To evaluate endoplasmic reticulum stress in women with recurrent pregnancy loss and those who had healthy births in the same age group. The level of the unfolded protein X box binding protein 1 (XBP-1) is measured. It is aimed to show the effect of endoplasmic reticulum stress on recurrent pregnancy loss.

Inclusion Criteria:

• with three or more miscarriages before 20 th week of gestation
• had no chronic or acute inflammatory disease
• used no steroids, anti-inflammatory, or antioxidant medications

Exclusion Criteria:

• had inflammatory diseases
• had systemic disease
• Anatomical abnormalities, infectious, endocrine, or genetic etiologies

Loss of 3 or more pregnancy between the ages of 18 and 45 and women who have given at least 1 healthy birth in the same age group.