The Effects of Body Mass Index on Second-Trimester Amniotic Fluid Cytokine and Matrix Metalloproteinase Levels.

AIM: The aim of this study was to determine the effects of obesity on amniotic fluid (AF) inflammatory markers in second-trimester AF, testing the hypothesis that there is a relationship between maternal body mass index (BMI) and fetal inflammatory exposure.

METHODS: AF was obtained from 84 singleton pregnant women undergoing elective amniocentesis for karyotype analysis at 16-24 weeks of gestation between April 2014 and May 2016. The cell-free AF was used to analyze interleukin (IL)-1β and IL-6, and matrix metalloproteinase (MMP)-1, MMP-6, and MMP-13.

RESULTS: IL-1β levels were significantly higher in class II-III obese patients than in class I obese, overweight, and normal weight patients (14.68 ± 1.37 vs. 13.34 ± 1.86 vs. 13.00 ± 2.22 vs. 10.78 ± 1.92, respectively; p < 0.05). IL-6 levels were lowest in the normal weight group and highest in class II-III obese patients. MMP-1, MMP-6, and MMP-13 levels were also significantly higher in class II-III obese patients than in the other groups.

CONCLUSION: This study demonstrated that the fetuses of class II-III obese women are exposed in utero to higher cytokine and MMP levels than fetuses of lean women. Modification of current cutoff levels of intra-amniotic cytokines and MMPs according to the BMI could improve the accuracy of the prenatal diagnosis of intra-amniotic infection and inflammation.