A delivery of one or more living babies is counted as one live birth. Because frozen cycles use embryos formed from a previous stimulated cycle, no stimulation or retrieval is involved. As a result, these cycles are usually less expensive and less invasive than cycles using fresh embryos. In addition, freezing some of the embryos from a retrieval procedure may increase a woman s overall chances of having a child from a single retrieval. Embryos donated by couples who previously had ART may also be available.
Many clinics provide services for donor egg and embryo cycles.
Live birth rates do not vary much by the recipient s age when donor eggs or embryos are used. In general, the more cycles that a clinic performs, the narrower the range of its confidence interval and the more likely the clinic would be to have the same success rate if it treated other similar groups of patients under similar clinical conditions. Even though one clinic's success rate may appear higher than another s based on the confidence intervals, confidence intervals are only one indication that the success rate may be better. Other factors must also be considered when comparing rates from two clinics. For example, some clinics see more than the average number of patients with difficult infertility problems, while others discourage patients with a low probability of success.