Figure 49 shows the numbers of ART cycles performed, live-birth deliveries, and infants born using ART from 1996 through 2006. The number of ART cycles performed in the United States has more than doubled, from 64,681 cycles in 1996 to 138,198 in 2006. The number of live-birth deliveries in 2006 (41,343) was more than two and a half times higher than in 1996 (14,507). The number of infants born who were conceived using ART also increased steadily between 1996 and 2006. In 2006, 54,656 infants were born, which was more than two and a half times the 20,840 born in 1996. Because in some cases more than one infant is born during a live-birth delivery (e.g., twins), the total number of infants born is greater than the number of live-birth deliveries.

Intracytoplasmic sperm injection (ICSI) was originally developed to use in ART cycles to improve fertilization rates when severe male factor infertility was the indication for using ART. Today, this procedure is widely used even among couples without a diagnosis of male factor infertility.

Figure 50 shows the numbers of ART cycles performed using fresh nondonor eggs or embryos with or without ICSI and the numbers of cycles using frozen nondonor eggs or embryos from 1996 through 2006. During the past 11 years, while the number of fresh–nondonor cycles performed without ICSI remained stable, the number of fresh–nondonor cycles performed with ICSI increased four times from 14,885 in 1996 to 61,835 in 2006. The number of frozen–nondonor cycles more than doubled, from 9,445 in 1996 to 22,023 in 2006.

Note that the information on use of ICSI was not collected for ART cycles using frozen embryos; therefore, cycles using frozen embryos are presented together as one group.

Figure 51 shows the numbers of ART cycles performed using fresh donor eggs or embryos with or without ICSI and cycles using frozen donor eggs or embryos. While the number of fresh–donor cycles performed without ICSI remained fairly stable during the past 11 years, the number of fresh–donor cycles performed with ICSI increased from 857 in 1996 to 7,039 in 2006. The number of frozen–donor cycles increased from 1,118 in 1996 to 5,992 in 2006. In particular, during reporting year 2006, fresh donor eggs with ICSI were used the most among all donor cycles.

Note that the information on use of ICSI was not collected for ART cycles using frozen embryos; therefore, cycles using frozen embryos are presented together as one group.

Figure 52 presents percentages of transfers that resulted in live births for ART cycles using fresh nondonor eggs or embryos with or without ICSI and for cycles using frozen nondonor eggs or embryos. Percentages of transfers that resulted in live births are presented rather than percentages of cycles that resulted in live births because this is the only way to directly compare cycles using fresh embryos with those using frozen embryos.

Overall, higher success rates were consistently observed among fresh–nondonor cycles than frozen–nondonor cycles. The percentage of transfers that resulted in live births for fresh–nondonor cycles performed without ICSI increased from 28% in 1996 to 37% in 2006. Over the same period, the percentage of transfers that resulted in live births for cycles using fresh nondonor embryos performed with ICSI remained slightly lower than without ICSI, but steadily increased. The percentage of transfers that resulted in live births for cycles using frozen nondonor embryos increased from 17% in 1996 to 29% in 2006, but was generally lower than the percentage of transfers that resulted in live births for cycles using fresh nondonor embryos.

Note that the information on use of ICSI was not collected for ART cycles using frozen embryos; therefore, such cycles are presented together as one group.

Figure 52: Percentages of Transfers That Resulted in Live Births Using Fresh or Frozen Nondonor Eggs or Embryos, by ICSI, 1996–2006.

Figure 53 presents the percentages of transfers that resulted in live births for ART cycles using fresh donor eggs or embryos with or without ICSI and for cycles using frozen donor eggs or embryos. Percentages of transfers that resulted in live births are presented rather than percentages of cycles that resulted in live births because that is the only way to directly compare cycles using fresh embryos with those using frozen embryos.

Similar to the trends shown in Figure 52 for nondonor cycles, the success rates for cycles using fresh donor eggs or embryos were generally higher than for cycles using frozen donor eggs or embryos during 1996–2006. The percentage of transfers that resulted in live births for cycles that used fresh donor eggs or embryos performed without ICSI increased from 39% in 1996 to 56% in 2006. Over the same period, the percentage of transfers resulting in live births increased from 39% to 53% for cycles that used fresh donor eggs or embryos and were performed with ICSI, and from 21% to 32% for cycles that used frozen donor eggs or embryos.

Note that the information on use of ICSI was not collected for ART cycles using frozen embryos; therefore, such cycles are presented together as one group.

