Cervical tissue changes in women with miscarriage: a morphological and biochemical investigation.

Objective: To evaluate morphological and inflammatory events in the uterine cervix in first trimester miscarriages.

Design: Experimental study.

Setting: Sahlgrenska University Hospital, Gothenburg, Sweden.

Population: Nulliparous women with first trimester symptomatic (n = 7) or silent (n = 11) miscarriage scheduled for surgical evacuation and nulliparous women scheduled for surgical termination of first trimester pregnancies (control group n = 11).

Methods: Before evacuation, biopsies were obtained from the cervix. The specimens were either fixed in glutaraldehyde for electron microscopy or snap-frozen in liquid nitrogen and stored at -70 degrees C until analyses of interleukin-8 (IL-8) and matrix metalloproteinases (MMPs).

Main Outcome Measures: Ultrastructure of cervical tissue, cervical tissue levels of IL-8, immunohistochemistry of MMP-1, MMP-8, MMP-9 and IL-8.

Results: The organization of the cervical collagen framework was deranged, the fibroblasts were reactive and the number of activated mast cells appeared to be increased in specimens from women with miscarriage compared with controls. IL-8 was significantly increased in women with miscarriage. Immunohistochemistry of MMP-1 and MMP-8 did not demonstrate any significant difference between the groups. MMP-9 was significantly lower in specimens from women with symptomatic miscarriage compared to women with silent miscarriage and women in the control group.

Conclusions: An inflammatory-like response takes place in the cervix both in women with symptomatic and silent miscarriage. The intensity of the inflammatory response seems to be similar in the two groups. Therefore, inadequate cervical remodeling does not seem to be the reason why some miscarriages remain silent.