This review of recurrent pregnancy loss examines our current understan
ding of the major etiologies of this unfortunate condition including g
enetic and endocrine abnormalities, anatomic variations, autoimmune co
nditions, alloimmune problems, systemic disease, and infection. Diagno
stic protocols and treatment strategies are briefly presented. With a
high rate of spontaneous normal pregnancy outcome, great care must be
taken to do more good than harm.