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2002 Assisted Reproductive Technology (ART) Report: Section 5—ART
TRENDS, 1996–2002 |
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This
report marks the eighth 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 gives us 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 1996–2002.
Is the use of ART increasing?
Figure 40 shows the number of
ART cycles performed, the number of live-birth deliveries, and the number
of live infants born using ART from 1996 through 2002. The number of ART
cycles performed in the United States increased 78% overall, from 64,681
cycles in 1996 to 115,392 in 2002. The number of live-birth deliveries
increased 128%, from 14,507 in 1996 to 33,141 in 2002. The number of live
babies born who were conceived using ART also increased steadily between
1996 and 2002. In 2002, a total of 45,751 infants were born, an increase
of 120% over 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 live babies born is greater than the number of live-birth
deliveries.
Figure 40:
Number of ART Cycles Performed, Number of Live-Birth Deliveries, and
Number of Live Babies Born Using ART, 1996–2002.
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Are live birth rates improving?
Figure 41
presents live birth rates for the four primary types of ART cycles. Live
birth rates are presented per transfer rather than per cycle because that
is the only way to directly compare cycles using fresh embryos with those
using frozen embryos. Trends in live birth rates were considered in two
ways. First, we assessed whether there was a change in the live birth rate
over the previous year (that is, we compared the 2002 live birth rates
with the 2001 live birth rates). We also assessed the total change in live
birth rates from 1996 (the first full year of data collection) through
2002.
Between 2001 and 2002, the live birth rate for fresh–nondonor
cycles increased 4%, from slightly more than 33% in 2001 to about 35% in
2002. Likewise, during the same time period, live birth rates increased 6%
for frozen–nondonor cycles, 6% for fresh–donor cycles, and 8% for
frozen–donor cycles. The live birth rates from 1996 through 2002 increased
24% for fresh–nondonor cycles, 49% for frozen–nondonor cycles, 29% for
fresh–donor cycles, and 39% for frozen–donor cycles.
Figure 41:
Live Births per Transfer, by Type of ART Procedure, 1996, 2001, and 2002.
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Are singleton live birth rates improving?
Singleton 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 42 presents singleton
live birth rates for the four primary types of ART cycles. Singleton live
birth rates are presented per transfer rather than per cycle because that
is the only way to directly compare cycles using fresh embryos with those
using frozen embryos. Trends in singleton live birth rates were considered
in two ways. First, we assessed whether there was a change in the
singleton live birth rate over the previous year (that is, we compared the
2002 singleton live birth rates with the 2001 singleton live birth rates).
We also assessed the total change in singleton live birth rates from 1996
(the first full year of data collection) through 2002.
Between 2001 and 2002, the singleton live birth rate for fresh–nondonor
cycles increased 5%, from slightly more than 21% in 2001 to about 23% in
2002. Likewise, during the same time period, singleton live birth rates
increased 9% for frozen–nondonor cycles, 5% for fresh–donor cycles, and 7%
for frozen–donor cycles. The singleton live birth rates from 1996 through
2002 increased 31% for fresh–nondonor cycles, 53% for frozen–nondonor
cycles, 27% for fresh–donor cycles, and 37% for frozen–donor cycles.
Figure
42: Singleton Live Births per Transfer, by Type of ART Procedure,
1996, 2001, and 2002.
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Are live birth rates improving for all ART patients or only
for those in particular age groups?
Figure 43 presents live birth
rates per transfer, by woman’s age, for ART cycles using fresh nondonor
eggs or embryos. Trends in live birth rates were considered in two ways.
First, we assessed whether there was a change in the live birth rate over
the previous year (that is, we compared the 2002 live birth rates with the
2001 live birth rates). We also assessed the total change in live birth
rates from 1996 (the first full year of data collection) through 2002.
Between 2001 and 2002, the live birth rate increased 5% for women younger
than 35, from about 41% in 2001 to 43% in 2002. Likewise, during the same
time period, live birth rates increased 6% among women 35–37 and 4% for
women 38–40. For women 41 or older, live birth rates were similar between
2001 and 2002. The increase in live birth rates from 1996 through 2002 was
28% for women younger than 35, 28% for women 35–37, 22% for women 38–40,
28% for women 41–42, and 22% for women older than 42.
Figure
43: Live Births per Transfer for ART Cycles Using Fresh Nondonor Eggs
or Embryos, by Woman’s Age, 1996, 2001, and 2002.
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Are singleton live birth rates improving 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 44 presents singleton
live birth rates per transfer, by woman’s age, for ART cycles using fresh
nondonor eggs or embryos. Trends in singleton live birth rates were
considered in two ways. First, we assessed whether there was a change in
the singleton live birth rate over the previous year (that is, we compared
the 2002 singleton live birth rates with the 2001 singleton live birth
rates). We also assessed the total change in singleton live birth rates
from 1996 (the first full year of data collection) through 2002.
Between
2001 and 2002, the singleton live birth rate increased 6% for women
younger than 35, from about 25% in 2001 to slightly more than 26% in 2002.
Likewise, during the same time period, live birth rates increased 5% among
women 35–37, 4% for women 38–40, and 7% for women older than 42. There was
no change in the singleton live birth rate among women 41–42 years old.
From 1996 through 2002, the singleton live birth rate for women younger
than 35 increased 36%, from about 19% in 1996 to about 26% in 2002.
Likewise, over the same time period, live birth rates increased 31% for
women 35–37, 25% for women 38–40, 25% for women 41–42, and 35% for women
older than 42.
Figure
44: Singleton Live Births per Transfer for ART Cycles Using Fresh
Nondonor Eggs or Embryos, by Woman’s Age, 1996, 2001, and 2002.
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Have multiple birth rates
changed?
Multiple-infant births are associated with greater
problems for both mothers and infants, including higher rates of caesarean
section, prematurity, low birth weight, and infant disability or death.
Figure 45 shows multiple-infant
birth rates for the four primary types of ART cycles. Trends in
multiple-infant birth rates were considered in two ways. First, we
assessed whether there was a change in these rates over the previous year
(that is, we compared the 2002 rates with the 2001 rates). We also
assessed the total change in multiple-infant birth rates from 1996 (the
first full year of data collection) through 2002.
Figure
45:
Multiple-Infant Births per Live-Birth Delivery, by Type of ART Procedure,
1996, 2001, and 2002.
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Have twin and triplet-or-more birth rates changed?
Figure 46 compares twin and
triplet-or-more birth rates for ART cycles using fresh nondonor eggs or
embryos in 1996 (the first full year of data collection), 2001, and 2002.
Twins made up the vast majority of multiple-infant births in each of these
years. Since 1996, the triplet-or-more birth rate for fresh–nondonor
cycles has decreased, but there has been no change in the twin birth rate.
It is important to note that
twins, albeit to a lesser extent than triplets or more, are still at
substantially greater risk for illness and death than singletons. These
risks include low birth weight, preterm birth, and neurological
impairments such as cerebral palsy. Both the twin and triplet-or-more
birth rates remain significantly higher for ART births than for births
resulting from natural conception.
Figure
46: Twin Births per
Live-Birth Delivery and Triplet-or-More Births per Live-Birth Delivery,
for Fresh–Nondonor Cycles, 1996, 2001, and 2002.
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Previous ART Reports
Implementation of the Fertility
Clinic Success Rate and Certification Act of 1992
Assisted Reproductive Technology: Embryo
Laboratory
Date last reviewed:
03/27/2006
Content source: Division
of Reproductive Health,
National Center for Chronic Disease
Prevention and Health Promotion
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