WEDNESDAY, Jan. 4 (HealthDay News) -- The birth rate for twins in the United States has jumped by 76 percent since 1980, government health officials reported Wednesday.
Most of the increase appears linked to new fertility treatments that make it easier for older women to conceive, according to a report released by the U.S. Centers for Disease Control and Prevention.
"The growth in twin birth rate has occurred in all age groups, although the largest growth has been among older mothers," said study lead author Joyce A. Martin, an epidemiologist in the Division of Vital Statistics, Reproductive Statistics Branch at CDC's National Center for Health Statistics.
One reason for the increase is that mothers have been a little older, Martin said, "and women in their 30s are more likely to have a multiple birth."
However, only about one-third of the rise in twin births is attributable to the mother's age, Martin said.
"Most of the increase is likely the result of fertility-enhancing therapies, which is also more common among older mothers," she said.
Other highlights of the report:
While most twins are delivered safely and grow up fine, twin birth does carry added danger to both infant and mother, Martin noted. "The growth in twinning has added to the number of infants that are born at risk," she said.
"More than half of
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