A maximum of two good quality embryos are to be replaced. Patients are asked to keep a mildly full bladder so that the uterus can be visualized by abdominal sonogram during the procedure. A bivalve speculum is inserted into the vagina and the cervix is cleaned with warm saline and culture medium. The axis, degree of flexion and the configuration of the uterine cavity are determined by transabdominal ultrasound examination before the transfer. Under transabdominal ultrasound guidance, the outer catheter is inserted into the cervical canal 4 cm from the external os, with the tip just beyond the internal os. A malleable obturator is used if difficulty is encountered. The inner transfer catheter with the loaded embryo(s) is then inserted into the uterine cavity via the outer cannula. The aim is to put the tip of the inner catheter inside the uterine cavity 6 cm from the external os and care was taken not to advance the tip beyond 1 cm from the uterine fundus. The transfer volume is gently expelled by the technician. The catheters will be held in place for 30 seconds. Both the inner and outer catheters will be checked by the technician under the microscope to make sure that the embryos have been replaced.