These may include severely low numbers of sperm, poor quality of sperm, or defects in the egg membrane which prevent sperm passage. Newer techniques of micromanipulation may correct these problems. If more than the appropriate number of embryos needed for transfer are obtained, they may be frozen and held until the end of reproductive capability. The transfer of multiple embryos could result in the growth of more than one fetus. Recently, there have been reports of IVF pregnancies involving four, five and six fetuses.
Embryo transfer is the procedure by which the embryo is placed into the uterus.
It may occur 2 to 7 days after fertilization. Some patients may be candidates for day 5 - 7 transfer of blastocysts . No anesthesia is necessary, and the procedure is not painful. It is important for the patient's bladder to be full because the transfer is done under ultrasound guidance. She can empty her bladder 10 minutes after the procedure.