Recurrent spontaneous abortion (RSA), also known as recurrent miscarriage, is a disorder related to pregnancy defined as two or more pregnancy losses during the first trimester. It affects about 2%-5% of couples trying to conceive. Chinese researchers have investigated the potential involvement of Cbl proto-oncogene like 1 (CBLL1) in RSA, since CBLL1 has been reported to vary with the menstrual cycle in the endometrium.