Recurrent Pregnancy Loss (RPL) is generally defined as the spontaneous loss of two or more pregnancy excluding confirmed molar or ectopic pregnancies. A pregnancy confirmed only by a urine or blood hCG test or biochemical tests counts, an ultrasound or tissue confirmation isn’t required, since access to early pregnancy ultrasound varies widely.
Genetic evaluation becomes relevant because chromosomal and genetic factors are among the most common identifiable causes, particularly after the second loss.

The testing is used to be recommended after two or more consecutive miscarriages, however newer guidelines recommends to not waits till third loss and start the work up from second pregnancy onwards.