This report marks the twelfth consecutive year that CDC has
published an annual report detailing the success rates for ART
clinics in the United States. Having several years of data provides
us with the opportunity to examine trends in ART use and success
rates over time. Because the first year of data collection, 1995,
did not include non-SART member clinics, we limit our examination of
trends to the years 1996–2006.
Is the use of ART increasing?
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.
Figure 49: Numbers of ART Cycles
Performed, Live-Birth Deliveries, and Infants Born Using ART,
1996–2006.
Have there been changes in the
type of ART cycles performed among women who used fresh or frozen
nondonor eggs or embryos?
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 50: Numbers
of ART Cycles Using Fresh or Frozen Nondonor Eggs or Embryos, by ICSI,
1996–2006.
Have there been changes in the types of ART cycles
performed among women who used fresh or frozen donor eggs or embryos?
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 51: Numbers of ART
Cycles Using Fresh or Frozen Donor Eggs or Embryos, by ICSI,
1996–2006.
Have there been improvements in the percentage of
transfers that result in live births among women who used fresh or
frozen nondonor eggs or embryos?
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.
Have there been improvements in the percentage of
transfers that result in live births among women who used fresh or
frozen donor eggs or embryos?
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.
Figure 53:
Percentages of Transfers That Resulted in Live Births Using Fresh or
Frozen Donor Eggs or Embryos, by ICSI, 1996–2006.
Have there been improvements in
the percentage of transfers that result in singleton live births
among women who used fresh or frozen nondonor eggs or embryos?
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.
Figure 54:
Percentages of Transfers That Resulted in Singleton Live Births
Among Women Using Fresh or Frozen Nondonor Eggs or Embryos, by ICSI,
1996–2006.
Have there been improvements in the percentage of
transfers that result in singleton live births among women who used
fresh or frozen donor eggs or embryos?
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 55: Percentages of Transfers
That Resulted in Singleton Live Births Among Women Using Fresh or Frozen
Donor Eggs or Embryos, by ICSI, 1996–2006.
Have there been improvements in
the percentage of transfers that result in live births for all ART
patients or only for those in particular age groups?
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.
Figure 56:
Percentages of Transfers That Resulted in Live Births for ART Cycles
Using Fresh Nondonor Eggs or Embryos, by Woman’s Age, 1996–2006.
Have there been improvements in
the percentage of transfers that result in singleton live births for
all ART patients or only for those in particular age groups?
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.
Has the number of embryos transferred in
fresh–nondonor cycles changed?
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.
Figure 58:
Percentages of Fresh–Nondonor Cycles That Involved the Transfer of
One, Two, Three, or Four or More Embryos, 1996–2006.
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.
Figure 59:
Percentages of Fresh–Nondonor Cycles That Involved the Transfer of
One, Two, Three, or Four or More Embryos in Women Who Were Younger
Than 35 and Set Aside Extra Embryos for Future Use, 1996–2006.
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