Multiple births occur when one woman gives birth to 3 or more babies at once. Twin births are sometimes also counted in the multiple birth statistics. Multiple births tend to be associated with a high incidence of prematurity, caesarian deliveries, low birth weight and generally greater health risks. Handicaps and language development problems are more common in triplets. Children from multiple births beyond triplets usually show some physical or cognitive disability. More specialized hospital care tends to be required than for singletons, meaning that they are sometimes split up and distributed to separate facilities.
Bringing up the children requires resources not available to many families. Multiple births to an older woman can be a daunting prospect, as she may already have children and was not expecting to have two or three more.
Fertility improvement techniques and pregnancies late in life increase the chance of multiple births. Fertility techniques such as in vitro imsemination were previously unknown; fertility drugs enhance ovulation; and older women release more eggs up until menopause.
Fertility treatment has led to a large increase in multiple births. In the UK the number of triplets has doubled in the decade to 1990. The number of women in the USA giving birth to 3 or more babies at once quadrupled between 1980 and 2000. The number of multiple live births per 100,000 live births increased by 252% for whites and 52% for blacks. The rate of twins rose 30% in the same period. The overall rate has been rising by 11% each year. In 1994, there were 4594 such births, most of them to white married college-educated women beyond 30 years of age.