Births of Triplets or More Declining, U.S. Officials Say
The recent trend of multiple births, in which mothers using fertility treatments often gave birth to three or more babies, has dropped for the first time in a decade, federal health officials reported Tuesday.
After more than doubling from 1990 to 1998, the triplet-plus birthrate declined 4%, from 194 live births per 100,000 in 1998 to 185 in 1999, according to the Centers for Disease Control and Prevention and its National Center for Health Statistics, which Tuesday released its latest statistics on births in the United States.
Researchers credit improvements in the technology of fertility treatments, since about two-thirds of all triplet-or-more births are the result of fertility-enhancing treatments. In the earliest days of in vitro fertilization, doctors transferred as many as seven embryos to a woman’s womb, hoping one or more would grow into a fetus. Now, amid medical concern for the complications often faced by these babies and improvements in techniques, doctors as a rule implant no more than three or four.
“It suggests that refinements in reproductive health technology may be starting to have an impact,” said Joyce Martin, the CDC’s multiple-birth expert. “With some of the new techniques, they are finding that they can have a high success rate [by implanting] fewer embryos.”
Martin said that Tuesday’s report is the first sign of improving technology and that researchers did not expect to see the drop as soon as they did--and won’t be able to confirm it as a trend “until we see at least another year’s worth of data.”
But researchers were pleased, noting the ethical and medical complications of encouraging multiple births.
“There’s been a lot of concern about some of the serious consequences associated with the enormous rise in higher-order multiple births over the past decade,” said CDC Director Jeffrey P. Koplan. “Most of these babies are born premature and of low birth weight, which puts them at high risk for a variety of health threats, including infant death and severe lifelong disabilities.”
Infant mortality rates are 10 times higher for triplets than for singles, according to Martin. Also, “the typical triplet weighs about half of what the typical [single] weighs and is born about six weeks earlier,” she said.
In recent years, professional organizations have strongly urged that fewer embryos be implanted as part of the in vitro fertilization process--a recommendation that has been embraced as the technology has gotten better, experts said.
“Over the last 10 years, there has been a growing consensus in the medical community about limiting the number of embryo transfers people do,” said Dr. George R. Huggins, chairman of the department of obstetrics and gynecology at Johns Hopkins Bayview Medical Center in Baltimore.
At the same time, “there have been great improvements,” he added. “Ten years ago, the success rate was less than 20%. Today, it’s over 30% in many places. When you know your success rate is going up, that encourages you not to transfer as many embryos.”
The report also said that, while triplet-plus births are down, twin births continued to rise, from 110,670 in 1998 to 114,307 in 1999. The rate of twin births was also up 3%, from 28.1 per 1,000 live births in 1998 to 28.9 in 1999. This rate has risen more than 25% since 1990, the CDC said.
In another aspect of the report, the CDC found that the birthrate for mothers ages 15 to 19 continued its decline, slipping 3%. The rate has fallen 20% since 1991 and is now at a record low, the CDC said.
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Multiple Births Dip
After a steady rise, the number of births of triplets, quadruplets, quintuplets and other higher-number multiple births dropped in 1999.
Source: Centers for Disease Control and Prevention
