Lipiodol Prior to FET (LIFE)

Inclusion Criteria: * Women undergoing IVF/ICSI * Having indications for freeze-all (day-3 or day-5) * Agree to have ≤ 2 frozen embryos transferred * TSH \< 2.5 mIU/mL * Permanent resident in Viet Nam * Agree to participate in the study by signing the inform consent Exclusion Criteria: * Iodine allergy * History of salpingectomy or tubal ligation * History of using Lipiodol® within 6 months prior, starting from the screening time * At high risk of having Fallopian tube disorders (history of Chlamydia infection, history of pelvic inflammatory diseases, current endometriosis) * Having evidence of Fallopian tube disorders on Hysterosalpingo - Foam Sonography (HyFoSy), hysterosalpingography (HSG), ultrasonography or laparoscopy * Having untreated intrauterine lesions such as endometrial polyps, submucosal fibroids, etc which affect the outcome of IVF treatment * Have a history of thyroid disease or being treated for thyroid disease * Undergoing curettage within 30 days before performing HSG technique * Patients having embryos from oocyte donation or in vitro maturation (IVM) cycles * Unable or unwilling to attend Lipiodol® procedure * Participating in another interventional study at the same time