Until the 1990s, Russia and the Soviet Union did not count, either as a live birth or as an infant death, extremely premature infants that were born alive but failed to survive for at least seven days (infants born weighing less than 1,000 g, of less than 28 weeks gestational age, or less than 35 cm in length, who that breathed, had a heartbeat, or exhibited voluntary muscle movement). Although such extremely premature infants typically accounted for only about 0.5% of all live-born children, their exclusion led to an estimated 22%–25% lower reported IMR. In some cases, too, hospitals or regional health departments were held accountable for lowering the IMR in their catchment area, infant deaths that occurred in the 12th month were "transferred" statistically to the 13th month (i.e., the second year of life), and thus no longer classified as an infant death.
Until the 1990s, Russia and the Soviet Union did not count, either as a live birth or as an infant death, extremely premature infants that were born alive but failed to survive for at least seven days (infants born weighing less than 1,000 g, of less than 28 weeks gestational age, or less than 35 cm in length, who that breathed, had a heartbeat, or exhibited voluntary muscle movement). Although such extremely premature infants typically accounted for only about 0.5% of all live-born children, their exclusion led to an estimated 22%–25% lower reported IMR. In some cases, too, hospitals or regional health departments were held accountable for lowering the IMR in their catchment area, infant deaths that occurred in the 12th month were "transferred" statistically to the 13th month (i.e., the second year of life), and thus no longer classified as an infant death.