Characterization of pro-inflammatory, regulatory, and anti-inflammatory interleukins in placentas affected by acute fetal distress across gestational ages: a pilot study

BACKGROUND: Pregnancy requires finely regulated immunological adaptation, in which interleukins play central roles in mediating maternal-fetal communication and maintaining immune equilibrium. Acute fetal distress (distress acuta) is associated with inflammatory processes that may compromise placental function and pregnancy outcomes. The present study aimed to investigate the expression patterns and distribution of selected interleukins-IL-1α, IL-2, IL-4, IL-6, IL-7, IL-8, and IL-10-in placental tissues across three gestational stages (28, 31, and 40 weeks). METHODS: A retrospective exploratory study was conducted on placental tissues obtained from 15 participants with acute fetal distress (n = 5 per group) and 5 control samples at 40 weeks of gestation. Immunohistochemical analysis with semi-quantitative assessment and nonparametric statistical methods was applied. RESULTS: Distressed placentas demonstrated increased expression of pro-inflammatory interleukins, particularly IL-1α, IL-2, and IL-8, compared to controls. IL-2 expression appeared to decrease toward term, while IL-7 and IL-8 showed relatively consistent activity across gestational stages. Anti-inflammatory interleukins IL-4 and IL-10 demonstrated reduced expression in distressed placentas, whereas control samples showed comparatively higher levels. In contrast, IL-6 expression remained relatively stable across gestational stages in both groups. Correlation analysis indicated coordinated interleukin expression patterns across placental compartments. CONCLUSIONS: These findings may suggest an altered interleukin profile in placental distress acuta, characterized by a shift toward a pro-inflammatory environment. However, given the exploratory design and limited sample size, the results should be interpreted with caution, and further studies are required to confirm these observations.