Abnormal expression of MMP-9 and imbalance of MMP-9/TIMP-1 is associated with prolonged uterine bleeding after a medical abortion with mifepristone and misoprostol.
OBJECTIVE
To investigate the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitory of metalloproteinase-1 (TIMP-1) in women who had undergone a medical abortion and explore their possible role in the mechanism of prolonged uterine bleeding after a mifepristone-misoprostol abortion.


METHODS
Cross-sectional study.


METHODS
Tertiary referral university hospital.


METHODS
Forty women were recruited following a medical abortion with mifepristone and misoprostol, 20 with duration of bleeding >14 days and 20 with duration of bleeding <or= 14 days.


METHODS
Endometrial specimens were stained with hematoxylin and eosin for histological examination. The expression of MMP-9 and TIMP-1 was evaluated by immunohistochemistry.


METHODS
Histology was analyzed by light microscope and expression of MMP-9 and TIMP-1 was semi-quantitatively evaluated.


RESULTS
Histological examination showed residual villi and trophoblasts with inflammatory cell infiltration in women with duration of bleeding >14 days after a medical abortion (bleeding group), whereas each sample of women with duration of bleeding <or= 14 days after a medical abortion (control group) showed normal endometrial changes. Immunohistochemistry and semi-quantitative scoring showed a significantly decreased expression level of MMP-9 in the bleeding group, compared with the control group. There was no significant difference of TIMP-1 expression between the bleeding group and the control group. The MMP-9/TIMP-1 ratio value was significantly lower in the bleeding group than in the control group.


CONCLUSIONS
This study documents that prolonged bleeding after a medical abortion with mifepristone and misoprostol is associated with retained products of conception with inflammatory cell infiltration, abnormal expression of MMP-9 and imbalance of MMP-9/TIMP-1.
Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Li
L
Li
Zanhua
Z
Zhou
Lili
L
Huang
D000019:Abortifacient Agents / Q000009:adverse effects*; D000028:Abortion, Induced / Q000009:adverse effects* / Q000379:methods; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D015735:Mifepristone / Q000009:adverse effects*; D016595:Misoprostol / Q000009:adverse effects*; D011247:Pregnancy; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis*; D014592:Uterine Hemorrhage / Q000209:etiology* / Q000378:metabolism
D000019:Abortifacient Agents; D019715:Tissue Inhibitor of Metalloproteinase-1; D016595:Misoprostol; D015735:Mifepristone; D020780:Matrix Metalloproteinase 9