Singleton live births are an important measure of success because they entail a much lower risk than multiple-infant births for adverse infant health outcomes, including prematurity, low birth weight, disability, and death. Figure 54 presents percentages of transfers that resulted in singleton live births for ART cycles performed using fresh nondonor eggs or embryos with or without ICSI or for cycles using frozen nondonor eggs or embryos.

While the total numbers of nondonor cycles using ICSI greatly increased over the past 11 years (see Figure 50), the percentage of transfers that resulted in singleton live births from these cycles were not any higher than those without ICSI: 17% to 24% with ICSI versus 17% to 25% without ICSI.

Over the same period, the percentage of transfers that resulted in singleton live births among frozen–nondonor cycles increased from 12% to 22%.

Note that the information on use of ICSI was not collected for ART cycles using frozen embryos; therefore, such cycles are presented together as one group.

Singleton live births are an important measure of success because they entail a much lower risk than multiple-infant births for adverse infant health outcomes, including prematurity, low birth weight, disability, and death. Figure 55 presents percentages of transfers that resulted in singleton live births for ART cycles performed using fresh donor eggs or embryos with or without ICSI or for cycles using frozen donor eggs or embryos.

The percentage of transfers that resulted in singleton live births were consistently higher for fresh–donor cycles than for frozen–donor cycles. Percentages increased for fresh–donor cycles without ICSI from 22% in 1996 to 33% in 2006; a similar increase from 24% to 33% was observed for cycles with ICSI. Over the same period, the percentage of transfers that resulted in singleton live births increased from 15% to 24% for frozen–donor cycles.

Note that the information on use of ICSI was not collected for ART cycles using frozen embryos; therefore,such cycles are presented together as one group.

Figure 56 presents percentages of transfers that resulted in live births, by woman’s age, for ART cycles using fresh nondonor eggs or embryos.

From 1996 through 2006, the percentage of transfers that resulted in live births for women younger than 35 increased 33%, from 34% in 1996 to 45% in 2006. Over the same period, the percentage of transfers that resulted in live births increased 28% for women 35–37, 24% for women 38–40, 31% for women 41–42, and 22% for women older than 42.

Singleton live births are an important measure of success because they have a much lower risk than multiple-infant births for adverse infant health outcomes, including prematurity, low birth weight, disability, and death. Figure 57 presents percentages of transfers that resulted in singleton live births, by woman’s age, for ART cycles using fresh nondonor eggs or embryos.

From 1996 through 2006, the percentage of transfers that resulted in singleton live births for women younger than 35 increased about 52%, from 19% in 1996 to 29% in 2006. Over the same period, the percentage of transfers that resulted in singleton live births increased 42% for women 35–37, 34% for women 38–40, 34% for women 41–42, and 30% for women older than 42.

Figure 57: Percentages of Transfers (Using Fresh Nondonor Eggs or Embryos) That Resulted in Singleton Live Births, by Woman’s Age, 1996–2006.

Figure 58 presents the trends for number of embryos transferred in fresh–nondonor cycles that progressed to the embryo transfer stage. From 1996 through 2006, cycles that involved the transfer of one embryo increased slightly, from 6% to 11%; cycles that involved the transfer of two embryos increased dramatically, from 10% in 1996 to 46% in 2006. Cycles that involved the transfer of three embryos increased from 23% in 1996 to 28% in 2006, and cycles that involved the transfer of four or more embryos decreased from 62% in 1996 to 16% in 2006.

Has the number of embryos transferred in each ART cycle changed for women younger than 35 who have more embryos available than they choose to transfer?

As shown in Figure 58, the number of embryos transferred in fresh–nondonor cycles has decreased during the past 11 years. Figure 59 shows the change over time in the number of embryos transferred for ART procedures in which the woman was younger than 35 and the couple chose to set aside some embryos for future cycles rather than transfer all available embryos at one time. Previous research suggests that the number of embryos available for an ART cycle is important in predicting success. Younger women also tend to have higher success rates (see Figure 14).

Overall, the number of embryos transferred decreased among couples who chose to transfer fewer embryos than were available. In 1996, almost two-thirds (64%) of ART cycles involved the transfer of four or more embryos; 33%, three embryos; 3%, two embryos; and less than 1%, one embryo. By 1998, the percentage of cycles in which four or more embryos were transferred had decreased to 33%; half of all ART cycles involved the transfer of three embryos; 16% of cycles, two embryos; and less than 1%, one embryo. By 2006, four or more embryos were transferred in only 3% of cycles, three in 16% of cycles, two in 75% of cycles, and one in 7% of cycles.