Purpose: Intrauterine Growth Restriction (IUGR) is the inability of the fetus to achieve the biologically accessible growth potential. Irisin is a recently discovered adipomyokine with a crucial role in energy metabolism. Our current study aimed to investigate the relationship between the isolated IUGR in the third trimester and maternal serum irisin level.
Materials and methods: This prospective case-control study included total 137 pregnant women who were between the 24th and 39th gestational weeks and who applied to the University of Health Sciences, Ankara Zekai Tahir Burak Women's Health Training and Research Center, between 2016 October-2017 May. The Study Group consisted of 68 pregnant women who were diagnosed with Isolated IUGR with Estimated Fetal Weight (EFW) <10th percentile. The Control Group consisted of 69 low-risk uncomplicated pregnant women, matched with the Study Group in terms of gestational week, and with EFW between 10th and 90th percentiles. Demographic data, clinical findings, fetal Doppler parameters, and obstetric-neonatal outcomes were evaluated. Maternal serum irisin levels were measured by ELISA (Enzyme-Linked Immunosorbent Assay) Method and compared between the groups.
Results: Maternal serum irisin level was found to be significantly lower in IUGR Group as compared to the Control (3.83 ng/ml vs. 4.78 ng/ml, p < .001, respectively). There was a positive correlation between maternal serum irisin level and duration of pregnancy, the weight gain during pregnancy, birth weight, fetal abdominal circumference measurement and cerebroplacental ratio (r = 0.18, p = .03; r = 0.17, p = .04; r = 0.37, p < .001; r = 0.35, p < .001; r = 0.27, p = .001, respectively). Binary Logistic Regression Analysis showed that maternal serum irisin level is an independent estimator of IUGR [OR %95 CI: 8.33 (3.22 - 25.01)]. AUC (Area Under the Curve) analysis of maternal irisin for IUGR estimation was 0.75 (p < .001, 95% CI = 0.67 - 0.82). The optimal cutoff value was below 3.86 ng/ml for maternal irisin level with a sensitivity of 54.41% and a specificity of 88.41%, positive predictive value of 82.22% and negative predictive value of 66.30%.
Conclusion: Low level of maternal serum irisin in pregnancies with isolated IUGR was consistent with the role of irisin in metabolic pathways and with the increased risk of metabolic diseases in the future life of IUGR fetuses and their mothers.
Keywords: Irisin; abdominal circumference; cerebroplacental ratio; intrauterine growth restriction; last trimester.