Table 2.
Mechanism |
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Sperm transport 1. Occlusion or obstruction of the cervix 2. Alteration of the cervical architecture and canal 3. Decreased quality, composition and amount of cervical mucus 4. Impaired entry of sperm cells 5. Reduced sperm permeability and progression 6. Increased effect of immunological defenses 7. Altered uterine shape 8. Altered contractile activity 9. Deviation and/or obstruction of tubal ostia |
Embryo migration and implantation 1. Distortion of the uterine cavity 2 Impaired endometrial function, growth and receptivity 3. Alteration to the endometrial and myometrial blood supply 4. Decreased angiogenesis, vascularization and arterial fibrosis 5. Impaired uterine contractions 6. Altered maternal–fetal cross talk |
Placentation 1. Impaired endometrium function, growth and receptivity 2. Alteration to the endometrial and myometrial blood supply 3. Decreased angiogenesis, vascularization and arterial fibrosis 4. Abnormal decidualization 5. Altered placental implantation and attachment |