A maximum of two embryos will be transferred to the uterus for possible implantation. Even by limiting the embryos transfered, we still encounter twin pregnancies in approximately 25% of our patients. Any excess good embryos will be frozen and can be used for a future ivf cycle. They can also be kept for up to 5 yrs. Some of our patients have had a single ivf egg collection and subsequently had three children as a result. The first baby came from the fresh embryos and then after the birth, the frozen embryos resulted in two further pregnancies and deliveries.