The twin birth rate rose 2 percent for 2004, to 32.2 twins per 1,000 total births, another record high. The twinning rate has climbed 42 percent since 1990 (from 22.6), and 70 percent since 1980 (18.9). The number of live births in twin deliveries rose to 132,219, nearly double the number reported for 1980 (from 68,339).
In contrast to the continued upswing in twin births, the rate of triplet and higher-order multiple births (triplet/+ birth rate) declined 6 percent for 2004, to 176.9 per 100,000, from 187.4 in 2003. The triplet/+ birth rate (the number of triplets, quadruplets, quintuplets, and other higher-order multiples per 100,000 live births) soared by more than 400 percent between 1980 and 1998 (from 37.0 to 193.5 per 100,000 births) (125). Since 1999, however, this rate has been comparatively stable, trending slightly downward; the current year level is 9 percent lower than the 1998 peak. In 2004, 7,275 triplets/+ were born, a drop of 5 percent from the previous year, and the lowest number reported since 1997. Similar trends in twinning and in triplet/+ birth rates have been observed over the last several decades in England and Wales.
One of our most frequently asked questions is about multiple births. For your convenience multiple births since 1971 are available here.