio = 0.65, 95% confidence interval: 0.44, 0.97) were reduced by more than 30%. CONCLUSION: Maternal exposure to the high density of fireworks factories is associated with reduced risk of developing new onset hypertension in pregnancy.

[Pre-conceptive factors on the birth ponderal index].

OBJECTIVE: To analyze the pre-conceptive factors on birth ponderal index (PI). METHODS: Fourteen towns were selected randomly from the 37 towns of Liuyang county, Hunan province, through cluster sampling in a prospective cohort study. Information was collected on all the women registered at the Maternity and Child Care Departments, and were planning to give birth in the coming year plus willing to receive a blood test and then followed-up until delivery. Single factor analysis would involve chi-square test and correlation analysis, while the multiple-factor analysis would adopt binary logistic regression method. RESULTS: A total of 1368 women were recruited in the cohort and 611 of them had a delivery of one child. Means of birth weight, birth length, and birth PI were (3.26 ± 0.43) kg, (50 ± 0.46) cm and 26.08 ± 3.43, respectively. Data from the multiple stepwise regression analysis showed that income (OR = 6.920, 95%CI: 1.089 - 43.974) and cortisone levels (OR = 5.121, 95%CI: 0.886 - 29.611) were related to low PI, while LDL-C (OR = 3.736, 95%CI: 0.848 - 16.461), waistline (OR = 6.846, 95%CI: 1.441 - 32.532), education (OR = 0.169, 95%CI: 0.029 - 0.995), and insulin (OR = 0.141, 95%CI: 0.016 - 1.277) were related to high PI. CONCLUSION: Birth PI was associated with income, waistline, education, insulin, cortisone, and LDL-C. Before conception, women should go through necessary tests and keep a good physical condition to reduce their neonates of having abnormal PI.

[Changes in blood pressure and related determinants before and during normal pregnancy].

OBJECTIVE: To study the longitudinal changes of blood pressure (BP) and its related determinants before and during normal pregnancy. METHODS: 14 townships were randomly selected by cluster random sampling method from 37 townships in Liuyang city, Hunan province. Subjects are all women at childbearing age in these 14 townships registered from April 2008 to December 2011. When the subjects visited to the local maternity and child-care agencies for pre-marital check, they were face-to-face interviewed and asked to fill out the questionnaire and finish the medical examination. Following-up program was carried out until delivery, with BP and other pregnancy information checked and collected. Analysis on variance of data regarding repeated measurements were used to investigate the changes of BP and related determinants. RESULTS: A total of 611 cases with complete data were recruited, after excluding 41 cases who were diagnosed as pregnancy-induced hypertension. Finally, data on 570 healthy women with singleton pregnancies was analyzed. Systolic blood pressure (SBP) at pre-pregnancy, first trimester, second trimester and third trimester were (109.9 ± 12.9) mm Hg, (100.6 ± 9.6) mm Hg, (102.6 ± 10.1) mm Hg, (107.8 ± 10.9) mm Hg, respectively while the diastolic blood pressure (DBP) of pre-pregnancy, first trimester, second trimester and third trimester were (71.1 ± 9.0) mm Hg, (64.3 ± 6.6) mm Hg, (65.1 ± 6.8) mm Hg, (68.3 ± 8.1) mm Hg, respectively. The pre-pregnancy BP was lower than the three periods after pregnancy. BP of the third trimester was higher than that of the ones at first or second trimesters, with the difference statistically significant. SBP and DBP both indicated that there were statistically significant changes in the four periods and the linear trend test showed statistically significant. Pre-pregnancy BMI, pre-pregnancy waist circumference and annual per capita income were determinants which affecting the changes of BP. Higher pre-pregnancy body mass index (BMI), wider pre-pregnancy waist circumference and higher annual per capita income were associated with higher BP, while annual per capita income mainly affecting the pre-pregnancy BP. CONCLUSION: BP of the three periods after pregnancy were lower than that of pre-pregnancy. BP of the third trimester was higher than both the first and second trimesters'. Pre-pregnancy BMI, pre-pregnancy waist circumference and annual per capita income were determinants which affecting the changes of BP.