Association of endothelial nitric oxide synthase and MTHFD1 polymorphismswith idiopathic recurrent pregnancy loss in Iranian women

Recurrent pregnancy loss (RPL) is one of the most common and important complications ofpregnancy that affects 1–5% of couples (Baek, Lee et al. 2007). RPL is defined by the AmericanSociety for Reproductive Medicine (ASRM) as two or more consecutive pregnancy losses before20 weeks of gestation (documented by ultrasound or histopathological examination)(PracticeCommittee of the American Society for Reproductive Medicine 2008).RPL is a multifactorial disorder and various factors including anatomic anomalies of the uterusor cervix, chromosomal abnormalities, hormonal and endocrinologic disorders, reproductive tractinfections, immunologic causes such as thrombophilia and lifestyle factors as well asenvironmental factors have been known to contribute in the etiology of RPL (Lanasa, Hogge etal.