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 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.

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 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.

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.

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 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.