Histologic chorioamnionitis: different histologic features at different gestational ages

Abstract

Objective: The aim of this study was to investigate the rate of the different histological chorioamnionitis (HCA) grade in relation to the gestational age in term and preterm delivery.

Methods: Three hundred and ninety-two women with singleton pregnancy with spontaneous onset of labor either prematurely or at term, with histologic diagnosis of HCA, were enrolled. Placentas were classified as: deciduitis and/or histologic chorioamnionitis within the membranes (HCA1); amnionitis or inflammation of the chorionic plate without funisitis (HCA2); and histologic chorioamnionitis with funisitis (HCA3). Microbiological culture was performed on both placental and fetal membrane samples.

Results: HCA1 was more frequent in women delivering at term than in preterm (p < 0.001). HCA2 was more represented in women delivering between 32 and 36 weeks (p < 0.001) and HCA3 occurred more frequently in those delivering within 32 weeks (p < 0.001). The positive bacterial culture was higher (p = 0.008) in presence of HCA3 in comparison with HCA1 and HCA2.

Conclusions: This study showed a significantly different distribution of HCA grades in relation to gestational age at delivery. HCA may represent the expression of different subtending etiologies and may also reflect specific immune competence of gestational tissues at different gestational ages, strengthening as pregnancy advances.

• Amnionitis
• funisitis
• intrauterine inflammation
• labor
• prematurity

Acknowledgements

The authors thank the Midwives team and all the Residents of the Obstetric Unit of Siena (Italy) for contributing to the collection of data for this study.