Recurrent pregnancy loss is defined as three or more consecutive miscarriages before 20 weeks. The main investigations recommended are testing for antiphospholipid antibodies, hysterosalpingography or sonohysterography to check for uterine anomalies, karyotyping of both parents and any fetal tissue to check for genetic abnormalities, and checking the thyroid, glucose, and thrombophilia profiles. The results of these tests can help identify causes like antiphospholipid syndrome, structural uterine issues, chromosomal translocations, thyroid abnormalities, or inherited bleeding disorders and guide further treatment.